ATT GSM Course

Unit 1

Background and Fundamentals

Version 1.0.0August 2, 1993 -- 18:18:13 [unit01]

AT&T Proprietary − Use pursuant to Company Instructions

Overview of the GSM Cellular System


OVERVIEW OF AGS1200The Pan-European GSM Cellular System



1-2 Overview of the GSM Cellular System


OVERVIEW OF AGS1200The Pan-European GSM Cellular System

MSCPSTN

MSC-BSS Trunks

Inter-office Trunks

BSC2 BSC

3

BSC1


Volume 1

AGS1200

Version 1.0.0August 24, 1995 -- 18:06:38 [rjt1037.eps]


Overview of the GSM Cellular System 1-3


AGS1200 VERSUS CC1200





AGS1200 VERSUS CC1200

Background and Basic Cellular Concepts

GSM System Services and Station Features

System Architecture Overview

Mobility Management and Location Updating

Call Management

The GSM Radio Link

AT&T’s GSM Product Line- IBS 2000 BSS- 5ESS MSC- AT&T’s OMC

Condensed

Japan Digital Cellular - IDOGSM Data Services

Version 1.0.0March 4, 1993 -- 15:03:06 [rjt1036.eps]




WHAT IS GSM?

GSM is a Global System for Mobile communications. Hopefully when you hear or see the phrase"global system for mobile communication," you visualize a wireless telephone.

While GSM is a Pan-European cellular mobile radio system, it is much more. GSM is a "publictelecommunications system." This point should become clear as various GSM requirements arepresented in the upcoming units in this course. A GSM mobile user will be able to receive servicessimilar to those provided in the fixed public switched telephone network. Whereas there are manymobile radio systems that are not connected to the public telephone networks, those that are mustconform to public telecommunication system standards and possess recognizable features.

For example, it must be possible to make and receive telephone calls in the same general way as infixed networks. Users must be able to dial a phone number and be connected to the number ofinterest, irregardless whether the dialed number corresponds to a mobile or fixed station. By usingthe same national and international dialing procedures that exist today, a mobile user should be ableto dial anyone’s phone number in the world. Similarly, incoming calls from anywhere in the worldmust be possible. Data and messaging services must also be available.

In short, a GSM cellular phone must behave just like a fixed telephone, but without wires.

Version 1.0.0April 15, 1992 -- 17:55:13 [djw1041.txt]




WHAT IS GSM?

Group Speciale Mobile

Global System for Mobile communication

Version 1.0.0July 7, 1992 -- 19:09:38 [djw1143.eps]




AGS1200 AND THE GSM SPECIFICATION

The following table can be used as a quick guide to the GSM Specification documents. The totalnumber of pages in the GSM recommendations exceed 5000.

_ _____________________________________________________GSM Series Topics Covered_ ______________________________________________________ _____________________________________________________1.02 - 1.06 GSM overview, glossary

abbreviations, service phases_ _____________________________________________________2.01 - 2.88 GSM services and features_ _____________________________________________________3.01 - 3.88 PLMN functions, architecture,

numbering and addressing, procedures_ _____________________________________________________4.01 - 4.88 MS-BSS interface_ _____________________________________________________5.01 - 5.10 Radio link_ _____________________________________________________6.01 - 6.32 Speech processing_ _____________________________________________________7.01 - 7.03 Terminal adaptation_ _____________________________________________________8.01 - 8.60 BSS-MSC interface, BSC-BTS interface_ _____________________________________________________9.01 - 9.11 Network interworking, MAP_ _____________________________________________________11.01 - 11.11 MS conformity and SIMs_ _____________________________________________________11.20 - 11.40 BSS, MSC, HLR, VLR, simulation and testing_ _____________________________________________________12.00 - 12.21 Network management_ _____________________________________________________

A more detailed index to all sections within the GSM specifications is provided in Appendix 1,with the information organized as follows:

— Section number— Number of pages in the section— Latest version number— Date of latest version— Section/Recommendation title

There are three ways to obtain copies of GSM recommendation sections:

• Borrow and copy section(s) from a co-worker.

• Borrow and copy section(s) from a designated contact for your work location (see Appendix 2for the names of the contacts).

• Request a paper copy of a section via Linus (see Appendix 2 for procedures).





AGS1200 AND THE GSM SPECIFICATION

GSM = Global System for Mobile communication

COMPLEMENTSBUT

DOES NOT REPLACE!

GSM

1.02

1.06

GSM

2.02

2.88

GSM

3.01

3.88

GSM

4.01

4.88

GSM

8.01

8.60

GSM

9.01

9.11

GSM

11.01

11.20

GSM

11.21

11.40

GSM

12.00

12.21

GSM

5.01

5.10

6.01

6.32

7.01

7.03

Version 1.0.0January 31, 1992 -- 17:41:02 [djw1030.eps]







Background





EVOLUTION OF WIRELESSACCESS TECHNOLOGY





EVOLUTION OF WIRELESSACCESS TECHNOLOGY

Now

1991

199?

Cellular RadioTechnology

PagingTechnology

Cordless TelephoneTechnology

AnalogSingle Channel

DigitalMulti Channel

AnalogTechnology

DigitalTechnology

PersonalCommunications

Networks

ContinuousMiniaturization

ContinuousMiniaturization

Version 1.0.0March 12, 1992 -- 22:04:45 [djw1027.eps]




WIRELESS SERVICESTECHNOLOGY PERSPECTIVE




Background and F

undamentals

WIR

EL

ES

S S

ER

VIC

ES

TE

CH

NO

LO

GY

PE

RS

PE

CT

IVE

National

Regional

LocalArea

SelectedSites

Home/Office

Mobility

HighSpeed

VehicularSpeeds

Walking(LimitedArea)

Walking(Very Limited

Radius)

Coverage

Full2-Way

2-WayBroadcast

Utility

2-WayInitiate Only

1-WayReceive Only

Paging Airphone

CellularSpecializedMobile Radio

DigitalMicrocell

(PCN)

CT-2/Telepoint

Cordless

Version 1.0.0

May 2, 1992 -- 16:51:14

[djw1062.eps]

AT

&T

Proprietary−

Use pursuant to C

ompany Instructions

Overview

of the GSM

Cellular System

1-15


MARKET TRENDS IN WIRELESS COMMUNICATION





MARKET TRENDS IN WIRELESS COMMUNICATION

PAGERS

CORDLESS TELEPHONES

CELLULAR TELEPHONES

11%

25%

40%

1988 1989 1993

1988 1989 1993

1988 1989 1993

Growth

Growth

Growth

Mill

ions

ofUn

its0

20

40

60

Mill

ions

ofUn

its

0

20

40

60

Mill

ions

ofUn

its

0

20

40

60





CELLULAR SYSTEMS IN EUROPETODAY

The chart shows the types of cellular system(s) in service in each country and the radio band ofoperation (in MHz). Also provided are the year that cellular service was put into operation.

Version 1.0.0February 9, 1992 -- 16:27:55 [djw0683.txt]




CELLULAR SYSTEMS IN EUROPETODAY

Country Type of System (RF band∗) In Service_ ________________ _ ____________________________ _ ________

Austria C-Netz (450), D-Netz (900) 1984

Belgium AFT2 (450) 1987

Cyprus NMT-900 (900) 1988

Denmark NMT-450 (450), NMT-900 (900) 1982

Finland NMT-450, NMT-900 1982

France Radiocom-2000 (200, 400, 800)NMT-450, NMT-900 1985

Western Germany C-Netz (450) 1986

Iceland NMT-450 1986

Ireland TACS-900 (900) 1985

Italy RTMS (450), TACS-900 1985

Luxembourg AFT2 (450) 1985

Netherlands AFT2 (450) 1985

Norway NMT-450, NMT-900 1981

Portugal C-Netz (450) 1989

Spain TMA (450), TACS-900 1982

Sweden NMT-450, NMT-900 1981

Switzerland Natel-C (900) 1987

Turkey NMT-450 1986

United Kingdom TACS-900 1985

∗ RF band in MHz

Version 1.0.0January 31, 1992 -- 17:52:20 [djw0683.pic]




OBJECTIVES OF THE PAN-EUROPEANGSM BASED SYSTEM

The primary objective of the Global System for Mobile communication (GSM) organization was toproduce an integrated mobile communication standard that supports international roaming.Increased capacity was a secondary objective.





OBJECTIVES OF THE PAN-EUROPEANGSM BASED SYSTEM

• Integrated European system withinternational roaming

• Increase available cellular radio capacity

• Take advantage of digital price/performance

• Accommodate new technology and services





ADOPTION OF GSM STANDARD





ADOPTION OF GSM STANDARD

AustriaBulgariaBelgiumCzechoslovakiaDenmarkFederal Republic of GermanyFinlandFranceGreeceHungaryIrelandItalyLuxembourgNetherlandsNorwayPolandPortugalRomaniaSpainSwedenSwitzerlandUnited Kingdom

AustraliaIndiaSingapore<and more??>

Version 1.0.0June 30, 1992 -- 13:41:02 [djw0685.pic]




KEY EVENTS

The pan-European cellular mobile radio system was conceived in 1982 by a committee of theConference of European Posts and Telecommunications Administrations (CEPT). CEPT foresaw agrowing need during the 1980s and 1990s for public cellular radio, but accompanied by a wideningdivergence of systems, unless a standard was available to positively encourage convergence.

The GSM objective was to create the possibility of opening public service throughout Europe in theearly 1990s. At the outset it was recognized that the best way of achieving this was to create a newEuropean-wide cellular standard. The intended outcome was, however, visualized only in generalterms and the full extent of the standard did not become apparent until a fairly advanced stage in itsdevelopment.

The way to 1991 was paved by a number of bold technical decisions, sometimes ahead of thenecessary confirmatory research and development work, or based on trials carried out under thesupervision of a GSM working party.

One of the technically far-reaching decisions, made in 1987, rested on the results of radio andspeech coding trials held in Paris which pointed strongly towards the adoption of Time DivisionMultiple Access (TDMA) digital techniques. In 1987 the GSM system became a digital system.

The GSM is part of CEPT and is based in Brussels, Belgium. The acronym GSM is commonlyused to refer to both the group as well as the Pan-European cellular network project. The firstcommercial system is expected to be activated the end of August 1991 in the Federal Republic ofGermany.

CEPT Conference European Postal TelecommunicationsWARC Radio World ConferenceEEC European Economic CommunityGSM Global System for Mobile communication





KEY EVENTS

1982 CEPT adopts WARC 79recommendation allocating890-915 MHz and935-960 MHz for land mobile

GSM created to set standard

1985 EEC supports GSM standardsthroughout community

1987 Digital technology standardsset for TDMA, speech coding,channel coding, andmodulation method

13 European countries agreeto install systems in 1991

1988 Industrial development started

1991 First systems deployed





EXPECTED GROWTH IN EUROPEANCELLULAR 1991-1994

Most of the cellular growth in Europe is expected to be on the GSM system. However, there willstill be some growth on the analog cellular systems for some years to come, especially wherecapacity is not an issue. By 1994, more than 4 million subscribers are expected to be on the GSMsystem compared to a total of over 11 million cellular subscribers in Europe. This figure does notinclude subscribers to the new Personal Communications Networks (PCNs) operating at 1800MHz.

There are estimates that more than 15 million GSM mobile subscribers may exist by the end of thedecade.1

1 . "Uncommon Market", Electronic Engineering Times, December 23/30.

Version 1.0.0March 1, 1992 -- 21:52:59 [djw0900.txt]




EXPECTED GROWTH IN EUROPEANCELLULAR 1991-1994

10

12

8

6

4

2

1991 1992 1993 1994

Subscribers

(Millions)

Souce: EMCI Inc. Year

Total

Analog Cellular

GSM

Version 1.0.0June 30, 1992 -- 15:21:41 [djw1135.eps]




SECOND GENERATION CELLULAR STANDARDS

Looking at today’s cellular products, we find at least six different incompatible standards employedin different parts of the world. All these "first generation" systems rely on analog frequencymodulation for speech transmission and in-band signaling to move control information betweenterminals and the rest of the network during a call.

Second generation cellular will conform to at least three different standards: one for westernEurope--Global System for Mobile communications, one for North America--an ElectronicIndustry Association Interim Standard (IS-54), and a third for Japan.

While the European and Japanese standards will be applied to completely new cellular systemsoperating in dedicated frequency bands, the North American standard specifies dual-modeoperation. It incorporates the first generation standard, Advanced Mobile Phone System (AMPS),and adds a digital voice transmission capability to new subscriber equipment. Thus, IS-54 is anenhancement to, rather than a replacement for, present cellular technology. The situation in NorthAmerica is enriched, not to mention complicated, by at least three other dual-mode AMPSenhancements in various stages of development. Thus, in cellular, North America and Europeseem to be moving in opposite directions. Europe will migrate from a collection of incompatibleanalog systems to a single digital system, while North America, which has enjoyed from the outsetcontinental compatibility of all cellular equipment, will see the deployment of various dual-modetechnologies, all sharing a common analog standard, but with radically different advancedtechnologies.





SECOND GENERATION CELLULAR STANDARDS

• GSM (European Digital Standard)new 900-MHz Spectrum, TDMA, 270 kb/s

• IS-54 (N. American Digital Standard)existing 900-MHz Bands, TDMA, 48k kb/s

• JDC (Japanese Digital Cellular Standard)parts of IS-54 and GSM

Version 1.0.0March 15, 1992 -- 21:24:25 [djw0554.pic]




THE RADIO SPECTRUM





THE RADIO SPECTRUM

in Japan

830-832AirplanePhone

860-885Cellular

NTT & IDO(receive)

915-940Cellular

NTT & IDO(transmit)

1500-???PCN

frequencyin MHZ

in the U.S.

46 & 49CordlessPhones(CT-1)

824-849 & 869-894Cellular Phones

902-928ISM band

940-941"Telepoint"

(CT-2)

1850-1990PCN

frequencyin MHZ

in Europe

864-868CT-2

890-915 & 935-960Cellular Phones

(GSM)

1710-1880PCN

1880-1900DECT

frequencyin MHZ








Cellular SystemMajor Components





POTS / MOBILE TELEPHONE CONNECTIONS

The upper figure depicts a typical connection used for Plain Old Telephone Service (POTS) in thePublic Switched Telephone Network (PSTN). In these connections, a subscriber’s phone isconnected by lines to switching offices (sometimes called end offices) in the PSTN. These endoffices are connected to each other by a network of inter-switch trunks which may include otherswitches (not shown).

In the basic mobile connection, an end office is replaced with a Mobile-services Switching Center(MSC) which is connected by trunks and data links to a radio Base Station (BS) which covers thearea where the Mobile Station (MS) is located. The communications medium between the mobilestation and the base station is over a duplex radio frequency channel as shown.

Version 1.0.0June 30, 1992 -- 13:43:37 [djw0901.txt]




POTS / MOBILE TELEPHONE CONNECTIONS

SUBSCRIBERSET

SUBSCRIBERSET

. . .... . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . .. . . . . . . . . .. . . . . . . .. . . . . . .. . . . . . .. . . . . .. . . . . .. . . . .. . . . . .. . . .. . . . .. . . . .. . . .. . . .. . . .. . . .. . . .. . .. . . .. . . .. . .. . .. . . .. . .. . .. . .. . .. . .. . .. . .. . .. . . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . . .. . .. . .

. . . .. . .. . . .. . . .. . . .. . .. . . . .. . . .. . . .. . . .. . . . .. . . . .. . . . .. . . . .. . . . . .. . . . . .. . . . . .. . . . . . .. . . . . . .. . . . . . . .. . . . . . . . . .. . . . . . . . . . . .. . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . .. . . . . . . . . . . .. . . . . . . . .. . . . . . . . .. . . . . . .. . . . . . .. . . . . .. . . . . .. . . . . .. . . . .. . . . .. . . . .. . . . .. . . .. . . . .. . . .. . . .. . . .. . . .. . .. . . .. . . .. . .. . . .. . .. . .. . . .. . .. . .. . .. . .. . . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. .. . .. . .. . .. . .. .. . .. . .. . .. . .. .. . .. . .. .. . .. . .. . .. .. . .. .. . .. . .. .. . .. . .. .. . .. .. . .. . .. .. . .. .. . .. .. . .. . .. . .. .. . .. . .. . .. . .. . .. . . .. . .. . . .. . .. . . .. . . .. . .. . . . .. . . .. . . .. . . . .. . . . .. . . . . .. . . . . .. . . . . .. . . . . . . .. . . . . . . .. . . . . . . . . . . .. . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . .. . . . . . . . .... .. ...... . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . .. . . . .. . . . .. . .. . . .. . .. . .. . .. .. . .. .. . .. .. .. .. .. .. .. ... .. .. ... ... .. ... .. ... ... .. ... .. ... .. ... ... .. ... .. ... .. ... ... .. ... .. ... ... .. ... .. ... .. ... ... .. ... .. ... .. ... ... .. .. ... .. .. .

. .. .. .. .. . .. .. .. . .. .. . .. . .. . .. . .. . . .. . .. . . .. . . . .. . . . . .. . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . .. . . . .. . . .. . . .. . . .. . .. . . .. .. . .. . .. .. . .. .. .. .. . .. .. ... .. .. .. ... .. ... .. ... ... ... ... ... ... ... ... ... ... ... .... ... .... ... .... .... .... .... .... .... ..... ..... ... .... ... ... .. ... .. .. .. .. .. .. . .. .. . .. . .. . .. . . .. . . .. . . . . .. . . . . . . . . . . . . . . . . . . . . . . . .. . . ......SWITCHING

OFFICESWITCHING

OFFICE

LINE TRUNKS LINE

BASIC POTS CONNECTION

. ...... . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . .. . . . . . . .. . . . . . .. . . . .. . . . .. . . . .. . . .. . . .. . . .. . .. . . .. . .. . .. . .. . .. . .. .. . .. . .. .. . .. .. .. . .. .. .. .. . .. .. .. . .. .. .. .. . .. .. .. .. . .. .. .. .. . .. .. .. . .. .. .. .. . .. .. .. .. . .. .. .. .. . .. .. .. . .. .. .. .. . .. .. .. .. . .. .. .. .. . .. .. .. . .. .. .. .. . .. .. .. .. . .. .. .. . .. .. .. . .. .

. . .. . .. .. . .. . .. . .. . .. . .. . . .. . .. . . .. . .. . . .. . . .. . . . .. . . .. . . . .. . . . . .. . . . . .. . . . . . .. . . . . . . . .. . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . .. . . . . . . . .. . . . . . .. . . . . .. . . . . .. . . . .. . . . .. . . .. . . . .. . .. . . .. . . .. . .. . . .. . .. . .. . .. . .. . .. . .. .. . .. . .. .. . .. .. . .. .. .. . .. .. .. . .. .. . .. .. .. .. . .. .. .. . .. .. .. .. .. . .. .. .. .. .. .. . .. .. .. .. .. .. .. .. .. . .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ... .. .. .. .. .. .. .. .. .. .. .. .. . .. .. .. . .. .. . .. .. . .. . .. . .. . .. . .. . .. . . .. . . .. . . .. . . . .. . . . .. . . . . .. . . . . . .. . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . ......

MOBILESWITCHING

CENTERBASE

STATION

TRUNKS&

DATALINKS

SWITCHINGOFFICE

TRUNKS

SUBSCRIBERSET

BASIC MOBILE TELEPHONE CONNECTION

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . .. . . . . . . . . . . . .. . . . . . . . . . . .. . . . . . . . . . .. . . . . . . . .. . . . . . . . .. . . . . . . . .. . . . . . .. . . . . . . .. . . . . . .. . . . . . .. . . . . .. . . . . . .. . . . . .. . . . .. . . . . .. . . . . .. . . . .. . . . .. . . . .. . . . .. . . . . .. . . . .. . . . .. . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . . . .. . . . . .. . . . . . .. . . . . . . .. . . . . . . .. . . . . . . .. . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . . . .. . . . . . . . . . . . . .. . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . .. . . . . . . . . . . . . .. . . . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . .. . . . . . . .. . . . . . . .. . . . . . . .. . . . . . .. . . . . . .. . . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . .. . . . . .. . . . .. . . . .. . . . . .. . . . .. . . . .. . . . .. . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . . . .. . . . . . .. . . . . . .. . . . . . .. . . . . . . .. . . . . . . . .. . . . . . . . .. . . . . . . . .. . . . . . . . . . .. . . . . . . . . . . .. . . . . . . . . . . . . .. . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . .. . . . . . . . . . . .. . . . . . . . . . .. . . . . . . . . .. . . . . . . . .. . . . . . . . .. . . . . . . .. . . . . . . .. . . . . . .. . . . . . .. . . . . . .. . . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . .. . . . . .. . . . .. . . . .. . . . . .. . . . .. . . . . .. . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . . . .. . . . . . .. . . . . . .. . . . . . .. . . . . . . .. . . . . . . .. . . . . . . . .. . . . . . . . .. . . . . . . . . .. . . . . . . . . . .. . . . . . . . . . . . .. . . . . . . . . . . . . .. . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . .. . . . . . . . . . . . .. . . . . . . . . . .. . . . . . . . . .. . . . . . . . .. . . . . . . . .. . . . . . . .. . . . . . . .. . . . . . . .. . . . . . .. . . . . . .. . . . . .. . . . . . .. . . . . .. . . . . .. . . . . .. . . . .. . . . . .. . . . .. . . . . .. . . . .. . . . .. . . . . .. . . . .. . . . . .. . . . . .. . . . . .. . . . . . .. . . . . .. . . . . . .. . . . . . .. . . . . . . .. . . . . . .. . . . . . . . .. . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . . .. . . . . . . . . . . .. . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

MOBILESTATION

•

Version 1.0.0May 15, 1991 -- 11:09:45 [djw0901.ped]




LAYOUT OF A CELLULAR SYSTEM

The three major components of a cellular system are the Mobile-services Switching Center (MSC), the BaseStation (BS), and the Mobile Station (MS). In a typical cellular system, an MSC will serve a number of basestations, each of which serves a coverage area called a cell. The MSC interconnects the cellular network withthe land network. As a mobile travels from cell to cell, the MSC will switch the call from one base station toanother in what is called a "handover" or "handoff."

Each base station is assigned a set of radios and radio channels. Typically, one base station can serve severalmobile stations located within its cell area simultaneously.

TYPICAL MSC FUNCTIONS• Provide switched connections with PSTN• Provide switched connections between mobile subscribers• Provide coordination over signaling with mobiles• Coordinate the location and handover process• Provide custom services to mobile users• Collect billing data• Collect traffic data• Provisioning/service orders• Maintenance

TYPICAL BASE STATION FUNCTIONS• Provide RF transmission and reception• Provide data communications with the MSC and mobile stations• Locate mobiles• Perform routine maintenance testing• Perform equipment control and reconfiguration functions• Perform voice-processing functions• Perform call setup, call supervision, and call termination functions• Handover or receive a mobile from another cell-site while calls are in progress

TYPICAL MOBILE STATION FUNCTIONS• Provide a telecommunications interface to subscribers• Provide RF transmission and reception• Transmit and receive user information and control data• Perform voice-processing functions• Perform initialization and self-test functions





LAYOUT OF A CELLULAR SYSTEM

TO TELEPHONE NETWORK

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . .. . . .

...

...

......

...

MSC

...

...

MS

BS

BS BS

BS

BS

BS

BS

BSMSMSC

Base StationMobile StationMobile Switching Center

Land linksRadio link





MULTIPLE ACCESS METHODS

The two major access methods used for mobile telephone communications is Frequency DivisionMultiple Access (FDMA) or Time Division Multiple Access (TDMA). In FDMA, a given spectralallocation is broken into a number of individual radio channels, N, each of which can carry a singleinformation channel. In TDMA, the given spectral allocation is shared in time by a number ofusers, M, by assigning each to a specified time interval called a time slot.





MULTIPLE ACCESS METHODS

Frequency 1

Frequency 2

Frequency N

ch

ch

ch

TimeSlot 1

TimeSlot 2

TimeSlot M

ch ch ch

FREQUENCY DIVISION MUTIPLE ACCESS(FDMA)

TIME DIVISION MUTIPLE ACCESS(TDMA)

Version 1.0.0February 5, 1992 -- 17:16:47 [djw1038.eps]




FDMA/TDMA STRUCTUREUSED IN GSM

In the GSM cellular system there are 124 duplex radio channels (labeled 1 through 124), eachcontaining 8 time slots (labeled 0 through 7).





FDMA/TDMA STRUCTUREUSED IN GSM

FrequencyDomain

Frequency 1

Frequency 2

.

.

.

Frequency 124

ch

ch

ch

.

.

.

ch

Slot 0 Slot 1 Slot 7

ch

ch

ch

ch

. . . . . . . . . . . . . . . . .. . .. .. ... ... ..............................................................................................................................................................................................................................

. . . . . . . . . .. . . . . . . .. . .. . .. .. ... ... ..... ............................................................................................................................................................................................................................................ ..

..........

.

........

... .. .. ... .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. . .. .. .. .. . .. .. .. . .. .. . .. .. . .. . .. .. . .. . .. . .. . .. . .. . .. . .. . .. . . .. . .. . . .. . .. . . .. . . .. . . .. . . . .. . . .. . . . .. . . . . .. . . . . .. . . . . .. . . . . . .. . . . . . . . .. . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . .. . . . . . . .. . . . . .. . . . .. . . . .. . . . .. . . .. . . .. . . .. . . .. . .. . .. . .. . . .. .. . .. . .. . .. .. . .. .. . .. .. . .. .. .. .. . .. .. .. .. .

. .. .. .. .. .. ... .. .. .. ... .. ... .. ... .. ... ... ... .. ............

.

........

...... .... .... .... ... ... ... .. ... .. .. ... .. .. .. .. . .. .. .. . .. .. . .. . .. . .. . . .. . .. . . . .. . . . .. . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . .. . . . .. . . . .. . .. . . .. . .. . . . .. . . . .. . . . . .. . . . . . . . . .. . . . . . . . . . . . . . . . . . .. . . . . . . . . .. . . . . .. . . . .. . . .. . . .. . . .. . .. . .. . .. .. . .. .. . .. .. .. .. .. .. .. .. .. ... .. ... .. ... ... ... ... .... .... ..... ...... ........ ...

...................

Time Domain

.

ch.

.

.

.

.

.





SPECTRAL ALLOCATION

When a mobile station is assigned to an information channel in GSM, a radio channel and a timeslot are also assigned. Radio channels come in frequency pairs, one for the uplink path and one forthe downlink path.





SPECTRAL ALLOCATION

124Uplink

Channels

124DownlinkChannels

downlink

uplink

.. . . . . . .. . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . .. . . . . . . . . . . . . . .. . . . . . . . . . . . . .. . . . . . . . . . . . .. . . . . . . . . . . . .. . . . . . . . . . . .. . . . . . . . . . . .. . . . . . . . . . . . .. . . . . . . . . . . .. . . . . . . . . . . . .. . . . . . . . . . . . .. . . . . . . . . . . . . .. . . . . . . . . . . . . . .. . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . .. . . . . .

• GSM supports 124 duplex radio channels

• Each radio channel pair can support up to 8simultaneous calls





TDMA OPERATION

The complete set of allocated time slots is called a TDMA frame. Each mobile can transmit onlyduring its assigned time slot in a frame as shown. Thus, with TDMA, transmission from a givenmobile station to a base station occurs in bursts. In the base station to mobile station direction,which is supported on a different radio frequency channel, transmission is continuous. However,information directed to a given mobile station is sent only during the given mobile station’sassigned time slot for that direction.

A maximum of 8 mobile stations can share the same radio channel in the example shown.





TDMA OPERATION

0 01 12 23 34 45 56 67 7

Frame X Frame X + 1

MS 0

MS 1 MS 7

MS 5BaseStation





TDMA FRAME ORGANIZATIONFor Traffic Channels

ACCH Associated Control Channelch ChannelTDMA Time Division Multiple AccessTF TDMA FrameTS Time Slotms Millisecond





TDMA FRAME ORGANIZATIONFor Traffic Channels

3 57 1 26 1 57 3 8.25

Data Bits TrainingSequence Data Bits

0.577 ms Time Slot

Control Bits

TS

0

TS

0

TS

0

TS

1

TS

1

TS

1

TS

2

TS

2

TS

2

TS

3

TS

3

TS

3

TS

4

TS

4

TS

4

TS

5

TS

5

TS

5

TS

6

TS

6

TS

6

TS

7

TS

7

TS

7

TDMA Frame 4.615 ms

ch

ch

ch

ch

ch

ch

ch

ch

ch

ch

ch

ch

ch

ch

ch

ch

ch

ch

ch

ch

ch

ch

ch

ch

Slot 0 Slot 2 Slot 4 Slot 6

Frequency 1

Frequency 2

Frequency 124

TF

0

TF

1

TF

2

TF

11

TF

12

TF

22

TF

23

ACCH

ACCH

120 ms Multiframe

HeadBits

TailBits

GuardBits





MULTIPLEXING VOICE AND SIGNALINGUsing 13k bps Speech Coding





MULTIPLEXING VOICE AND SIGNALINGUsing 13k bps Speech Coding

0 3 4 5 6 71 2 0 3 4 5 6 71 2 0 3 4 5 6 71 2

Frame 0 Frame 1 Frame 2

Type of Information Transmitted/Received bya Mobile Station every 26 Frames (120 msec)

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

Voice

Voice

Voice

Voice

Voice

Voice

Voice

Voice

Voice

Voice

Voice

Voice

Associated Signaling

Voice

Voice

Voice

Voice

Voice

Voice

Voice

Voice

Voice

Voice

Voice

Voice

Idle (no transmission)

Frame#

Frame#

Slot#

Slot#

TrafficInformation

TrafficInformation





MULTIPLEXING 2 VOICE CALLSUsing 6.5k bps Speech Coding





MULTIPLEXING 2 VOICE CALLSUsing 6.5k bps Speech Coding

0 3 4 5 6 71 2 0 3 4 5 6 71 2 0 3 4 5 6 71 2


Type of Information Transmitted/Received bytwo Mobile Stations every 26 Frames (120 msec)

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

Voice (user 1)

Voice (user 2)

Voice (user 1)

Voice (user 2)

Voice (user 1)

Voice (user 2)

Voice (user 1)

Voice (user 2)

Voice (user 1)

Voice (user 2)

Voice (user 1)

Voice (user 2)

Signaling (user 1)

Voice (user 2)

Voice (user 1)

Voice (user 2)

Voice (user 1)

Voice (user 2)

Voice (user 1)

Voice (user 2)

Voice (user 1)

Voice (user 2)

Voice (user 1)

Voice (user 2)

Voice (user 1)

Signaling (user 2)

Frame#

Frame#

Slot#

Slot#

TrafficInformation

TrafficInformation

user 1

user 2





ISDN-LIKE CHANNEL STRUCTURERequires 6.5k bps Speech Coding





ISDN-LIKE CHANNEL STRUCTURERequires 6.5k bps Speech Coding

0 3 4 5 6 71 2 0 3 4 5 6 71 2 0 3 4 5 6 71 2


Type of Information Transmitted/Received by a Mobile Stationusing 2 B channels every 26 Frames (120 msec)

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

B1 channel

B2 channel

B1 channel

B2 channel

B1 channel

B2 channel

B1 channel

B2 channel

B1 channel

B2 channel

B1 channel

B2 channel

Associated signaling

B2 channel

B1 channel

B2 channel

B1 channel

B2 channel

B1 channel

B2 channel

B1 channel

B2 channel

B1 channel

B2 channel

B1 channel


Frame#

Frame#

Slot#

Slot#

TrafficInformation

TrafficInformation





CELLULAR CONCEPTS

A basic overview of cellular concepts is provided from Pages 1-55 through 1-73. If you areinterested in additional details, the article by V. MacDonald in the January 1979 Bell SystemTechnical Journal (BSTJ) is easy reading and provides more details. The entire January 1979 BSTJwas devoted to the AT&T Advance Mobile Phone Service (AMPS) system. The picture illustratedbelow is a copy of the BSTJ cover page which lists all the articles within the journal. While 1979may seem like a long time ago, basic cellular concepts have not changed much since then.

W. R. Young

V. H. MacDonald

Z. C. Fluhr andP. T. Porter

K. J. S. Chadha,C. F. Hunnicutt,S. R. Peck, andJ. Tebes, Jr.

G. A. Arredondo,J. C. Feggeler,and J. I. Smith

R. E. Fisher

J. T. Walker

N. Ehrlich,R. E. Fisher, andT. K. Wingard

S. H. Tsiang

G. C. DiPiazza,A. Plitkins, andG. I. Zysman

D. L. Huff

Introduction, Backgroundand Objectives

The Cellular Concept

Control Architecture

Mobile Telephone SwitchingOffice

Voice and Data Transmission

A Subscriber Set for theEquipment Test

A Service Set for theTelephone Control Unit

Cell-Site Hardware

Development Support Systems

The Cellular Test Bed

The Development System

Contributors to This Issue

Papers by Bell Laboratories Authors

1

15

43

71

97

123

145

153

201

215

249

271

277

THEBELL SYSTEMTECHNICAL JOURNAL

JANUARY 1979VOL. 58, NO. 1

ISSN0005-8580

ADVANCED MOBILE PHONE SERVICE




Cellular Concepts





SIMPLE NON-CELLULAR (NON-PRACTICAL)WIRELESS SYSTEM





SIMPLE NON-CELLULAR (NON-PRACTICAL)WIRELESS SYSTEM

PSTN

London

- One high-power transmit/receive tower in middle of London

- Assign all GSM frequencies to the one tower

- Maximum simultaneous calls = 992 (124 * 8)

Radio frequencycoverage area

Version 1.0.0November 20, 1991 -- 17:10:13 [djw1001.eps]




BASIC CELLULAR PRINCIPLES





BASIC CELLULAR PRINCIPLES

• Fixed spectral allocation limits the numberof channels that can be used

• Channels must be reused throughoutservice area to support service demand

• Signal attenuation with distance allowschannel reuse





CHANNEL REUSE

Radio channels can be reused provided the separation between cells containing the same channelset is far enough apart so that co-channel interference can be kept below acceptable levels most ofthe time.





CHANNEL REUSE

A

C

D G

F

A

B

B C D

F

E

E

G

A

B C

D E F

G

Channels divided into 7 channel sets A, . . . ,Gand reused throughout service area in three7-cell clusters





CHANNEL REUSE EXAMPLEUSING GSM FREQUENCIES

CLUSTER SIZE = 7





CHANNEL REUSE EXAMPLEUSING GSM FREQUENCIES

CLUSTER SIZE = 7

1 8

15 22 29 36

43 50 57 64

71 78 85 92

99 106 113

120 2 9

16 23 30 37

44 51 58 65

72 79 86 93100 107 114

121

3 10

17 24 31 38

45 52 59 66

73 80 87 94101 108 115

122

4 11

18 25 32 3946 53 60 67

74 81 88 95

102 109 116

123

5 12

19 26 33 4047 54 61 68

75 82 89 96

103 110 117

124

6 1320 27 34 41

48 55 62 69

76 83 90 97

104 111

118

1 8

15 22 29 36

43 50 57 64

71 78 85 92

99 106 113

120 2 9

16 23 30 37

44 51 58 65

72 79 86 93100 107 114

121

3 10

17 24 31 38

45 52 59 66

73 80 87 94101 108 115

122

4 11

18 25 32 3946 53 60 67

74 81 88 95

102 109 116

123

5 12

19 26 33 4047 54 61 68

75 82 89 96

103 110 117

124

6 1320 27 34 41

48 55 62 69

76 83 90 97

104 111

118

7 1421 28 35 42

49 56 63 70

77 84 91 98105 112

119

7 1421 28 35 42

49 56 63 70

77 84 91 98105 112

119





CELL COVERAGE AREA





CELL COVERAGE AREA

Theoretical Hexagon Coverage Area

Possible Real Cell Coverage AreaVersion 1.0.0

November 12, 1991 -- 14:55:05 [djw1002.eps]AT&T Proprietary − Use pursuant to Company Instructions



OTHER CELL CLUSTERS

The more cells in a cluster, the greater the separation between co-channel cells when other clustersare deployed. The idea is to keep co-channel cell separation the same throughout the system areafor cells of the same size. Some valid cluster sizes that allow this are: 1, 3, 4, 7, 9, 12, ....

Ericsson has been advertizing that a cluster size of 3 can be achieved while still maintaining anacceptable level of service quality.2

2 . Personal Communications based on Digital Cellular, Jan Swerup and Jan Uddenfeldt, Ericsson ReviewNo. 3, 1991.





OTHER CELL CLUSTERS

3-CellCluster

7-CellCluster

4-CellCluster

9-CellCluster





CELLULAR GROWTH THROUGHCELL SPLITTING

The example shown assumes that 14 cells were required at startup to cover a specified system area.Radio channels were assigned using a frequency reuse factor of 7. With continued subscribergrowth, three new small cells are added in the region shown.





CELLULAR GROWTH THROUGHCELL SPLITTING

Initiallayoutof 14 cells

(K = 7 reuse)

A

B

G D

E

F

G

E

G

B

A

C

C

E

G

C

E

G

E

B

E

G

B

A

Add 3new cellsto hightraffic area

AE

F

D

A CG





CONTINUED GROWTH

Growth continues as five more cells (including two that are at the next size smaller) are added to ahigh traffic region as shown. Notice that the cell with channel set F now serves a smaller area.





CONTINUED GROWTH

G

C

G

E

B

A

A

C

D

B

E

E

G

B D

Adding 8more cellsto hightraffic area

F

A CG

E

B

C





SECTORIZED ANTENNAS

As cell sizes are reduced, the propagation laws in force indicate that the levels of co-channelinterference will be received from six surrounding cells all using the same channel set. Therefore,one way of cutting significantly the level of interference is to use several directional antennas at thebase stations, which each antenna illuminating a sector of the cell, and with a separate channel setallocation to each sector. There are two commonly used methods of sectorization, using three 120degree sectors or six 60 degree sectors, both of which reduce the number of prime interferencesources to one. The three sector case is generally used with a seven-cell repeat pattern, giving anoverall requirement for 21 channel sets (reuse factor of 7 times 3 sectors). The improved co-channel rejection in the six sector case however, particularly the rejection of secondary interferers,results in a four-cell repeat pattern being possible, giving an overall requirement for 24 channel sets(reuse factor of 4 times 6 sectors).

A disadvantage of sectorization is that the larger channel sets required results in fewer channels persector, and thus a reduction in trunking efficiency. This means that the total traffic which can becarried for a given level of blocking is reduced. However, the ability to use much smaller cellsthrough sectorization greatly outweighs such drawbacks, and the end result is a much highercapacity system.





SECTORIZED ANTENNAS

Three Sector Coverage Area(120 degrees each sector)

0

10

20

30

40

50

6070

8090100110

120

130

140

150

160

170

180

190

200

210

220

230

240250

260 270 280290

300

310

320

330

340

350

Typical Radio Wave Propagation Pattern fora 120 Degree Antenna (viewed from top)

120 DegreeSector








Mobile Stations and Features





TYPES OF MOBILE STATIONS

Three basic types of mobile stations are defined:

1 . Vehicular stations

2 . Portable stations

3 . Handheld stations

Mobile stations can come in five power classes which define the maximum Radio Frequency (RF)power level that the unit can transmit:

Class Max RF Power (Watts)I 20II 8III 5IV 2V 0.8

Vehicular and portable units can be either class I or II, while handhelds can be class III, IV, or V.





TYPES OF MOBILE STATIONS

AvailablePowerClasses

Ior II

Ior II

IIIor IVor V

20w8w

20w8w

5w2w0.8

VehicularStations

Transmitter/Receiver

PortableStations

HandheldStations








Unit 2






GSM LAND-MOBILE NETWORKREFERENCE MODEL

• Standard open interfaces between entities, often referred to as network elements are defined inthe GSM Specifications. These interfaces are labeled: A, A-bis, B, C, D, E, F, G, and Um (orair interface).

• Interfaces not labeled with one of the above identifiers are not defined within the GSMspecifications.

• Since interfaces between network elements are open and standardized, a given serviceprovider has total flexibility in choosing and mixing different vendor’s equipment in theirnetwork.

• User information associated with a voice/data call between a mobile station and another entityin the PSTN/ISDN use the Um, Abis, A, and PSTN/ISDN interface. The PSTN/ISDNinterface are regulated at the national level and are outside the scope of the GSMrecommendations.

• All interfaces other than the ones listed in the previous bullet carry signaling message only(e.g., no voice circuits).





GSM LAND-MOBILE NETWORKREFERENCE MODEL

A

B

C

D

E F

G

Um

AUCBSCBSSBTSEIRHLRISDNMSMSCPSTNVLR

- Authentication Center- Base Station Controller- Base Station System- Base Transceiver Station- Equipment Identity Register- Home Location Register- Integrated Services Digital Network- Mobile Station- Mobile Switching Center- Public Switched Telephone Network- Visitor Location Register

AUC

HLR

VLR

VLR

EIR

In otherNetworks

MSC

OtherMSCs

BTS BSC

BSSAbis

MS

PSTN/ISDNNetwork

Version 1.0.0April 22, 1992 -- 18:33:24 [djw1091.eps]




GSM NETWORK MANAGEMENT ARCHITECTURE





GSM NETWORK MANAGEMENT ARCHITECTURE

MSC

BSS

ADC

NMC

AUC

HLR

VLR EIR

OMC

A

ADCAUCBSSEIRHLRMSCNMCVLR

- Administration Center- Authentication Center- Base Station System- Equipment Identity Register- Home Location Register- Mobile Switching Center- Network Management Center- Visitor Location Register





THE SS7 ARCHITECTURE

The SS7 protocol levels can be subdivided horizontally into two major parts: the lower part ortransport services part and the upper part or user part.

The MTP in the lower part provides a routing service for its users. It consists of three levels: thephysical, data link and network levels with corresponding OSI functionality. It uses in its level-3header level-3 addresses, the Signaling Point Codes (SPC) or Point Codes (PC) to forward "upperpart" messages to their destination in the network, that is, to select the next data link to forward themessage. Every network entity (STP, 4ESS, 1AESS, 5ESS, NCP), which may generate or receivean SS7 message is labeled with a Signaling Point Code (SPC), called Destination Point Code(DPC) or Origination Point Code (OPC) according to whether it is the destination or the origin of alevel-3 MTP message.

Note that a SS7-network user is considered to implement also OSI level 4 to 7 functionality. Thefact that the SS7 function is, in the greater scheme of things, a service function does not limit it interms of OSI functionality.

Other user parts like the Telephone User Part (TUP) and the Data User Part (DUP) are not shown inthe diagram. Their functions are provided in the ISDN-UP protocol.





THE SS7 ARCHITECTURE

Application

Presentation

Session

Transport

Network

Data Link

Physical

OMAP ASEs

TCAP

NULL

SCCP

MTP Level 3

MTP Level 2

MTP Level 1

transportservices

parts

ISDN-UP

userparts

OSI Model SS7 Protocol ModelCircuit relatedNon circuit related

OMAP

ASE

TCAP

ISDN-UP

SCCP

MTP

Operations Maintenance &Administration Part

Application Service Element

Transaction Capability Application Part

ISDN User Part

Signaling Connection Control Part

Message Transfer Part





BASE STATION SYSTEM (BSS) ARCHITECTURE

• A Base Station System (BSS) consists of one Base Station Controller (BSC) and a multipleBase Transceiver Stations (BTSs).

• Each BTS serves a cell area.

• A BTS consists of a controller, radio transmitter/receivers, RF amplifiers, RF combiners, anantenna, and much more.

• BTS equipment will most likely be co-located with the antenna. With the future need formicro-cells it will be necessary, however, to support antennas that can be remote from the restof the BTS control complex.

• A BSC manages resources and executes procedures that are common to all BTSs. If a BSC isequipped with a time-slot switching fabric, then a BSC can manage handovers between two ofits subordinate BTS without involving the MSC.

• BTSs are connected to a BSC over standard 32 channel digital facilities (operating at 2.048Mbps).

• A BTS can be only be connected to one BSC.

• There does not appear to be a specification within the GSM standards with respect to themaximum number of BTSs that can connect to one BSC (at least the author of this materialhasn’t stumbled across any requirements yet).

• A BSC is connected to a MSC also over standard 32 channel digital facilities.

• A BSC can only be connected to one MSC.

• A BSC can be physically positioned anywhere (geographically speaking) between a MSC andits BTSs.

• It is advantageous to cluster adjacent BTSs under the the same BSC to minimize the MSCinvolvement with handovers.





BASE STATION SYSTEM (BSS) ARCHITECTURE

BSS 1

A A

Cell

BSC1

BSC2

MSC

Abis Abis

Um

BTS BTS BTS





BSS - CONTINUED

BSS Base Station SystemBSC Base Station ControllerBTS Base Transceiver StationBCF Base Control FunctionTRX Transceiver

The BSC control one or more BTSs.

The BTS serves one cell in the cellular network and contains one or more TRXs.

The BCF handle common control functions within a BTS.

The TRX serves full duplex communications to the MS.

Version 1.0.0January 31, 1992 -- 18:24:52 [djw0694.txt]




BSS - CONTINUED

BSC

.

To MSC

A

To OMC

BCF

TRX•

•

BTS

BCF

TRX•

•

BTS

BSS

.

A-bis

• Responsible for communicating with mobile stations incell areas

• Radio equipment of a BSS may sustain one or morecells

• One BSC controls one or more BTSs

• One BTS serves one cell

Version 1.0.0June 1, 1992 -- 10:21:34 [djw0920.ped]




MOBILE-STATION/BASE-STATIONINTERFACE

The signaling protocol model for the "air" interface at the mobile station is shown. The physicallayer (L1) of this interface is also referred to as the radio subsystem layer. This layer interfaces tothe data link layer and the radio resource management sublayer in the Mobile Station (MS) andbase station, and to other functional units in the MS and network subsystem (which includes theBSS and the MSC) for supporting traffic channels. At the physical level, most signaling messagescarried on the radio path are in 23 octet blocks.

The GSM data link layer (L2) functions include link multiplexing, error detection and correction,flow control, and segmentation to allow for long messages on the upper layers. The protocol issimilar to ISDN LAPD and is called LAPDm.

The Radio Resource (RR) layer manages the dialog between the MS and BSS concerning themanagement of radio connections. It includes such things as connection establishment, control,release, and changes (e.g., during handover).

The Mobility Management (MM) layer deals with supporting such functions as location updating,authentication, and encryption management in a mobile environment.

In the Connection Management (CM) layer, the Call Control (CC) entity controls end-to-end callestablishment, and the Supplementary Services (SS) entity supports the management ofsupplementary services. Both protocols are very similar to those used in the fixed network.Finally, the Short Message Service (SMS) protocol of this layer supports the high level functionsrelated to the transfer and management of short message services.

Details on the MS to network interface are described in the GSM 04 series.





MOBILE-STATION/BASE-STATIONINTERFACE

MS BS

Signaling Protocol ReferenceModel at MS

CC SS SMS

L3

L2

L1

LAPDm

Physical Layer(radio subsystem)

Radio Resource Mangement (RR)

Mobility Management (MM)

Connection Management (CM)

Um

CCSSSMSLAPDm

Call Control entitySupplementary Services support entityShort Message Service support entityLink Access Procedures on Dm channel





MOBILE SERVICES SWITCHING CENTER (MSC)

Functions of the MSC include:

• Call handling that copes with mobile nature of subscribers (e.g., paging)

• Management of required logical radio-link channel during calls

• Management of MSC-BSS signaling protocol

• Control of inter-BSS handovers

• Acting as a gateway MSC to interrogate the HLR for routing incoming calls to the called MS

• Exchange of signaling information with other system entities

• Other normal functions of a local exchange switch in the fixed network

MSC interfaces with other network elements.

• An MSC typically controlled by one OMC.

• An MSC can be connected to only one VLR. Therefore, all mobile stations that move aroundunder base stations connected to the MSC are always managed by the same VLR.

• An MSC would communicate typically with one EIR. While it is possible for an MSC tocommunicate to multiple EIRs, this is highly unlikely since the EIR provides a centralized andgeographic independent function.

• The MSC consults an HLR to determine how a call should be routed to a given mobile station.For incoming calls to a mobile station, the MSC would typically consult one HLR. Formobile-to-mobile calls in larger networks, a MSC could consult HLRs of other systems tohelp minimize the trunk paths to the other mobile station.

• A given MSC can be interconnected to other MSC to support inter-MSC handovers. The Einterface is only a signaling interface and should not be confused as a voice path. How voicefacilities are connected between MSC are outside the scope of the GSM recommendations. Adetailed discussion on inter-MSC voice facilities is provided in the Handover Section in theCall Management Unit.





MOBILE SERVICES SWITCHING CENTER(MSC)

A

A

C

C

B

E E

F

HLR

HLR

VLREIR

MSC

OtherMSC

OtherMSC

BSS

BSS

OMC

PSTN/ISDNNetwork





BSS/MSC INTERFACE (A)

The physical layer of the A interface is a 2 Mbps (32 x 64 kbps) standard CCITT digitalconnection.

The signaling transport mechanism is handled by the MTP and SCCP parts of SS7. Error freetransport is handled by a subset of MTP and the logical connection is handled by a subset of SCCP.

The application parts of divided between BSSAP and BSSOMAP. The BSSAP is further dividedinto DTAP and BSSMAP. DTAP is in shape of transferring layer 3 messages between the MS andthe MSC without BSC involvement in the analysis. BSSMAP is responsible for all aspects of theradio resource handling at the BSS.

The BSSOMAP supports all the operations and maintenance communications of BSS.

See GSM 08 series for more details.





BSS/MSC INTERFACE (A)

MSC BSS

A

Signaling Protocol Reference Model

BSSAP

DTAP BSSMAP

BSSOMAPdistribution

SCCP

MTP Level 3

MTP Level 2

MTP Level 1

BSSAPDTAPBSSMAPBSSOMAPSCCPMTP

BSS Application PartDirect Transfer Appliation PartBSS Management Application PartOperations and Maintenance Application PartSignaling Connection Control PartMessage Transfer Part





MS-BTS-BSC-MSC SIGNALING PROTOCOL MODEL

CM Connection ManagementMM Mobility ManagementRR Radio Resource ManagementLAPD Link Access Procedures on D channelLAPDm Link Access Procedures on Dm channelBTSM BTS ManagementBSSAP BSS Application PartSCCP Signaling Connection Control PartMTP Message Transfer Part






MSUm

BTSA-bis

BSCA

MSC

Um

A

A-bis

Phys.

LAPDm

RRRR’

LAPDm

Phys.

BTSMLAPD

Phys. Phys.

LAPD

BTSM

RR’’

MTP

SCCP

BSSMAP

BSSMAP

SCCP

MTP

MM

CMCM

MM





HOME LOCATION REGISTER (HLR)

The Home Location Register (HLR) contains the identities of mobile subscribers (calledInternational Mobile Subscriber Identities or IMSIs), their service parameters, and their locationinformation. The location information is stored as a Mobile Station Roaming Number (MSRN)which is a directory number that the network can use to route calls to the Mobile Switching Center(MSC) where the mobile subscriber is located at the time of the call.






C

CDD

AUC

HLR

VLR VLR

MSC

MSCOMC

Identity of mobile subscriber

Directory number of mobile subscriber

Subscription information on teleservices

and bearer services

Service restrictions (if any)

Supplementary services

Contains:

Location information for call routingVersion 1.0.0

June 12, 1992 -- 13:04:12 [djw1132.eps]AT&T Proprietary − Use pursuant to Company Instructions



VISITOR LOCATION REGISTER (VLR)

The Visitor Location Register (VLR) contains the subscriber parameters and location informationfor all mobile subscribers currently located in the geographic area (i.e., cells) controlled by thatVLR. The VLR allocates the MSRN and (when required) a Temporary Mobile Subscriber Identity(TMSI) for secret identification of the mobile subscriber on the radio link.






B

G B

G

DD

VLR

HLR

VLR

VLR

HLR

MSC

MSC

OMC

Identity of mobile subscriber

Directory number of mobile subscriber

Copy of subscriber data from HLR

Contains:

Location area where mobile is registered

Temporary mobile subscriber identityVersion 1.0.0




EQUIPMENT IDENTITY REGISTER (EIR)

IMEI International Mobile Equipment Identity

This database is accessed during the equipment validation procedure when a mobile accesses thesystem. It contains the identities of mobile station equipments (IMEIs) which may be valid,suspect, or known to be fraudulent. In the GSM recommendations, the valid, suspect, andfraudulent list are referred to as the: white, gray and black lists.





EQUIPMENT IDENTITY REGISTER (EIR)

EIROMC

MSC

MSC

F

F

Contains:

Valid list

Suspect list

Fraudulent list

list of valid Mobile Equipment identities

list of Mobile Equipment identities underobservation

list of Mobile Equipment identities forwhich service should be barred





AUTHENTICATION CENTER (AUC)

• Since a GSM cellular system is based on a wireless access method, it is necessary for mobilestations to transmit their identity to the network. The purpose of an Authentication Center(AUC) is to generate authentication parameters that are used by Visitor Location Registers(VLRs) to make sure the identity transmitted by a mobile station is the correct identity and togenerate encryption/cipher keys that will be used to encrypt the radio path.

• The Operational Maintenance Center (OMC) interfaces with the AUC for administrationpurposes, such as adding/changing/deleting Authentication Keys (Ki).

• The only other network element that communicates with an AUC is the corresponding HomeLocation Register (HLR). No other network elements communicate with the AUC. If amobile station is visiting other networks, the VLR in the other networks communicate themobile station’s HLR. The HLR, in turn, retrieves information from the AUC and passes thisinformation to the requesting VLR.

• The AUC is a database that contains a unique Authentication Key (Ki) for each mobilesubscriber. The AUC also contains algorithms which generate authentication parameters.These algorithms can be CPU intensive.

• GSM does not define the interface between the HLR and AUC. Consequently, this interface isnot an open interface. The AUC can be viewed as an adjunct computer to the HLR, which hasbeen delegated the responsibility of managing authentication keys and generatingauthentication parameters.

• Most vendors will probably integrate the AUC and HLR. The main reason one might want toseparate the AUC from an HLR is to not burden an HLR with CPU intensive algorithms.

• The authentication process is discussed in more detail on Pages 3-82 and 3-84. Informationregarding encryption (cipher) key generation is provided on Page 3-88.





AUTHENTICATION CENTER (AUC)

. . . . . . . . . . . . . . . . .. . . . . . . . . . . .. . . . . . . .. . . . . . .. . . . . .. . . . .. . . . .. . . .. . . . .. . .. . . .. . . .. . .. . .. . .. . .. . .. . .. . .. . .. .. . .. .. . .. .. .. . .. .. .. .. .. .. . .. .. .. ... .. .. .. .. .. ... .. .. ... .. ... .. ... ... ... .. ... .. ... .. .. ... .. .. .. .. .. ... .. . .. .. .. .. .. .. .. . .. .. . .. .. . .. .. . .. . .. . .. . .. . .. . .. . .. . . .. . .. . . .. . . . .. . . .. . . . .. . . . . .. . . . . .. . . . . . . . .. . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . .. . . . . . . . . .. . . . . . . .. . . . . . .. . . . . . .. . . . . .. . . . .. . . . .. . . . .. . . . .. . . .. . . .. . . . .. . .. . . .. . . .. . .. . . .. . .. . . .. . .. . .. . .. . .. . .. . .. . .. . .. .. . .. . .. .. . .. .. . .. .. . .. .. . .. .. .. .. . .. .. .. .. . .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. . .. .. .. .. . .. .. .. . .. .. .. . .. . .. .. . .. . .. .. . .. . .. . .. . .. . .. . .. . . .. . .. . .. . . .. . . .

. . . .. . . .. . . .. . . . .. . . .. . . . .. . . . . .. . . . . .. . . . . . .. . . . . . . .. . . . . . . . .. . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . .

. ................. . . .. . . .. . . .. . . .. . . .. . . . .. . . . .. . . . .. . . . . .. . . . . . .. . . . . . .. . . . . . . . . .. . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . .. . . . . . . . . .. . . . . . .. . . . . . .. . . . . .. . . . .. . . . .. . . . .. . . .. . . .. . . .. . . .. . ................OMC AUC HLR

• Contains subscriber authentication datacalled Authentication Keys (Ki)

• Generates security related parametersneeded to authorize service using Ki

• Generates unique data pattern called aCipher Key (Kc) needed for encrypting userspeech and data





MOBILE APPLICATION PART (MAP)

Information transfer between GSM PLMN entities use the Mobile Application Part (MAP) of SS7.MAP consists of a Mobile Application and several Application Service Elements (ASEs). It usesthe services of the TCAP part of SS7. The mobile ASEs plus TCAP make up the MobileApplication Entity (AE) of SS7. It uses the SCCP for routing, and only Class 0 (connectionlessdatagram) service is required.

The MAP layers provide the necessary signaling functions needed to provide services such assetting up mobile facilities for voice and non-voice applications in a mobile network.





MOBILE APPLICATION PART (MAP)

ASE ASE• • •

TCAP

(MAP)

.Mobile Application Part

..........

..... .... ..... ........ ...................................................................................................................................................................................................................................................................................................................................................................

................................................................................................................................................................................................................................................................................................................................................................. ....... ..... .... ... ... ... .............

MobileApplicationEntity (AE)

SCCP

MTP L3

MTP L2

MTP L1

Version 1.0.0February 10, 1992 -- 21:52:15 [djw0911.ped]




MAJOR PROCEDURES SUPPORTEDBY MAP





MAJOR PROCEDURES SUPPORTEDBY MAP

• Location registration and cancellation

• Handover procedures

• Handling of supplementary services

• Retrieval of subscriber parameters duringcall set-up

• Authentication procedures





PUBLIC LAND MOBILE NETWORKS(PLMNs)

The following is the definition of a Public Land Mobile Network (PLMN) from the GSMrecommendations1

A Public Land Mobile Network (PLMN) is established and operated by anadministration or Registered Private Operating Agency (RPOA) for the specificpurpose of providing land mobile telecommunication service services to the public.A PLMN may be regarded as an extension of a network (e.g., ISDN); it is acollection of MSC areas within a common numbering plan (e.g., same NationalDestination Code) and a common routing plan. The MSCs are the functionalinterfaces between the fixed networks and a PLMN for call set-up.

Functionally, the PLMNs may be regarded as independent telecommunicationsentities even though different PLMNs may be interconnected through theISDN/PSTN Packet/Public Data Networks (PDNs) for forwarding of call or networkinformation. A similar tpe of interconnection may exist for the interaction betweenthe MSCs of one PLMN.

Presented on the following page is a simple example of two PLMNs. The size of a given PLMNcould be small (serve one city), consisting of one of each network element (AUC, HLR, VLR,MSC, and EIR). The largest size PLMN could serve an entire country and can consist of anynumber and combination of network elements. A PLMN does not cross country boundaries.

The GSM recommendations do not define the maximum capacity for each network element--this isa vendor specific detail. It is left up to each PLMN operator to purchase network elements fromone or more vendors and and properly engineer these network elements. There is not a one-to-onecapacity relationship between network elements. For example, a given vendor might provide aproduct line consisting of a 1000k subscriber HLR, 500k subscriber VLR, and 300k subscriberMSC. The PLMN operator would need to decide how many HLRs, VLRs and MSCs would berequired to meet their needs.

With regards to the diagrams on the following page, the solid lines between each network elementrepresent message communication signaling paths. The signaling path topology between networkelements is decided by the PLMN operator. One could have dedicated signaling paths betweeneach network element, use a PDN, or a combination of dedicated paths and the use of a PDN.

Not shown in the PLMN examples on the following page are Base Station Systems (BSSs) andOperation Maintenance Centers (OMCs), to keep the vu-graph from being too busy. BSSs andOMCs, of course, are essential components of a PLMN. A PLMN can consist of more than oneOMC.

1 . GSM Recommendation 03.02, Version 3.1.4, Section 2.5.

Version 1.0.0May 28, 1992 -- 13:45:34 [djw1007.txt]




PUBLIC LAND MOBILE NETWORKS(PLMNs)

A Public LandMobile Network

(PLMN)

Public SwitchedTelephone Network

(PSTN)

MSC MSC MSC

MSC MSC MSC MSC MSC

VLR VLR

VLRVLR

HLR

HLR

AUC

AUC

EIR

EIR

Signaling Network





GSM SYSTEM AREA(GSA)

A GSM System Area (GSA) is the entire coverage area where a GSM mobile subscriber canreceive wireless access from one or more GSM Public Land Mobile Networks (PLMNs).

Not to be confused with a GSM system area is the definition of a "GSM Service Area". This is thesum of all regions that a GSM subscriber can roam (including their home system area) and get callsfrom another party without the calling party knowing which region the subscriber happens to belocated.





GSM SYSTEM AREA(GSA)

GSMPLMNArea

GSMPLMNArea

GSMPLMNArea

GSMPLMNArea

GSA

GSM System Area (GSA)





SERVICE QUALITY REQUIREMENTS





SERVICE QUALITY REQUIREMENTS

• Time from switch-on to service ready:

4 sec in home system10 sec in visiting system

• Connect Time to called network:

4 sec• Release Time to called network:

2 sec• Time to Alert mobile of inbound call:

4 sec in 1st attempt15 sec in final attempt

• Maximum gap due to handover:

150 ms if intercell100 ms if intracell

• Maximum one-way speech delay:

90 ms

• Intelligibility of speech:

90%

Version 1.0.0February 3, 1992 -- 12:13:13 [djw0552.pic]




Version 1.0.0February 3, 1992 -- 12:13:13 [djw0552.pic]



Unit 3

Mobility Management




Mobility Management

UNIT OVERVIEW




Mobility Management

UNIT OVERVIEW

Mobile Station Registration Types

Detailed Location Registration Scenario

Routing Calls to Mobile Stations

Location Areas

Mobile Station Identification

Confidentiality and Security

Version 1.0.0July 2, 1991 -- 13:47:00 [djw0447.pic]



Mobility Management

GSM REFERENCE MODEL

The purpose of this unit is to present mobility management concepts for a cellular system based onthe GSM standard. All information presented and terminology used is based on the GSM referencemodel with the interfaces as illustrated on the following page.

The GSM standard is an open interface specification. In the standard, you’ll find details concerningthe sequence and format of messages exchanged across a given interface. For example, the "B"interface defines all messages and their organization between the Visitor Location Register (VLR)and the Mobile Switching Center (MSC). If a vendor was to provide a VLR and MSC as separatenetwork elements, as illustrated on the following page, then all messages exchanged between theVLR and the MSC must conform to the "B" interface specification.

The GSM standard allows for a vendor to combine/integrate several network elements into onenetwork element. When this is done, the interfaces between combined network elements are"internal" and do not need to conform to the GSM specification. For example, if a vendor was tointegrate the VLR with the MSC, then the vendor is not required to implement the "B" interface asdefined in the GSM specification.

To convey GSM mobility managements concepts to the fullest extent, it is assumed in this unit thatall network elements are implemented separately, thus requiring all interfaces as illustrated in thefollowing page.




Mobility Management

GSM REFERENCE MODEL

Abis

EIR

ISDN

PSTN

MSC

MSC

HLR



AUC

VLR

VLR

BSC

BTS

BSS

MS

F

E

C

A

B

G

D

Um

Version 1.0.0November 27, 1991 -- 14:17:56 [djw0428.pic]



Mobility Management

Version 1.0.0November 27, 1991 -- 14:17:56 [djw0428.pic]



Location Areas




Mobility Management

PAGING A MOBILE STATION

• Mobile stations, when powered on and idle (i.e, not engaged in a call), periodically scan a listof broadcast control channels looking for the channel with the strongest signal strength.

• Once a mobile station is locked onto a control channel, it listens for general system parametersand page messages that may be directed to the mobile station. One of the system parametersbeing broadcast, for example, is information indicating whether mobile stations are barredfrom using this base station to access the network.

• As a mobile station moves from one cell area to another, it will detect that the control channelassociated with a new cell area has a stronger signal than the current cell control channel. Itwill retune and lock its receiver to the new control channel.

• If a mobile station does not report its movements, Base Station Controllers (BSCs) and BaseTransceiver Stations (BTSs) will be unaware of a mobile station’s exact location.

• In order to deliver a call to a mobile station, a page message must be broadcast on the controlchannel from the BTS for which the mobile is currently monitoring.

• Multiple BTSs must be used to page a mobile station for situations where BSCs/BTSs areunaware of mobile station movement.

• If the mobile station hears its identification code broadcast on the paging channel, it willrespond with a page response message.




Mobility Management

PAGING A MOBILE STATION

MSCPSTN

MSC-BSS Trunks

Inter-office Trunks

BSC2 BSC

3

BSC1




Mobility Management

WHERE IS THE MOBILE STATION?

• One of the primary objectives of the GSM recommendations is to provide a standard thatsupports international roaming without requiring the calling party to be aware of the locationof the mobile subscriber; nor is the mobile subscriber required to notify anyone of her/hislocation in order to receive calls.

• Consequently, the network must be capable of delivering a call to a mobile station whether itis currently located in its home Public Land Mobile Network (PLMN) area, cities in othercountries, and/or possibly a competitor’s PLMN serving the mobile’s same home area.

• The difficulity in delivering a call to a mobile station is knowing which cell area should bepaged, and how many cell areas should be paged.

• One possibility would be to have all cells in Europe page a mobile station when delivering acall to a mobile subscriber.

• Involving too many cells in the paging process for call delivery can introduce performanceproblems.

Version 1.0.0July 7, 1992 -- 09:57:57 [djw1043.txt]



Mobility Management

WHERE IS THE MOBILE STATION?




Mobility Management

PAGING PERFORMANCE

• Paging performance problems can result if too many cell areas are paged when attempting todeliver a call to a Mobile Station (MS).

• As the page attempt rate increases to a given base station, eventually a resource becomes abottleneck.

• Most likely the limiting resource would the capacity of the paging channel, however, it is alsopossible to encounter other bottlenecks such as base station real-time. Each base station’spaging channels have a finite number of slots and transmission speed for broadcasting pageorders.

• Base station real-time might become a bottleneck if a base station is unable to perform othercall handling responsibilities because of the volume of pages that it is being asked tobroadcast.

• If a base station doesn’t have adequate overload controls, it is possible that the number ofsuccessful pages can start to decrease as the page attempt rate increases beyond the saturatedpoint.

• To keep the paging performance within a safe range, it is necessary to form regions/clusters ofcells and page only the cluster of cells for which the mobile is known to be situated. Theseclusters are referred as location areas.




Mobility Management

PAGING PERFORMANCE

Paging channelor Base Stationprocessing limit

SuccessfulTransmittedPages

Page Attempts

BaseStation

PagingMS A PagingMS B

PagingMS E PagingMS F

PagingMS C PagingMS D

Paging Channel




Mobility Management

LOCATION AREAS AND CELL AREAS

• A GSM Public Land Mobile Network (PLMN) area is divided into regions called LocationAreas (LAs).

• Each Location Area is made up of one or more Cell Areas.

• A Mobile Station is required to register each time it enters a new location area.

• Once registered, a Mobile Station is free to move around within the location area withoutregistering.

• When delivering a call to a mobile station, only one location area is paged. For example, if amobile station is known to be within Location Area 1, then all 59 cells representing LocationArea 1 will broadcast a page message to locate the mobile station.

• It is the responsibility of the Visitor Location Register (VLR) to manage location areas.

• Home Location Registers (HLRs) are unaware that geographic regions are divided intoLocation Areas.

• The term "geographic registration" is often associated with the concept of dividing a PLMNarea into regions whereby a mobile station automatically registers when it moves betweenlocation areas.

• In order for mobile stations to detect changes in location areas, every Base Transceiver Station(BTS), in every network, is required to broadcast on its broadcast control channel whatlocation area it represents. All BTSs, for example, that are associated with Location Area 1will be broadcasting a location area code that represents Location Area 1.

• As discussed previously, an idle mobile station (when powered up and not engaged in a call)is tuned to the strongest broadcast control channel. As a mobile station moves from one cellarea to another, it must compare the location area code being broadcast by the new BTS withthe location area where it last registered. If the location area values are different, the mobilestation will register.

• All mobile stations must be equipped with nonvolatile memory. After a mobile stationregisters in a given location area, it will write the location area code, associated with the newregistered area, to its nonvolatile memory.

• When a mobile station is powered-on (i.e., previously powered off), it will lock on to thestrongest cell broadcast control channel and then compare the location area code beingbroadcast with the value stored on its nonvolatile memory. If the values are different themobile station will register, otherwise the mobile will not register.

• The smallest possible location area size is equal to one cell, which of course is not practical.The volume of mobile station registrations increase as the size of location areas becomesmaller.

• The largest possible location area size is the total cell coverage area of one Mobile SwitchingCenter (MSC). See Page 3-20 for more details on MSC areas. The volume of page orders onpaging channels and the processing demands of BSSs increase as the size of location areasbecome larger.

• The optimal size of a location area depends on which resources become a bottleneck and/orwhich resources are most expensive.




Mobility Management

LOCATION AREAS AND CELL AREAS

LocationArea

1

LocationArea

2Location

Area3

LocationArea

4

LocationArea

5Location

Area6

LocationArea

7

VLR 1

VLR 2

CellArea

BorderbetweenVLRregions




Mobility Management

LOCATION AND CELL AREA IDENTIFICATION

Location areas, as described on previous page, are actually represented with a 3-field code knownas a Location Area Identification (LAI). Each of the 3-fields in an LAI consisting of: MobileCountry Code (MCC), Mobile Network Code (MNC), and Location Area Code (LAC), contributeto a hierarchy of information that can be used to qualify a given location area.1

The reason for the having a 3-field LAI structure is help insure that all Location Areas have aunique code.

Since the GSM recommendations is a multinational standard, the administration of unique LocationArea codes is simplified if the high-ordered field of an LAI is partitioned on a country basis andadministered by in international standards organization. MCCs are administered within CCITT.2

The allocation of NMCs is the responsibility of administration(s) within each country. If more thanone GSM Public Land Mobile Network (PLMN) exist in a country, a unique MNC should beassigned to each of them.

The LAC portion of the LAI is a flexible length code (up to 2 octets maximum) identifying alocation area within a PLMN. This part of the LAI can be coded using a full hexadecimalrepresentation, except an all zeros pattern which is reserved. This reserved value is use in somespecial cases when no valid LAI exists in mobile stations. The maximum number of location areaswithin a PLMN is 65535 (216 − 1), which is more than enough location areas codes even for a verylarge PLMN.

Also illustrated on the following page is the organization of a global cell identification. A globalcell identity consists of a LAI plus a 2 octet cell identity.3 With a global cell identity, every GSMcell in the world has a unique code. We will find out later in this course that a global cell identityis necessary for handing-over a call, for a given mobile station, between networks.

1 . Reference: GSM 3.03, Version 3.4.1, Section 4.1, Page 9.2 . Reference: GSM 3.03, Version 3.4.1, Section 2.3.3, Page 4.3 . Reference: GSM 3.03, Version 3.4.1, Section 4.2.1, Page 10.




Mobility Management

LOCATION AND CELL AREA IDENTIFICATION

Mobile Country Code(3 decimal digits)

Mobile Network Code(2 decimal digits)

Location Area Code(2 octets)

MCC MNC LAC

MCC MNC LAC CI

MCC

MNC

LAC

Cell Identity(2 octets)

CI

Cell Global Identification

Location Area Identification

Location Area Identification




Mobility Management

COUNTRY CODES AND MOBILE COUNTRY CODES

PARTIAL LIST

The following table lists a small percentage of the defined Country Codes (CC) and MobileCountry Codes (MCC) as defined in the CCITT recommendations.4 5

It is interesting to note that Mobile Country Codes are defined in the CCITT recommendations andnot in the GSM recommendations. MCCs have been defined for all countries in the world, not justthe European countries. Since the CCITT standards organization are responsible for internationalstandards, CCITT is the proper owner of Mobile Country Codes.

CCs are used by the PSTN to route international calls. MCCs have nothing to do with the PSTN.Any identity starting with a MCC should not thought of as phone number. MCCs are used strictlywithin PLMNs to support the following capabilities (not intended to be a complete list):

Determine where a given mobile station’s home PLMN resides.

• Determine which PLMN a given mobile station was previously registered.

• Help support handovers between PLMNs.

The author does not know exactly why a new numbering plan was introduced for mobiles (i.e.,MCCs) and why Country Codes are not sufficient. The author strongly suspects that the CCnumbering plan was too restrictive and that introducing a MCC numbering plan provided thenecessary flexibility. Notice that the United States has 7 MCCs and one CC. Could it be that 7MCCs were reserved with one MCC for each of the 7 Regional Bell Operating Companies(RBOCs)? The CC numbering plan has evolved over the years. Some countries have three digitCCs, others have two digits, and the United States has a one digit CC. MCCs are fixed length: 3digits.

Just because 7 MCCs have been reserved for the United States does not mean that the US has anyplans on adopting the GSM cellular standard. Standardizing MCCs for all countries in the worldhelps support the future possibility of mobile subscribers in a given Personal CommunicationNetwork (PCN) to visit PCNs in other countries and receive service even if the "terminal" (e.g.,GSM-TDMA, IS-54 TDMA, JDC-TDMA, CDMA, fixed exchange ISDN, etc ) access protocolaccess protocols are different between countries.

Again, do not confuse CC with MCC. MCCs are used to communicate information betweennetwork elements within a PLMN and between PLMNs. Mobile stations are assigned phonenumbers that conform to the international dialing plan, which uses CCs. To place an internationalcall to a mobile subscriber whose home is in the United Kingdom, one would have to specify "44"as the country code. The PSTN will never be offered a directory number that would start with aMCC, such as 234.

4 . CCITT Recommendation E.163 -- Numbering Plan for the International Telephone Service5 . CCITT Recommendation E.212 -- Identification Plan for Land Mobile Stations




Mobility Management

COUNTRY CODES AND MOBILE COUNTRY CODES

PARTIAL LIST

United Kingdom

Spain

France

Finland

Sweden

Italy

Netherlands

United States

Australia

Japan

Kuwait

44

34

33

358

46

39

31

1

61

81

965

234, 235

214

208

244

240

222

204

310 - 316

505

440, 441

419

CountryCode(CC)

CountryMobileCountryCode(MCC)




Mobility Management

MSC AREAS AND LOCATION AREAS

Illustrated previously was the relationship between cell areas and location areas. Here, therelationship between MSC areas and location areas is presented.

• As you should know, a location area is represented by a cluster of cell areas which share thesame location area identification.

• An MSC area is equal to the sum of all the cell areas associated with base stations connectedto the MSC. A base station can only be connected to one MSC.

• An MSC area may consist of one or several location areas.

• A location area, however, cannot exceed the size of an MSC area.

If, for example, a mobile station visits Location Area 234-06-02 under MSC 3, VLR 2 will processthe registration. Part of this registration process, which will be expanded in much more detail later,is to make sure that all calls to be delivered to the mobile station are routed to MSC 3. When a calldoes arrive to MSC 3, it will inform VLR 2 of an incoming call. VLR 2 will instruct MSC 3, inthis example, to have all base stations in Location Area 2 page the mobile station.

If the mobile station moves from location area 234-06-02, for example, to location area 234-06-01the mobile station will automatically register when it detects the change in location areas. VLR 2will receive the location registration from the mobile station via MSC 2. VLR 2 will executeprocedures which makes sure that all incoming calls for the mobile station are routed to MSC 2.




Mobility Management

MSC AREAS AND LOCATION AREAS

VLR 2VLR 1

LocationArea

LocationArea

LocationArea

LocationArea

LocationArea

MSC 1 MSC 2 MSC 3

MSC 1Area

MSC 2Area

MSC 3Area

234-05-01 234-05-03

234-05-02234-06-01 234-06-03

LocationArea

234-06-02

Version 1.0.0May 18, 1992 -- 21:09:55 [djw1060.eps]



Mobility Management

SUMMARY OF AREA RELATIONSHIPS

Cell Area

A cell is an area of radio coverage associated with a Base Transceiver Station (BTS). Each cell area has abroadcast control channel, a small pool of stand alone dedicated signaling channels, and hopefully a largepool of traffic channels. Idle mobile stations tune to the strongest broadcast control channel. It is over thischannel that mobile stations receive page messages.

Location Area

A location area is defined as an area in which a mobile station may move freely without registering. Alocation area may include one or several cell areas. All cells within a given location area transmit the samelocation area identification on their broadcast control channels. When delivering a call to a mobile station,all cells in the last known location area are paged.

MSC Area

The Mobile Switching Center (MSC) area is the part of the network covered by an MSC. This geographicarea is equal to the sum of all the cell areas associated with base stations connected to the MSC. A MSCarea may consist of one or several location areas. A location area, however, cannot exceed the size of anMSC area.

VLR Area

A mobile station roaming in an MSC area is controlled by the Visitor Location Register (VLR) in charge ofthis area. A VLR may be in charge of one or more MSC areas. An MSC area, however, cannot exceed thesize of a VLR area. A VLR is responsible for registering mobile stations as it moves between location areas.A VLR area may be divided into one or several location areas. Since the standard now assumes that theVLR and MSC are combined, the VLR area consists of one MSC area.

PLMN Area

A Public Land Mobile Network (PLMN) is established and operated by an administration or registeredprivate operating agency. A PLMN area is a collection of MSC areas within a common numbering plan(e.g., same National Destination Code) and a common routing plan. A PLMN area can consist of severalVLR areas. A country can consist of one or several PLMN areas. A PLMN area, however, cannot exceedthe size of a country.

GSM Service Area

The GSM service area is defined as an area in which a mobile station can be reached without the caller’sknowledge of the actual location of the mobile station. A GSM service area may consist of several PLMNareas. A GSM service area may consist of one country, be part of a country, or include several countries.Once a signaling network is deployed that allows all PLMNs to communicate between each other (which willtake many years for such a network to evolve) the GSM service area will be equal to summation of allregions that provide GSM service (i.e., all European countries and other non-European countries that deployGSM systems).

Version 1.0.0February 4, 1993 -- 13:29:20 [rjt1057.txt]



Mobility Management

SUMMARY OF AREA RELATIONSHIPS

CellArea

LocationArea

MSCArea

VLRArea

PLMNArea

CountryGSM

ServiceArea




Mobility Management

WHERE THE HLR FITS IN THE PICTURE

• The permanent copy of a give mobile subscriber’s service profile exists in only one place inthe world: a Home Location Register (HLR) in its home Public Land Mobile Network(PLMN).

• For example, lets assume we have an individual that is a resident of London who decides tosubscribe to cellular service. The individual would need to contact the service provider torequest service. The service provider would ask the individual which supplementaryservices/features the user desires and then would add a new entry to an HLR. The subscriber,of course, will request all of the expensive supplementary features!

• The diagram on the other page illustrates two HLRs in London. This is just an example.There could be one HLR in London or there could be ten HLRs in London. The number ofHLRs in a given city depends on factors such as: number of competing service providers inthe same area, whether HLRs are integrated within Mobile Switching Centers (MSCs), andsize of each system.

• Lets assume that information pertaining to the mobile subscriber is inserted into HLR 2 inLondon. The mobile subscriber will be given a phone number and a mobile station.

• If the mobile subscriber never turns on their phone, HLR 2 in London will be the only HLRdatabase in the world with information pertaining to the mobile subscriber. The process ofadding a new mobile subscriber to an HLR makes no assumption as to where the mobilestation will power up for the first time (i.e., where it will first perform a location update).Therefore, no Visitor Location Register (VLR) will be aware that the mobile station existsuntil the subscriber turns on his/her phone. If a new mobile subscriber never turns on theirphone (never takes the phone out of the box), no VLR will ever have information about thisparticular mobile subscriber. Assuming the service provider bills subscribers on a monthlybasis, the subscriber will receive monthly bills.

•The information passed between VLR and HLR is described by the procedures in RecommendationGSM 03.12.




Mobility Management

WHERE THE HLR FITS IN THE PICTURE

VLR 1 VLR 2 VLR 1 VLR 2 VLR

HLR HLRHLR 1

Paris

Paris

London

London

Rome

Rome

HLR 2

Signaling Network

208-12-1

208-12-2

208-12-3 208-12-4

208-12-5

208-12-6

208-12-7234-06-1

234-06-2

234-06-3

234-06-4234-06-5

234-06-6

234-06-7

234-06-8

234-06-9

Location Areas

222-06-1

222-06-2




Mobility Management




Mobile StationIdentification




Mobility Management

FIXED VS. MOBILE STATION DIRECTORY NUMBER TRANSLATION




Mobility Management

FIXED VS. MOBILE STATIONDIRECTORY NUMBER TRANSLATION

Local Switching Exchange

DN

PSTN

.........

MobileStation

FixedStation

........

....

Port

PSTN Location AreaMobile ID

DN

BSS

Location Area

Location Area

BSS

BSS

BSS

BSS

DN = Directory Number

Mobile Switching Center

DNPort

DN

Version 1.0.0March 15, 1992 -- 19:05:52 [djw0663.pic]



Mobility Management

MOBILE STATION

• A GSM Mobile Station (MS) consists of two parts: Mobile Equipment (ME) and a SubscriberIdentity Module (SIM). The SIM contains all network related subscriber information. TheME, which is the remaining part of a MS, realizes all the functions common to all GSMsubscribers.6

• In order for a mobile subscriber to place or receive a regular call, the user’s SIM must beinserted into the ME. It may be possible, at a network operator’s discretion, to allowemergency calls to be established from mobile equipment without a SIM.7

• If a SIM is removed from a mobile station while a call is in progress, the mobile equipmentinitiates an immediate release of the call.8 This is because the mobile equipment no longerhas any identity, the mobile subscriber is no longer reachable, and that the mobile subscriber’slocation is unknown.

• The interface between the SIM and ME is standardized. A user should be able to insert his/herSIM into any ME and be able to place or receive calls. All GSM subscribers must have aSIM. They are not required to purchase mobile equipment since the mobile equipment doesnot contain any subscriber information.

• For Integrated Circuit-card SIMs, its interface with the outside world is in accordance withInternational Standards Organization (ISO) standards on IC cards (ISO 7816 series). The SIMmay be part of a multi-service card, of which GSM mobile telecommunication is one of theapplications.9

• GSM also defines a Multi User Mobile Station (MUMS) whereby the mobile equipmentprovides multiple card reader slots, one per subscriber card. If the MUMS is busy by onesubscriber, another call to another subscriber having registered by means of the same MUMScannot be reached even though this person is not busy.10

6 . Additional information can be found in: GSM 02.17 (SIM, Functional Characteristics), and GSM 11.11(Specification of the SIM-ME Interface).

7 . Reference: GSM 02.03, Version 3.4.0, Teleservice 12 (Annex), Page 9.8 . Reference: GSM 2.17, Version 3.2.0, Section 3.2.1, Page 5.9 . Reference: GSM 02.17, Version 3.2.0, Section 2.2, Page 3.

10 . Reference: GSM 2.17, Version 3.3.0, Section 3.18, Page 15.




Mobility Management

MOBILE STATION

.

Mobile Station = Mobile Equipment + Subscriber Identity Module

MobileEquipment

SubscriberIdentityModule(SIM)




Mobility Management

MOBILE STATION IDENTIFICATION

International Mobile Subscriber Identity (IMSI)

• IMSI is assigned to a MS at subscription time

• IMSI uniquely identifies a given MS

• IMSI should only be transmitted over the radio path when necessary

MCC MNC MSIN

NMSI part

IMSI (15 digits)

MCC — Mobile Country Code [3 digits](home country)

MNC — Mobile Network Code [2 digits](home GSM PLMN)

MSIN — Mobile Subscriber IdentificationNumber

NMSI — National Mobile SubscriberIdentity

Temporary Mobile Subscriber Identity (TMSI)

• TMSI is assigned to a MS by the VLR

• TMSI uniquely identifies a MS within the area controlled by a given VLR

TMSI (32 bits max)

International Mobile Station Equipment Identify (IMEI)

• Uniquely identifies mobile station equipment

• Burnt in by the equipment manufacturer

TAC FAC SNR SP

IMEI (15 digits)

TAC — Type Approval Code (6 digits)

FAC — Final Assembly Code (2 digits)

SNR — Serial Number (6 digits)

SP — Spare (1 digit)




Mobility Management

MOBILE STATION IDENTIFICATION

Smart Card(SIM)

Jane Doe

International Mobile Equipment Identity (IMEI)

Mobile Station ISDN Number (MSISDN)

.

Temporary Mobile Subscriber Identity (TMSI)International Mobile Subscriber Identity (IMSI)




Mobility Management

SUBSCRIBER IDENTITY MODULE(SIM)

Types of information contained in SIM:

• International Mobile Subscriber Identity (IMSI)

• Authentication key (Ki)

• Personal Identification Number (PIN)

• Subscriber information

• Access control class

• Cipher key (Kc)∗• Temporary Mobile Station Identification (TMSI)∗• Additional GSM services∗• Location Area Identity (LAI)∗• Forbidden Public Land Mobile Networks (PLMNs)∗

* Updatable by network

The possibility exists that a Mobile Station (MS) with a plug-in Subscriber Identity Module (SIM)may also have provision for accepting an Integrated Circuit (IC) card. In this case, the IC cardtakes precedence over the plug-in SIM. If the IC card is inserted during a call, the IC card will takeprecedence after the call has finished. If the IC card is removed then the plug-in SIM takes over thesecurity function. If an IC card is removed during a call, the call is terminated.11

11 . Reference: GSM 2.17, Version 3.2.0, Section 5, Page 10.




Mobility Management

SUBSCRIBER IDENTITY MODULE(SIM)

SIMCard

IC Card Type SIM

MobileEquipment

MobileEquipment

Plug-InType SIM

Mobile Station = Mobile Equipment + SIM




Mobility Management


The Home Location Register (HLR) is a data base in charge of the management of mobilesubscribers. A Public Land Mobile Network (PLMN) may contain one or several HLRs: it dependson the number of mobile subscribers, on the capacity of the equipment and on the organization ofthe network.12 The two most noteworthy pieces of information stored in the HLR are:

• Permanent copy of mobile subscriber’s subscription information.

• Some location information enabling the routing of calls towards the MSC where the mobilestation is located (VLR address).

All administrative interventions concerning a given mobile subscriber occur on the HLR. Thisdatabase is used for routing of calls to mobile subscribers managed by this HLR. The HLRs haveno direct control of Mobile Switching Centers (MSC)s.

There are two numbers that serve as primary keys into the HLR database:

• International Mobile Station Identity (IMSI)

• Mobile Station International ISDN number (MSISDN)

The database contains other information such as:

• Teleservices and bearer services subscription information

• Service restrictions (e.g., roaming limitations)

• Supplementary service parameters

More information can be found about HLRs in the following sections of the GSM specification:Organization of Subscriber Data: GSM 03.08Home Location Register Specification: GSM 11.31





Mobility Management


MSISDN

IMSI

x

x

- Subscriber Data- IMSI- MSISDN- VLR Address

x

KEYS:

CONTAINS:


Mobile Subscriber ISDN Number (MSISDN)

Subscriber data

IMSI

MSISDN

VLR Address




Mobility Management


According to the GSM specifications a mobile station is always viewed as a "visitor." If the mobilestation is in its home Mobile Switching Center (MSC) area, the mobile is simply visiting home.All MSCs have one Visitor Location Register (VLR), which can be integrated within the MSC orcan be a separate network element.

The VLR contains the necessary information needed to handle calls while a mobile station isvisiting its controlled area.

The information passed between VLR and HLR is described by the procedures in RecommendationGSM 03.12. The organization of subscriber data is detailed in Recommendation GSM 03.08. TheVisitor Location Register specification can be found in Recommendation GSM 11.32.

Version 1.0.0December 11, 1991 -- 16:21:49 [djw0443.txt]



Mobility Management


TMSI

IMSI

MSRN

x

x

x x

KEYS:

CONTAINS:


Mobile Station Roaming Number (MSRN)

Temporary Mobile Subscriber Identity (TMSI)

Subscriber data

IMSI

MSISDN

Location Area Code (LAC) of Mobile Station

TMSI

- Subscriber Data- IMSI- MSISDN- LAC- TMSI




Mobility Management

LOCATION UPDATE EXAMPLE

First Time

This must be done prior to the first phone call (incoming or outgoing), with the single exception ofemergency calls which are to be setup even if the subscriber is not registered.

0 The subscriber has signed up with a service provider and has been provided with a SIM cardand MSISDN. The Mobile Subscriber’s data has been entered into the service provider’s HLRdatabase.

1 The Mobile Subscriber has turned the phone on and the phone notices that the Location AreaIdentification (LAI) in the broadcast does not match the LAI on the SIM. (In this case the LAIon the SIM is null since this is the very first use of this SIM.) The mismatch in the LAIstriggers the MS to initiate a Location Registration. The Location Update message from theMS contains the IMSI and old LAI. The BSS then adds the new LAI in the header of themessage before it passes it onto the MSC.

2 The VLR gets the Location Update information from the MSC and determines that it mustretrieve subscriber data from the HLR. The VLR uses the IMSI to determine which HLRshould be queried for this subscriber.

3 The VLR send a MAP message to the HLR requesting subscriber data for the subscriberidentified by the IMSI.

BSS - Base Station SystemCC - Country CodeHLR - Home Location RegisterIMSI - International Mobile Subscriber IdentityLAI - Location Area IdentificationLU - Location UpdateMAP - Mobile Application PartMCC - Mobile Country CodeMS - Mobile Subscriber or StationMSC - Mobile Switching CenterMSISDN - Mobile Station ISDN numberSIM - Subscriber Identity ModuleVLR - Visitor Location Register




Mobility Management


First Time

IMSI = 234-02-1234567MSISDN = 44-75-555-1212

IMSI = 234-02-1234567

Registration(IMSI = 234-02-1234567)

(LAI (old) = NULL)BSS Header:

(LAI (new) = 208-06-=01)

1

0

2

3Update Location

(IMSI = 234-02-1234567)

PARIS

London

VLR

HLR

Subscriber DataVLR Adr = NULL

MSC

BSS1

BSS2

LAI = 208-06-01




Mobility Management


First Time -- Continued

4 The HLR checks the subscriber’s permissions to ensure roaming is allowed and stores theVLR address for future use (i.e., mobile terminations and future roaming to new VLR areas.)

5 The HLR sends a MAP message to the VLR with the subscriber’s data.

6 The VLR builds a subscriber record and stores the new LAI with that record. Anacknowledgment of the receipt and writing of the subscriber data is sent to the HLR.

6a The HLR signals Update Location Complete.

7 The VLR assigns a TMSI to this subscriber. (This step is optional and is at the discretion ofthe service provider.)

8 The VLR/MSC sends a message to the MS accepting the Location Update request andassigning the TMSI for the MS.

BSS - Base Station SystemCC - Country CodeHLR - Home Location RegisterIMSI - International Mobile Subscriber IdentityLAI - Location Area IdentificationLU - Location UpdateMAP - Mobile Application PartMCC - Mobile Country CodeMS - Mobile Subscriber or StationMSC - Mobile Switching CenterMSISDN - Mobile Station ISDN numberSIM - Subscriber Identity ModuleTMSI - Temporary Mobile Subscriber IdentityVLR - Visitor Location Register

Version 1.0.0March 3, 1993 -- 16:43:35 [rjt1064.txt]



Mobility Management


First Time -- Continued

Registration Accepted(TMSI = 6666)

(LAI = 208-06-01)

8

4

7

5

IMSI = 234-02-1234567TMSI = 6666

IMSI = 234-02-1234567MSISDN = 44-75-555-1212

Update Complete

PARIS

London

VLR

HLR

MSC

BSS1

BSS2

LAI = 208-06-01

6Subscriber DataLA = 01

VLR Adr = ParisSubscriber Data

6

Subscriber Data

Subscriber DataAcknowledge

6a




Mobility Management


Movement within VLR Area

Location Updates are never done during a phone call. Movement between Location Areas (actuallybetween BSSs) during a phone call are covered in the Handover portion of section 4.

1 The Mobile Station notices that the Location Area Identification (LAI) in the strongestbroadcast channel does not match the LAI on the SIM. The mismatch in the LAIs triggers theMS to initiate a Location Update. The Location Update message from the MS contains theTMSI and old LAI. The BSS then adds the new LAI in the header of the message before itpasses it onto the MSC.

2 The VLR gets the Location Update information from the MSC and determines the MS haspreviously registered in this VLR area, but the LAI changes. The VLR updates the LAI forthis subscriber in the VLR record.





Mobility Management


Movement within VLR Area

Registration(TMSI = 6666)

(LAI(old) = 208-06-01)BSS Header:

(LAI(new) = 208-06-20

1

IMSI = 234-02-1234567TMSI = 6666

IMSI = 234-02-1234567MSISDN = 44-75-555-1212

PARIS

London

VLR

HLR


2Subscriber DataLA = 20

LAI = 208-06-01

BSS3

LAI = 208-06-20

BSS4




Mobility Management


Movement within VLR Area -- cont.

3 The VLR assigns a new TMSI to this subscriber. (This step is optional and is at the discretionof the service provider.)






Mobility Management


Movement within VLR Area -- cont.


(LAI = 208-06-20)

4

3IMSI = 234-02-1234567TMSI = 7777

IMSI = 234-02-1234567MSISDN = 44-75-555-1212

PARIS

London

VLR

HLR


LAI = 208-06-01

BSS3

LAI = 208-06-20

BSS4

Subscriber DataLA = 20 2




Mobility Management


Movement between VLRs

1 The Mobile Station notices that the Location Area Identification (LAI) in the strongestbroadcast does not match the LAI on the SIM. The mismatch in the LAIs triggers the MS toinitiate a Location Registration. The Location Update message from the MS contains theTMSI and old LAI. The BSS then adds the new LAI in the header of the message before itpasses it onto the MSC.

2 The VLR gets the Location Update information from the MSC and determines from the oldLAI that the TMSI does not identify a VLR record on this system. In order to retrieve theIMSI, which is necessary to query the HLR, the VLR queries the old VLR for the IMSI usingthe TMSI. It is optional to request Authentication data at this time also.

3 The old VLR responds with the IMSI and Authentication data if requested. If steps 2 and 3fail for any reason, the VLR/MSC can query the MS for the IMSI directly. However, this isthe last resort since the intent is to not transmit the IMSI across the Air interface to the extentpossible.

4 Once given the IMSI, the new VLR can determine the MS’s HLR.

5 The VLR send a MAP message to the HLR requesting subscriber data for the subscriberidentified by the IMSI.





Mobility Management


Movement between VLRs


(LAI(old) = 208-06-20)BSS Header:

(LAI(new) = 222-03-68)

Need IMSI(TMSI = 7777)

Optional:Ask for Authentication

Parameters tooUpdate Location

(IMSI = 234-02-1234567)

IMSI Response(IMSI = 234-02-1234567)

1

4

IMSI = 234-02-1234567TMSI = 7777

IMSI = 234-02-1234567

IMSI = 234-02-1234567MSISDN = 44-75-555-1212

PARIS

ROME

London

VLR

VLR

HLR


BSS3

BSS8

LAI = 208-06-20

LAI = 222-03-68

BSS4

BSS5

Subscriber DataLA = 20

2

5

3




Mobility Management


Movement between VLRs -- cont.

6 The HLR checks the subscriber’s permissions to ensure roaming is allowed and stores the newVLR address for future use (i.e., mobile terminations and future roaming to new VLR areas.)

7 The HLR sends a MAP message to the VLR with the subscriber’s data. The VLR writes thesubscriber’s data to a new VLR record.

7a Assuming the VLR record was built with no problems, the VLR acknowledges the subscriberdata receipt.

7b The HLR acknowledges the Update Location is complete.

8 The HLR notifies the old VLR the MS has registered in a new VLR area and the record at theold VLR should be deleted.

9 The VLR builds a subscriber record and stores the new LAI with that record. Also, the VLRassigns a TMSI to this subscriber. (This step is optional and is at the discretion of the serviceprovider.)



Version 1.0.0March 3, 1993 -- 16:41:16 [rjt1068.txt]



Mobility Management


Movement between VLRs -- cont.


(LAI =222-03-68)

Update Complete

Delete Record(IMSI = 234-02-1234567)

10

9

IMSI = 234-02-1234567TMSI = 7777

IMSI = 234-02-1234567TMSI = 8888

IMSI = 234-02-1234567MSISDN = 44-75-555-1212

PARIS

ROME

London

VLR

VLR

HLR

VLR Adr = RomeSubscriber Data

BSS3

BSS8

LAI = 208-06-20

LAI = 222-03-68

BSS4

BSS5

Subscriber Data

Subscriber Data

LA = 20

LA = 68

6

8

Subscriber Data

7a Subscriber DataAcknowledge

7b

7




Mobility Management




Routing Callsto Mobile Stations




Mobility Management

MOBILE STATION ROAMING NUMBER (MSRN)

MSC - Mobile Switching CenterMSISDN - Mobile Station ISDN numberMSRN - Mobile Station Roaming NumberPSTN - Public Switched Telephone Network




Mobility Management

MOBILE STATION ROAMING NUMBER (MSRN)

PSTN...................

LocalExchange

MSISDN

............

MSISDN

MSISDN

MSISDN

.............

MSRN...........

..........

VisitedMSC

HomeMSC




Mobility Management

MSC DIRECTORY NUMBER ALLOCATION

MSC - Mobile Switching CenterMSISDN - Mobile Station ISDN numberMSRN - Mobile Station Roaming NumberPSTN - Public Switched Telephone Network




Mobility Management

MSC DIRECTORY NUMBER ALLOCATION

Directory Number Spectrum

MSISDN

PSTN

MSC

MSC

LOCALEXCHANGE

Trunks

Trunks

MSRN Used to referencevisiting subscribers

Used to referencehome subscribers

Version 1.0.0May 23, 1991 -- 13:31:19 [djw0602.pic]



Mobility Management

LAND TO MOBILE CALL ROUTING

Mobile Located in Non-Home MSC Area

The following diagram shows an example of call routing and signaling paths for a mobile stationterminated call. The MSRN allocation described in this scenario is called per call MSRNallocation. Another option in the standards, but not supported by any known service providers, isthe per registration MSRN allocation. In the second case, the MSRN is stored at the HLR for theentire time the MS is registered in a VLR area. This allows the network to skip steps 4 and 5, butrequires a very large number of MSRNs.

1 A user on a land-line phone dials the MSISDN of a Mobile Subscriber.

2 The PSTN, using normal digit analysis, routes the call to the home PLMN/MSC of the MobileSubscriber.

3 The home MSC does digit analysis and notes that this number is an MSISDN for a MS. AMAP routing query for this MSISDN is sent to the MS’s HLR.

4 The HLR sends a MAP routing query for this IMSI (MSISDN to IMSI translation done in theHLR) to the last known VLR address.

5 The VLR assigns a temporary MSRN associated with this IMSI and sends the MSRN back tothe HLR.

6 The HLR passes the MSRN onto the home MSC.

7 The home MSC reroutes the call using the MSRN. Normal digit analysis on the home MSCindicates that calls with this MSRN should be routed to the PSTN.

8 Normal digit analysis within the PSTN indicates that this MSRN should be routed to thevisited MSC.

9 When the incoming call with this MSRN arrives at the MSC, the MSC digit analysisrecognizes it as an MSRN and asks the VLR for the MS associated with this MSRN.

10 The VLR retrieves the associated VLR record (TMSI, last reported LAI, etc.) and releases theMSRN for future use.

11 The MSC sends page requests to the BSS(s) in the LAI.

12 The BSS(s) page for the Mobile.

BSS - Base Station SystemHLR - Home Location RegisterIMSI - International Mobile Subscriber IdentityMAP - Mobile Application PartMSC - Mobile Switching CenterMSISDN - Mobile Station ISDN numberMSRN - Mobile Station Roaming NumberTMSI - Temporary Mobile Subscriber IdentityPSTN - Public Switched Telephone NetworkVLR - Visitor Location Register




Mobility Management


Mobile Located in Non-Home MSC Area

PSTN

HomeMSC

VisitedMSC

BSS 2

BSS 2

BSS 1

BSS 1

MSRN

MSI

SDN

MSR

N

IMSIMSRN

MSISD

N

Voice Path

Signaling

1

2

8

7

45

HLR

VLR

HomePLMN

VisitedPLMN

MSRN

9TMSI

&LAC

10

11

TMSI

12

TMSI

Gateway MSC

3 6

MSISDN MSRN




Mobility Management


Mobile in Home MSC Area

The following diagram shows an example of call routing and signaling paths for a mobile stationterminated call within the Home MSC area..


2 The PSTN, using normal digit analysis, routes the call to the home PLMN/MSC of the MobileSubscriber.

3 The home MSC does digit analysis and notes that this number is an MSISDN for a MS. AMAP routing query for this MSISDN is sent to the MS’s HLR.

4 The HLR sends a MAP routing query for this IMSI (MSISDN to IMSI translation done in theHLR) to the last known VLR address. (In this case, the last known VLR address is in thisPLMN.)


6 The HLR passes the MSRN onto the home MSC.

7 The home MSC reroutes the call using the MSRN. Normal digit analysis on the home MSCindicates that calls with this MSRN are terminated on this MSC.




The MSRN allocation described in this scenario is called per call MSRN allocation. Another optionin the standards, but not supported by any known service providers, is the per registration MSRNallocation. In the second case, the MSRN is stored at the HLR for the entire time the MS isregistered in a VLR area. This allows the network to skip steps 4 and 5, but requires a very largenumber of MSRNs.

BSS - Base Station SystemHLR - Home Location RegisterIMSI - International Mobile Subscriber IdentityMAP - Mobile Application PartMSC - Mobile Switching CenterMSISDN - Mobile Station ISDN numberMSRN - Mobile Station Roaming NumberTMSI - Temporary Mobile Subscriber IdentityPLMN - Public Land Mobile NetworkPSTN - Public Switched Telephone NetworkVLR - Visitor Location Register




Mobility Management


Mobile in Home MSC Area

PSTN

VLR

BSS 2

BSS 1

MSR

NTM

SI&

LAC

TMSI

TMSI

HLR

MSISDN

MSRN

MSISDN

MSISD

N

Voice Path

Signaling

HomeMSC

1

2

3 6

8

9

10

7

5

4IMSI

MSRN




Mobility Management


Via Gateway MSC

The following diagram shows an example of call routing and signaling paths for a mobile stationterminated call with a Gateway MSC in the Home PLMN.


2 The PSTN, using normal digit analysis, routes the call to the home Gateway MSC in the homePLMN.

3 The Gateway MSC does digit analysis and notes that this number is an MSISDN for a MS. AMAP routing query for this MSISDN is sent to the MS’s HLR.

4 The HLR sends a MAP routing query for this IMSI (MSISDN to IMSI translation done in theHLR) to the last known VLR address. (In this case, the last known VLR address is in thisPLMN.)


6 The HLR passes the MSRN to the Gateway MSC.

7 The Gateway MSC routes the call using the MSRN.










Mobility Management


Via Gateway MSC

PSTN

VisitedMSC

BSS 2

BSS 2

BSS 1

BSS 1

MSISDN

MSISDN

Voice Path

Signaling

1

2

HLR

VLR

MSRN

8TMSI

&LAC

9

10

TMSI

11

TMSI

MSC

Gate-way

HomeMSC

HomePLMN

MSRN

7

MSR

N

MSIS

DN

MSRNIMSI6

45

3




Mobility Management


Intelligent PSTN

The following diagram shows an example of call routing and signaling paths for a mobile stationwith an Intelligent PSTN. The Intelligent PSTN supports the identification of an MSISDN, theMAP query of the HLR, and the rerouting of the call based on the MSRN.


2 The PSTN, using normal digit analysis, notes that this number is and MSISDN for a MS. AMAP routing query for this MSISDN is sent to the MS’s HLR.

3 The HLR sends a MAP routing query for this IMSI (MSISDN to IMSI translation done in theHLR) to the last known VLR address.


5 The HLR passes the MSRN to the Intelligent PSTN.

6 The Intelligent PSTN reroutes the call using the MSRN. Normal digit analysis indicates thatcalls with this MSRN are routed to the visited MSC.










Mobility Management


Intelligent PSTN

PSTN

HomeMSC

VisitedMSC

BSS 2

BSS 2

BSS 1

BSS 1

MSRN

MSISDN

MSRN

IMSIMSRN

MSISD

N

Voice Path

Signaling

1

2

6

5

34

HLR

VLR

HomePLMN

VisitedPLMN

MSRN

7TMSI

&LAC

8

9

TMSI

10

TMSI




Mobility Management




Mobile StationRegistration Types




Mobility Management

3 TYPES OF MOBILE STATION REGISTRATION




Mobility Management

3 TYPES OF MOBILE STATION REGISTRATION

• GEOGRAPHIC Based

• TIME Based

• ON/OFF Based




Mobility Management

GEOGRAPHIC BASED REGISTRATION

Each cell area is served by a Base Transceiver Station (BTS). Each BTS transmits on its broadcastcontrol channel the Location Area Identification (LAI) that it represents. As a mobile stationmoves from one cell area to another, it retunes to a new broadcast control channel. Each time themobile station retunes, it compares the LAI received to the last registered LAI, stored on theSubscriber Identity Module (SIM). If the two LAIs are different, the mobile station executes alocation update procedure.

LA - Location Area

MSC - Mobile Switching Center

VLR - Visitor Location Register




Mobility Management

GEOGRAPHIC BASED REGISTRATION

VLR

MSC

LA 1

LA 1

LA 1 LA 2

LA 2

LA 2

LA 2




Mobility Management

TIME BASED REGISTRATION

Mobile periodically registers. Updates depend on mobile station activity. Update intervals arebroadcast by base stations.

Note:

• Units of 1 deci-hours

• Minimum Interval: 6 minutes (1 deci-hour)

• Maximum Interval: 25.5 hours (255 deci-hours)

• Timeout value sent on broadcast channels to mobiles

• Timeout value can be set to infinity




Mobility Management

TIME BASED REGISTRATION

TIMER MANAGEMENT:

• Timer is reset when mobile station activityhas taken place

• Mobile station initiates location updatingwhen timer expires

• Mobile station timer value is kept in memorywhen turned off




Mobility Management

ON/OFF BASED REGISTRATION

The term "ON/OFF Based Registration" is NOT a term used in the GSM standards, and is usedhere to help convey a concept. As you might suspect, ON refers to the mobile station beingpowered on and OFF refers to the mobile station being powered off. The terms "InternationalSubscriber Identity (IMSI) attach" and "IMSI detach" are used in the GSM standard.

The IMSI detach operation is the action taken by a mobile station to indicate to the Public LandMobile Network (PLMN) that the station has entered an inactive state (e.g, the station is powereddown or the Subscriber Identity Module (SIM) has been removed). The IMSI attach operation isthe action taken by a mobile station to indicate to the PLMN that the station has reentered an activestate (e.g., the station is powered up and/or that a SIM card has inserted into the mobileequipment).13 The support of the IMSI attach/detach operation is mandatory in mobile stations.The activation and implementation of this capability is optional within the fixed infrastructure of aPLMN.

When a mobile station is powered on (or SIM card inserted), the mobile station will first check tosee if it is still in the same location area. If the mobile has entered a new location area, it willperform the procedure associated with geographic registration (and no IMSI attach message will besent).14 If the mobile has not moved into a new location area, it will perform an IMSI attachoperation only if the PLMN operator has this capability activated. Information transmitted on the"broadcast control channel" from each Base Transceiver Station (BTS) tells mobile stationswhether IMSI attach/detach is supported.

The IMSI detach signal sent from the mobile station to the MSC is not acknowledged.

The IMSI attach signal sent from the mobile station is acknowledged from the MSC. If theacknowledgement indicates that the mobile station is not registered or that the mobile station’sidentification is not sufficient (i.e TMSI), the mobile station will execute its normal locationregistration procedure.

Details concerning whether a mobile station is available or unavailable in a PLMN is usefulinformation to a VLR, especially with regards to delivering calls to a mobile station. If a mobilestation is known to be unavailable (marked as deatached), and a call is to be delivered to it, theVLR will not request that the Mobile Switching Center (MSC) page the mobile station in its lastregistered location area. Instead, the calling party will possibly be connected to an appropriateannouncement (e.g., "were sorry, the mobile subscriber that you have dialed is unavailable") orredirected to another directory number.

13 . Reference: GSM 3.12, Version 3.1.4, Section 2.4, Page 3.14 . Reference: GSM 3.12, Version 3.1.4, Section 3.6, Page 7.




Mobility Management

ON/OFF BASED REGISTRATION

• IMSI ATTACH– mobile power-up = attach– mobile power-up causes a location

update with type=attach

• IMSI DETACH– mobile power-down = detach– mobile power-down causes a flag on

the VLR record to prevent paging

Version 1.0.0February 4, 1993 -- 16:27:01 [rjt0678.pic]



Mobility Management




Confidentiality andSecurity




Mobility Management

CONFIDENTIALITY & SECURITY MECHANISMS




Mobility Management

CONFIDENTIALITY & SECURITY MECHANISMS

• Use of TMSI instead of IMSI

• Mobile Station Authentication

• Encryption of information on the radio path

• Mobile Equipment validation

Version 1.0.0April 3, 1992 -- 21:45:11 [djw0679.pic]



Mobility Management

WHY AUTHENTICATE?

One of the major problems for the Analog Cellular providers has been fraudulent users. Hackersreplicate the identity of legitimate mobile stations so they can make long distance phone calls at nocharge. One of the advantages of the digital systems is the message oriented protocol supports agreater ability to protect and authenticate the subscriber identity.




Mobility Management

WHY AUTHENTICATE?

IMSI/TMSI

HackerShack




Mobility Management

SUBSCRIBER IDENTITY AUTHENTICATIONAND CIPHERKEY SETTING

Activities that may trigger authentication:

• Before each registration– change in location areas– change in MSRN

• Before each call set up attempt– mobile originated– mobile terminated

• Before some supplementary services change– activation– deactivation




Mobility Management

SUBSCRIBER IDENTITY AUTHENTICATIONAND CIPHERKEY SETTING

A8 A3 A3K K

K

K

i i

c

c

RAND RAND

IMSI/TMSI

RAND

SRESSigned response

to the RAND

Ki = Individual Subscriber Authentication Key (128 bits)Kc = Cipher Key (64 bits)RAND = Random Number (128 bits)SRES = Signed Response (32 bits)A3 = Authentication AlgorithmA8 = Cipher Key Generating Algorithm

A8

Subscriber Identity Module

Rand #Generator

Mobile Station NetworkYes/No

=

SRES SRES




Mobility Management

AUTHENTICATION PROCESS

Network View

VLRs have the responsibility of managing the authentication process. In order for a VLR to authenticate amobile subscriber, it needs to obtain authentication information from the mobile subscriber’s home network.The VLR can be provided with either of the following information:

• the authentication key (Ki)

• a set of RAND/SRES/Kc vectors

If the VLR and HLR are in different Public Land Mobile Networks (PLMNs), then the HLR should onlyreturn sets of RAND/SRES/Kc.15

1 The VLR requests Authentication Parameters, consisting of a Random Number (RAND), SignedResponse (SRES), and the Cipher Key (Kc), from the mobile station’s HLR.16 The VLR can request upto 5 sets of parameters to be returned.

2 The Authentication Parameters are provided to the VLR.

3 The VLR/MSC initiates the authentication process by sending a message with the RAND to the BSS.

4 The BSS passes the message and RAND onto the MS. The MS runs the RAND and IndividualSubscriber Authentication Key (Ki) (stored on the SIM) through the A3 and A8 algorithms to get theSRES and Kc.

5 The MS sends the SRES back to the BSS.

6 And the BSS sends the SRES back to the VLR/MSC. If the SRES from the MS matches the SRES fromthe AUC, the MS passes authentication.

7 The Kc is provided to the BSS if ciphering of the data over the Air interface is to be provided.

A3 - Authentication Algorithm A8 - Cipher Key generating AlgorithmAUC - Authentication Center BSS - Base Station SystemHLR - Home Location Register IMSI - International Mobile Subscriber IdentityKc - Cipyer Key Ki - Individual Subscriber Authentication KeyPLMN - Public Land Mobile Network RAND - Random NumberSRES - Signed Response VLR - Visitor Location Register

15 . Reference: GSM 9.02, Version 3.8.0, Section 5.10.3, Page 300.16 . Reference: GSM 9.02, Version 3.8.0, Section 5.5.1, Page 216.




Mobility Management

AUTHENTICATION PROCESS

Network View

RAND,SRES,

KcIMSI

12

3

4

5

7

6

RAND

SRES

Kc

RANDSRES

RAND, SRES, KcRAND, SRES, KcRAND, SRES, KcRAND, SRES, KcRAND, SRES, Kc

VLR

OneRecord

Entry

HLR

A3 & A8Algorithms

SRES Kc

RAND

BSS

IMSI

AUC

RAND

Ki

Random #Generator

Home PLMN

Visited PLMN




Mobility Management

ENCRYPTED TRAFFIC CHANNEL INFORMATION




Mobility Management

ENCRYPTED TRAFFIC CHANNEL INFORMATION

3 1 26 1 3 8.25

TrainingSequence

0.577 ms Time Slot

Control Bits

HeadBits

TailBits

GuardBits

0 3 4 5 6 71 2 0 3 4 5 6 71 2 0 3 4 5 6 71 2


Type of Information Transmitted/Received bya Mobile Station every 26 Frames (120 msec)

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

Voice

Voice

Voice

Voice

Voice

Voice

Voice

Voice

Voice

Voice

Voice

Voice

Associated Signaling

Voice

Voice

Voice

Voice

Voice

Voice

Voice

Voice

Voice

Voice

Voice

Voice


Frame#

Frame#

Slot#

Slot#

TrafficInformation

TrafficInformation

Data Bits

57

Data Bits

57

114 data bits encrypted(per timeslot)

(using 13k BPS speech coders)




Mobility Management

DATA ENCRYPTION PROCESS

Exclusive OR Truth Table

IN 1 IN 2 OUT

0

0

0

0

0 0

1

1 1

1

11IN 1 OUTIN 2

The following figure shows the truth table for an exclusive or gate.




Mobility Management

DATA ENCRYPTION PROCESS

TDMAFrame #

(22 bit counter)

TDMAFrame #

(22 bit counter)

K KC CA5 A5

Transmitdata

Encrypted Dataover Air Interface

Receivedata

MOBILE STATION BASE STATION

0010110100101101

11001010

11100111 11100111cipherblock

cipherblock

Exclusive Or

A5

Kc

- Data encryption algorithm

- Encryption (Cipher) Key




Mobility Management

WHY VALIDATE MOBILE EQUIPMENT?

Since the subscriber identity is kept on the SIM which can be inserted in a variety of GSM phones,it is necessary to ensure that the phone being used on the network

1 . Has been approved to work on GSM systems. I.e., it doesn’t interfere with other usersconversations, etc.

2 . The equipment itself hasn’t been stolen or restricted from service for some other reason.

It would be a mistake to use your SIM card in a known-to-be-stolen piece of equipment, becausethe subscriber’s identity can be associated with the IMEI at the time of the call.

Version 1.0.0February 4, 1993 -- 17:08:15 [rjtimei.txt]



Mobility Management

WHY VALIDATE MOBILE EQUIPMENT?

.

.

.

......... .

. ... .. .. ... .. .. .. .. ... .. .. .. .. .. .. .. .. .. . .. .. .. .. . .. .. .. . .. .. . .. .. . .. . .. .. . .. . .. . .. . .. . .. . . .. . .. . .. . . .. . . .. . . .. . . .. . . . .. . . . .. . . . .. . . . . .. . . . . .. . . . . . . .. . . . . . . . . .. . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . .. . . . . . . . . . . .. . . . . . . . . .. . . . . . . . .. . . . . . . .. . . . . . . .. . . . . . .. . . . . . .. . . . . .. . . . . . .. . . . . .. . . . . . .. . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . .. . . . . . .. . . . .. . . . .. . . . .. . . .. . . .. . .. . . .. . .. . .. . .. .. . .. . .. .. . .. .. .. . .. .. .. .. .. .. .. .. .. ... .. .. ... .. ... .. ... ... ... ... ... ... ... ... .. ... .. ... .. .. .. .. .. .. .. .. .. .. .. . .. .. . .. .. . .. . .. . .. . .. . . .. . . .. . . .. . . . .. . . . . .. . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . .. . . . . .. . . . .. . . .. . . .. . .. . .. . . .. .. . .. . .. .. . .. . .. . .. . .. . .. . . .. . .. . . .. . . .. . . . .. . . . . .. . . . . .. . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . .. . . . . .. . . . . .. . . . .. . . .. . . .. . . .. . .. . .. . .. . .. . .. . .. .. . .. .. . .. .. .. .. .. . .. .. .. ... .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. . .. .. .. .. .. .. . .. .. .. .. . .. .. .. . .. .. .. . .. .. . .. .. . .. .. . .. .. . .. .. . .. . .. .. . .. . .. . .. . .. . .. .. . .. . .. . . .. . .. . .. . .. . .. . . .. . .. . .. . . .. . .. . . .. . . .. . .. . . .. . . .. . . .. . . .. . . .. . . .. . . .. . . . .. . . .. . . .. . . . .. . . .. . . . .. . . .. . . . .. . . . .. . . . .. . . . .. . . . .. . . . .. . . . .. . . . .. . . . . .. . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . . . .. . . . . .. . . . . . .. . . . . . .. . . . . . . .. . . . . . .. . . . . .. . . . . .. . . . . .. . . . .. . . . .. . . . .. . . . .. . . .. . . .. . . .. . . .. . . .. . . .. . .. . . .. . .. . .. . . .. . .. . .. . .. . .. . .. . .. .. . .. . .. . .. .. . .. .. . .. . .. .. .. . .. .. . .. .. .. .. . .. .. .. .. .. . .. .. .. .. .. .. .. .. .. . .. .. .. . .. .. . .. .. . .. . .. .. . .. . .. . . .. . .. . . .. . .. . . .. . . . .. . . . .. . . . .. . . . . .. . . . . . . .. . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . .. . . . . . . .. . . . . .. . . . .. . . . .. . . . .. . . .. . .. . . .. . . . .. . . . .. . . . .. . . . . .. . . . . . . .. . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . .. . . . . . .. . . . . .. . . . . .. . . . .. . . .. . . .. . . .. . .. . . .. . .. . .. . .. . .. .. . .. . .. .. .. . .. .. .. . .. .. .. .. .. .. .. .. .. ... .. .. .. ... .. ... ... .. ... ... ... ... ... .... ... .... .... ..... .... ...... ...... ........ ........... ..............................................................................

$39.99 ea

or bestoffer

$

.............. ... .. ... .. .. .. .. .. .. .. .. .. .. .. .. .. . .. .. . .. .. . .. . .. . .. . .. . .. . .. . . .. . .. . . .. . . . .. . . . .. . . . . .. . . . . . . . . . . . . . . . . . . . . . .. . . . . .. . . .. . . .. . .. . .. .. . .. .. .. .. .. .. .. ... ... ... ... .... .... ...... .... ... .. .. .. .. .. . .. . .. . . . .. . . . . . . . . . . . .. . . . .. . .. . .. .. .. .. .. ... .... ....... ..................................................................... ......... ...... ..... .... .... ... ... .. ... .. .. . .. .. . .. . .. . . . .. . . . . . . . . . . . . . . . . . .. . . .. . . .. . .. .. .. .. .. .. ... ... .... ...... ..... .... .... ... ... ... .. ... .. .. .. .. .. .. . .. .. . .. . .. . .. . .. . . . .. . . . .. . . . . . . . . .. . . . . . . . .. . . . . . . . . .. . . . .. . . .. . .. . .. .. . .. .. .. .. .. .. ... .. ... ... .... ..... ........ ............

............................... ...... ..... ... ... ... .. .. .. .. .. .. . .. . .. . .. . . .. . . . . .. . . . . . . . . . . . . . . .. . . . . . . .. . . . . . .. . . . .. . . . .. . . .. . . .. . .. . . .. . .. . .. . .. . .. . .. .. . .. .. . .. .. .. .. .. . .. .. .. ... .. . .. .. . .. . . .. . . . . . . . . . . . . . . . .. . . .. . .. . .. .. .. ... ... ... ..............................

.................................... ..... ... ... .. ... .. .. . .. .. . .. . . .. . . . .. . . . . . . . . . . . . .. . . . . . . .. . . . .. . . . .. . . .. . .. . . .. . .. . .. .. . .. .. . .. .. .. .. .. .. .. .. .. .. ... .. ... ... ... ... ... ... ... .. .. ... .. .. .. .. . .. .. . .. . .. . .. . .. . . .. . . . .. . . . . . . .. . . . . . . . . . . . . . .. . . . . . . .. . . . .. . . .. . . .. . .. . .. .. .. . .. .. .. .. ... .. ... ... ... ... ..... ..... ...............

................................ ..... ... .. .. .. .. . .. . . .. . . . . . . . . . . . . .. . . .. . .. .. .. .. ... ..... .......................... ...... ... ... ... .. .. .. . .. . .. . .. . . . . . .. . . . . . .. . . . . .. . . .. . .. .. . .. ... .. ... .... ...... ..... .... ... ... ... ... .. ... .. .. .. .. .. .. .. .. . .. .. . .. . .. . . .. . . .. . . .. . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . .. . . .. . . .. . .. . .. . .. .. . .. .. .. .. .. .. ... .. ... ... ... .... .... ...... ...... .... .... ... .. .. .. .. .. .. .. . .. . .. . . .. . . . . . .. . . . . . . . . . . .. . . . . .. . . .. . . .. .. . .. .. .. .. .. ... .. .... .. .... .. .... .. ... ... ... ... ... ... ... ... ... .... .

. .... .. .... .. ... ... ... ... ... ... ... ... ... ... ... .. .. . .. .. . . .. . . . . . . . . . . . . . . .. . . .. . .. .. .. .. .. .... .... .................................................................... .... ... ... .. .. .. .. .. .. . .. . .. . . . .. . . . . . . . . . . . . . . . . .. . . . .. . .. . . .. . . .. . .. . .. . .. . .. .. . .. .. . .. .. . .. .. .. .. .. .. .. .. .. .. .. .. ... .. .. ... ... .. ... ... ... ... .... ... ... .. .. .. .. .. . .. . .. . . . .. . . . . . . . . . . .. . . . .. . . .. . .. .. .. .. ... ... .... ................................................................................ ....... ..... ..... ... .... ... ... .. ... .. ... .. .. .. .. .. . .. . .. . .. . . . .. . . . . . . . . ... . . . . . . . . .. . . . .. . .. . .. . .. .. .. .. .. ... .. .... .... ....... ...................... ..... ... ... .. .. .. .. .. . .. . . .. . . . .. . . . . . . . .. . . . . .. . . .. .. . .. .. .. ... ... .... ........................................... .............................. ................... ................ ......... ........ ........ ...... ...... ..... ..... ..... ..... .... .... ..... ... .... .... ... .... ... .... ... ... .. .. .. .. .. .. .. . .. . . .. . . .. . . . . . . . . . . . . . . . . . . .. . . . .. . .. . .. . .. .. .. .. ... .. .... ... ...... .........................

......... ......... ..... .... ... .. ... .. .. .. .. .. .. . .. .. . .. . . .. . . . .. . . . . . . . . .. . . .. . . . . . . . . .. . . . .. . . .. . . .. . .. . . .. . .. . .. . .. . .. . .. . .. . .. .. . .. .. . .. .. . .. .. .. .. .. . .. .. .. .. .. .. ... .. .. .. .. ... .. .. ... ... .. .. .. .. .. .. .. . .. . .. . . .. . . .. . . . . . . . . . . . . . . . . . . . . . .. . . . .. . .. . .. . .. .. . .. .. ... .. .. ... .... .... ....... ............ ..........

......... ...............................................................................

........................................................ .......... ....... ...... ..... ..... .... .... .... ... ... .. ... ... .. .. ... .. .. .. .. .. .. .. . .. .. .. . .. .. . .. . .. . .. . . .. . .. . . .. . . . .. . . . . .. . . . .. . . . .. . . .. . . .. . . .. . . .. . .. . .. . . .. .. . .. . .. . .. .

. . .. .. .. . .. .. .. .. .. .. . ... .. .. .. .. .. ... .. .. ... .. .. .. . .. .. . .. . .. . .. . . .. . . . .. . . . . . . . . . . . . . . . . . . . . . .. . . . .. . . .. . .. . .. . .. .. . .. .. .. ... .. ... .. .. ... .. .. .. .. . .. .. .. . .. .. . .. . .. . .. . . .. . . .. . . . .. . . . . .. . . . . . . . . .. . . . . . . . . . . . . .. . . . . . . . . . . . . . . . .. . . . .. . . .. . .. . .. .. .. .. .. .. .. ... .... .... ......... .......................................................................................... ........... ........ .............. .......................................................................................................... .............. ...... ..... .... ... .... .. ... ... .. .. .. .. .. .. .. .. .. .. . .. .. . .. .. . .. . .. . .. . .. . . .. . . .. . . .. . . . .. . . . . .. . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . .. . . . . . . . . . . .. . . . . . . .. . . . . . . .. . . . . .. . . . . .. . . . .. . . . .. . . . .. . . . .. . . .. . . .. . . .. . .. . . .. . . .. . .. . .. . .. . .. . . .. . .. . . .. . . .. . . . . .. . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . .. . . . . .. . . .. . . .. . .. . .. . .. . .. . .. .. . .. .. . .. . .. . .. . .. . .. . .. . . .. . . .. . . . .. . . . .. . . . .. . . . . . .. . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . .. . . . . . .. . . . .. . . .. . .. . .. . .. . .. .. . .. .. .. .. .. ... .. ... ... ... ... .... ..... ...... ........ ............... ...................................................................................................................................................................................................... ............. ........ ....... ..... ..... .... ... ... ... .. ... .. .. .. .. .. .. .. .. . .. . .. . .. . .. . .. . . . .. . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . . . .. . . . . . . . . .. . . . . . . . .. . . . . . . . .. . . . . . . .. . . . . . . .. . . . . . .. . . . . . .. . . . . .. . . . . .. . . . . . .. . . . .. . . . .. . . . .. . .. . . .. . .. . .. . .. .. . .. .. . .. .. .. .. .. .. .. .. ... .. ... .. ... ... ... ... .... .... ..... ..... ..... .... .... .... .... .... .... ... ... .... ... ... ... ... ... ... ... .. ... ... .. ... .. ... .. ... .. .. ... .. .. .. .. .. .. . .. . .. . .. . . .. . . . .. . . . . . . . .. . . . . .. . . . . . . . .. . . . .. . . .. . .. . .. . .. .. .. .. .. .. ... .. ... ... .... ..... ... .. .. .. .. .. . .. . .. . . . .. . . . . . . . . . .. . . . .. . . .. .. . .. .. ... .. .... ...... ..................................................................... ......... ...... .... .... .... ... ... .. ... .. .. ... .. .. .. .. . .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ... .. .. .. ... .. ... .. ... .. ... ... .. ... ... ... ... ... ... .... ... .... .... .... ... .... ... ... ... ... .. ... .. .. ... .. .. .. .. .. .. . .. .. .. . .. .. . .. . .. . .. . .. . . .. . .. . . . .. . . . .. . . . .. . . . . . . . .. . . . . . . . . . . . .. . . . . . . . . . . . .. . . . . . . . . . . . . .. . . . . . . . . . . . .. . . . . . . . . . . . .. . . . . . . . . . . . . .. . . . . . . . . . . . .. . . . . . . . . . .. ... ............... ... .. .. ... .. .. .. .. .. .. .. .. .. .. .. .. . .. .. .. . .. . .. .. . .. . .. . .. . .. . . .. . .. . . .. . . .. . . . .. . . . . .. . . . . . . .. . . . . . . . . . . .. . . . . . . .. . . . .. . . .. . . .. . .. .. . .. .. .. . .. ... .. .. ... ... ... ... ..... ...... .... ... ... .. .. .. .. .. . .. . . .. . . . . . . . ... . . . . . . . .. . . .. . .. .. .. .. .. ... ... .... ............................

................................................... ....... ...... .... .... ... .... .. ... .. .. .. . .. .. . .. . . .. . . . . .. . . . . . . . . . . .. . . . . .. . . .. . .. . .. .. .. .. .. .. ... .... .... ....... .... .... .... ... ... .. ... .. .. .. .. .. .. .. . .. .. . .. . .. . . .. . .. . . . .. . . . . . .. . . . . . . . . . . . . . . . . . . . .. . . . . .. . . . .. . .. . .. . .. . .. .. .. .. .. .. .. ... ... ... ... .... ...... .................

.................................... ..... ... ... ... ... .. .. .. .. . .. . .. . .. . .. . . . .. . . . . . . . . . . . . . . . . . . . . . . .. . . . . . .. . . . .. . . . .. . . . .. . . .. . . .. . .. . . .. . .. . .. . .. .. . .. .. . .. .. . .. .. .. .. . .. .. .. .. ... . .. .. .. . . .. . . . .. . . . . . . . . . .. . . . .. . .. . .. .. .. .. .. ... ..... .............................

.................................. ..... .... ... .. .. .. .. .. .. . .. . .. . . .. . . . . . . . . . . . . . . . . . . . .. . . . . .. . . . .. . . . .. . .. . . .. . .. . .. . .. . .. .. . .. .. .. .. .. .. .. .. .. .. ... .. ... .. ... ... .... ... .. ... .. ... .. .. .. .. . .. .. .. . .. . .. . .. . . .. . . . .. . . . . .. . . . . . . . . . . . . . . . . . . . . . . .. . . . . .. . . . .. . .. . .. . .. . .. .. . .. .. .. .. .. ... .. ... ... ... .... ..... ....... .............

........................... ...... .... .. .. .. .. .. . .. . . . .. . . . . . . . .. . . . .. . .. .. .. .. .. .... ...... .......................... ..... ... .. ... .. .. . .. .. . .. . . . .. . . . . . . . . . . . . . .. . . .. . . .. .. . .. .. ... .. .... .... ...... ..... .... ... ... ... ... .. .. ... .. .. .. .. . .. .. . .. .. . .. . .. . . .. . . .. . . . .. . . . . . .. . . . . . . . . . . . . . . . . . . .. . . . . . .. . . . .. . . .. . . .. . .. .. . .. .. . .. .. .. .. .. .. ... ... .. ... .... .... ..... ....... ..... ... ... ... .. .. .. .. .. .. . .. . .. . .. . . . .. . . . . . . . . . . . . . . . . . . .. . . . .. . .. . .. . .. .. .. .. .. .. ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... .

.. ... ... ... ... ... ... ... ... ... ... ... ... ... ... .. .. .. . .. . .. . . . .. . . . . . . . . . .. . . .. . . .. .. .. .. .. ... .... ................................................................... ..... .... ... .. .. .. .. .. .. . .. . .. . .. . . . . . .. . . . . . . . . .. . . . . .. . . . .. . .. . . .. . .. . .. . .. . .. . .. . .. .. . .. .. .. . .. .. .. .. .. .. .. .. .. .. .. .. ... .. ... .. ... ... .. ... .... ... ... .... .. .. .. .. .. .. . .. . . .. . . . . . . . . . . . . . . . . .. . . .. . .. . .. .. .. .. ... ... ..... ......................................................................... ......... ...... ..... .... ... ... ... ... ... .. ... .. .. .. .. .. . .. .. . .. . . .. . . . . .. . . . . . . . . . . . . . .. . . . . .. . . .. . .. .. . .. .. .. .. .. ... ... .... ..... ............................. .... ... .. .. .. .. .. .. . . .. . . .. . . . . . . . . . . . . . . .. . . .. . .. . .. .. .. ... .. .... ..... .......................................................... ....................... ................ ............. .......... ........ ...... ....... ...... ..... ..... ..... .... ..... .... .... .... ... .... ... .... ... ... ... .. .. .. .. .. .. . .. . .. . . .. . . . . .. . . . . . . . . . . . .. . . . . .. . . .. . .. .. . .. .. .. .. ... ... ... ..... ...........................

................ ...... .... ... ... ... .. .. .. .. .. .. .. . .. . .. . .. . . .. . . . . .. . . . . . . . . . . . . . . . .. . . . . .. . . . .. . . .. . .. . . .. . .. . . .. . .. . .. .. . .. . .. . .. .. . .. .. . .. .. .. .. . .. .. .. .. .. .. .. .. .. .. ... .. .. .. ... .. ... .. ... .. .. .. .. .. .. . .. . .. . .. . . .. . . . . .. . . . . . . . . . . . . . . .. . . . . .. . . .. . .. . .. .. . .. .. .. ... .. ... ... .... ..... .......... .............. ..

...........................................................................................

.............................................. ............. ........ ...... ...... ..... .... .... .... ... ... ... ... .. ... .. ... .. .. .. .. .. .. .. .. . .. .. .. . .. . .. . .. . .. . .. . .. . . .. . . . .. . . . .. . . . .. . . . . .. . . .. . . .. . . .. . . .. . . .. . .. . .. . .. . .. . .. .. . .. .. . .. .. . .

. .. .. .. .. .. .. .. .. .. .. .. .. .. ... .. .. ... .. .. . .. .. .. . .. . .. . . .. . . .. . . . . . .. . . . . . . . . . . . . . .. . . . . . .. . . .. . . .. . .. . .. .. .. . .. .. ... .. .. ... .. .. ... .. .. .. . .. .. .. .. . .. . .. . .. . .. . .. . . .. . . .. . . . . .. . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . .. . . .. .. . .. .. .. .. .. .. ... ... .... ..... .................................................................................................... ........... ........ ............................................................................................................................. ........ ..... .... .... ... ... ... .. ... .. .. .. ... . .. .. .. .. .. . .. .. . .. . .. .. . .. . . .. . .. . . .. . . .. . . .. . . . . .. . . . . .. . . . . . . . . . .. . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . .. . . . . . . . . .. . . . . . . .. . . . . . .. . . . . .. . . . .. . . . .. . . . .. . . . .. . . .. . . .. . . .. . . .. . .. . . .. . .. . . .. . .. . .. . .. . .. . . .. . . .. . . . .. . . . . .. . . . . . . . . . .. . . . . . . . . . . .. . . . . . . . . . .. . . . . .. . . . .. . . .. . . .. . .. . .. . .. .. . .. .. . .. . .. .. . .. . .. . .. . . .. . .. . . .. . . .. . . . .. . . . .. . . . . . .. . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . .. . . . . . . . . .. . . . . .. . . .. . . .. . .. . .. .. . .. .. . .. .. .. .. ... .. .. ... ... ... .... .... ..... ........ ............. ................................................................................................................................................................................................................... ......... ........ ...... ..... .... .... ... ... .. ... .. ... .. .. .. . .. .. .. . .. . .. . .. . .. . . .. . . . .. . . . . .. . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . .. . . . . . . . . .. . . . . . . .. . . . . . . . .. . . . . . .. . . . . . . .. . . . . . .. . . . . .. . . . . .. . . . . . .. . . . .. . . . . .. . . .. . . .. . . .. . .. . .. . .. . .. . .. .. .. . .. .. .. .. .. .. .. ... .. .. ... ... .. ... .... ... .... .... ...... .... ..... .... .... .... .... .... ... .... ... ... .... ... ... ... .. ... ... ... .. ... ... .. ... .. ... .. .. ... .. .. .. .. .. .. . .. .. . .. . . .. . . .. . . . . .. . . . . . . . . . . . . . . . . .. . . . . .. . . .. . . .. . .. .. . .. .. .. .. .. .. ... ... ... ... ..... ... ... .. .. .. .. .. . .. . . .. . . . . . . . . . . . . . . . .. . . .. . .. . .. .. .. ... ... .... .............................................................................. ....... ..... .... .... ... ... ... ... .. .. ... .. .. .. .. . .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ... .. .. ... .. .. ... .. ... ... .. ... ... ... ... ... ... ... ... .... ... .... .... ... .... ... .... .. ... ... .. ... .. .. ... .. .. .. .. .. . .. .. .. . .. .. . .. .. . .. . . .. . .. . .. . . .. . . . .. . . . .. . . . . . .. . . . . . . . . . .. . . . . . . . . . . . .. . . . . . . . . . . . . .. . . . . . . . . . . . .. . . . . . . . . . . . . .. . . . . . . . . . . . .. . . . . . . . . . . . . .. . . . . . . . . . . . .. . . . ... .. .

.....................................................................................................................

............................................................... ...... ..... ... .... ... .. ... .. .. ... .. .. ... .. .. ... .. ... .. ... .. ... ... .. ... ... ... .. ... ... ... ... ... ... ... ... ... .... ... ... .... .... .... .... ..... ..... ..... ..... ....... ..

..... ......... ........... .......................... .........................................

.....................................................................................................

............ ............ ..... ..... ... .... .. ... .. ... .. ... .. .. .. ... .. .. .. .. .. .. .. .. .. .. .. .. .. .. . .. .. .. .. . .. .. . .. .. . .. .. . .. . .. .. . .. . .. . .. . .. . .. . . .. . .. . . .. . . .. . . .. . . .. . . .. . . .. . . . .. . . . .. . . . .. . . . .

. . . . .. . . . . .. . . . . . .. . . . . . .. . . . . . .. . . . . . . . .. . . . . . . . . .. . . . . . . . . . . . .. . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . .. . . . .. . . .. . .. . .. . .. . .. .. . .. .. .. .. ... .. .. ... ... ... .... .... ...... ..................................................................................... .......... ........ ...... ..... ..... .... .... .... ... ... .... ... ... ... .. ... ... .... ... ..... ...... .......... .................................................................................................................................................... ....... ..... ... ... ... ... .. .. .. .. .. .. .. . .. .. . . .. . .. . . .. . . . . .. . . . . . .. . . . . .. . . .. . . .. . .. . .. . .. . .. . .. .. . .. .. .. . .. .. .. .. ... .. .. ... .. ... ... ... ... ... .... ..... ..... ........ ........................................................................... ............. ......... ....... ....... ...... ..... ..... ..... ..... ..... ..... .... ..... ... .... .... ... ... ... .... .. ... ... ... .. ... .. ... .. .. ... .. .. .. .. .. .. ... . .. .. .. .. .. .. .. . .. .. .. . .. .. .. . .. .. .. . .. .. .. . .. .. .. . .. .. .. . .. .. .. . .. .. .. . .. .. .. . .. .. .. . .. .. .. . .. .. .. . .. .. .. . .. .. .. . .. .. .. . .. .. .. .....................

haveSIM

will travel

SIM




Mobility Management

EQUIPMENT VALIDATION PROCESS

1 The MSC requests the IMEI from the MS.

2 The MS provides the IMEI.

3 The MSC sends a MAP query to the EIR requesting the status of the IMEI

4 The EIR returns one of four possible responses.

1 . Not on the approved MS type list. - This equipment has not been included in the rangesof equipment which are approved for this network.

2 . On the approved MS type list. - This equipment is included in the ranges of equipmentwhich are approved for this network.

3 . On the approved MS type list, but listed as monitor this particular MS. - This equipmenthas been approved, but provide special call records or alert the service provider this MSis in use.

4 . On the approved MS type list, but service to this MS is restricted. - This equipment iswithin the range of approved equipment, but this MS should not be provided service(stolen, etc.).

EIR - Equipment Identity RegisterMS - Mobile StationMSC - Mobile Switching CenterIMEI - International Mobile Station Equipment Identity




Mobility Management

EQUIPMENT VALIDATION PROCESS

MSC

EIR

MS

1

3

2

4

CHECKIMEI

Request IMEI

IMEICHECK

Response

IMEI




Mobility Management




Detailed LocationRegistration Scenario




Mobility Management

PHASES OF A MOBILE STATION

LOCATION REGISTRATION UPDATE

Version 1.0.0July 3, 1991 -- 13:48:41 [djw0680.txt]



Mobility Management

PHASES OF A MOBILE STATION

LOCATION REGISTRATION UPDATE

• Request for Service

• Authentication∗

• Update Location Registers∗

• Ciphering∗

• TMSI Reallocation∗

∗ Phase might not occur




Mobility Management

MOBILE LOCATION UPDATE

Request for Service

In the following location update scenario, it is assumed that a mobile station enters a new location area that is undercontrol of a different VLR (referred to as the "new VLR") than the one the mobile station is currently registered (referredto as the "old VLR").

0 The mobile station enters a new cell area, listens to the Location Area Identity (LAI) being transmitted on thebroadcast channel, and compares this LAI with the LAI stored in the SIM, which represents the area where themobile subscriber was last officially registered.

1 The mobile station determines that it has entered a new Location Area and transmits a Channel Request messageover a common access channel, Random Access Channel (RACH). The access scheme for this channel is similar inconcept to slotted ALOHA. Although unlikely, it is possible that the mobile will have to retry this message severaltimes.

2 Once the base station receives the Channel Request message, it allocates a Stand-alone Dedicated Control Channel(SDCCH) and forwards this channel assignment information to the mobile station over the Access Grant Channel(AGCH). It is over the SDCCH that the mobile station will communicate with the BSS and MSC.

3 The mobile station transmits a location update request message to the base station over the SDCCH. Included inthis message is the mobile station Temporary Mobile Subscriber Identity (TMSI) and Location Area Identification(LAI). This message also establishes a layer 2 signaling connection between the mobile station and the base station.

4 The base station forwards the location update request message to the MSC. This message also causes the startup ofa SCCP connection.

5 The MSC informs its VLR of the location update request. The mobile station can identify itself either with its IMSIor TMSI. In this example we’ll assume that the mobile provided a TMSI. Also included in this message is the LAIof the last area the mobile station was registered.

6 The VLR analyzes the LAI supplied in the message and determines that the TMSI received is associated with adifferent VLR (old VLR). In order to proceed with the registration, the IMSI of the mobile station must bedetermined. The new VLR has two options:

• Derive the identity of the old VLR from the LAI, supplied in the location update request message, and requestthe old VLR to supply the IMSI for a particular TMSI. First Choice!

• Request the mobile station supply its IMSI. Second Choice, want to avoid transmitting the IMSI across the Airinterface as much as possible.

In this example, we’ll assume that the networking capability between VLRs doesn’t exist and that the new VLR isonly left with the option of requesting the mobile station to supply its IMSI. The VLR sends to the MSC a requestfor the mobile station’s IMSI.

7 The MSC forwards the VLR’s IMSI request to the mobile station. Note that this message is sent transparentlythrough the BSS. This message is also used to complete the establishment of the SCCP connection between theBSS and the MSC.

8 The mobile station reads its IMSI and transmits it to the BSS over the SDCCH. The BSS transparently transfers thismessage to the MSC.

9 The MSC forwards the IMSI response to the new VLR.




Mobility Management


Request for Service

9

2

IMSI Acknowledge

IMSI Acknowledge

Request IMSI

Request IMSI

Location UpdateRequest

...................................................................................................................

...................................................................................................................

NewVLR

MSCBSSMS

...............................................................................................................

.................................................................................................................

Dedicated SignalingChannel Assigmnent

Channel Request1



B AUm

3

4

5

6

7

8




Mobility Management


Authentication

Since the air interface is vulnerable to fraudulent access, it is necessary to determine if theInternational Mobile Station Identity (IMSI) received from the mobile station is from theSubscriber Identity Module (SIM) that was assigned this IMSI.

Authentication is built around the notion that an Authentication Key (Ki) resides in only twoplaces: in an Authentication Center (AUC) and in the user’s SIM. Since the authentication key, Ki,is (or should) never transmitted, it is virtually impossible for unauthorized individuals to obtain thiskey to impersonate a give mobile subscriber.

10 If authentication is to be performed on the mobile station, it is possible that the "new VLR"will not have any "authentication triplets" (RAND, SRES, and Kc) available for theregistering IMSI. Since we assumed that we were unable to communicate with the old VLR onthe previous page, lets assume that we have to request authentication triplets from the AUC.The GSM standard allows a VLR to request in advance up to 5 "authentication parameters"from the Authentication Center (AUC), via the HLR. In this scenario, the new VLR sends arequest to the HLR requesting authentication parameters for the specified IMSI.

11 The HLR forwards this request to the authentication center.

12 The AUC, using the IMSI, extracts the subscriber’s authentication key (Ki). The AUC thengenerates a random number (RAND), applies the Ki and RAND to both the authenticationalgorithm (A3) and the cipher key generation algorithm (A8) to produce an authenticationSigned Response (SRES) and a Cipher Key (Kc). The AUC then returns to the HLR therequested number (i.e., one to five copies) of authentication parameters: RAND, SRES, andKc. Each time the AUC produces a set of authentication parameters, the values will bedifferent.

13 The HLR forwards the requested number of authentication parameters to the VLR.

14 The VLR then sends a message to the MSC requesting that the mobile station beauthenticated. Included in the message is a random number (RAND).

15 The MSC forwards the authentication request message to the mobile station. The mobilestation reads its authentication key (Ki) from the SIM, applies the random number (RAND)and Ki to both its Authentication Algorithm (A3) and Cipher key generation Algorithm (A8)to produce an authentication Signed Response (SRES) and Cipher Key (Kc). The mobilestation saves Kc for later, and will use Kc when it receives command to cipher the channel.

16 The mobile station returns the generated SRES to the MSC.

17 The MSC forwards SRES to the VLR. The VLR compares the SRES returned from themobile station with the expected SRES receive earlier from the AUC. If equal, the mobilepasses authentication. If unequal, appropriate actions will be taken--which could result in theSIM being disabled. In this scenario, we’ll assume that authentication passes.




Mobility Management


Authentication

17

16

15

14

13

12

11

10

.........................................................................................................

.........................................................................................................

.........................................................................................................

.......................................................................................................

.......................................................................................................

AuthenticationParameters

AuthenticationResponse


AuthenticateMobile Station



MSD

HLR AUCNEWVLR

B

MSC

GetAuthentication

Parameters

GetAuthentication

Parameters




Mobility Management


Update Location

At this point, we are ready to request the subscriber data from the HLR, inform the HLR that themobile station is under control of a new VLR and that the mobile station can be deleted from theold VLR.

18a The VLR requests the subscriber data from the HLR to build the VLR record for this MS.

18b The HLR sends the VLR the subscriber data in an Insert Subscriber Data message. The VLRbuilds the VLR record.

18c The VLR sends an Insert Subscriber Data Result message to the HLR to confirm that the VLRrecord has been built correctly.

19 The HLR marks the HLR record for that subscriber with the new VLR address and confirmsthat the MS is now considered to be registered in the new VLR.

20 If the mobile station is also registered in an old VLR, the HLR will send a message to the oldVLR informing it that the VLR entry for the specified IMSI can be deleted.

21 The old VLR deletes the subscriber record and sends an acknowledgement of deletion to theHLR.




Mobility Management


Update Location

20

DeleteMobile Station

D D

Insert Subsc.Data Result

InsertSubscriber Data

Location Updated

Update Location

OldVLR

HLRNewVLR

...............................................................................................

...............................................................................................

...............................................................................................

Mobile StationDeleted

21

19

18c

18b

18a




Mobility Management


Ciphering

At this point in time, the HLR and "old VLR" have been informed that the mobile station hasregistered with a MSC under the control of the "new VLR."

The remaining task for the new VLR is to allocate and transmit a new TMSI to the mobile station.For security reasons, the radio channel is encrypted before sending the new TMSI to the mobilestation.

22 The VLR requests the MSC to cipher the radio channel. Included in this message is theCipher Key (Kc), which was made available eariler during authentication.

23 The MSC forwards this request to the BSS.

24 The BSS retrieves the cipher key, Kc, from the message and then transmits a request to themobile station requesting it to begin ciphering the channel.

25 The mobile station uses the cipher key generated previously when it was authenticated tocipher the uplink channel, and transmits a confirmation over the ciphered channel to the BSS.

26 The BSS upon receiving the cipher mode complete message uses the cipher key it previouslyreceived from the MSC to cipher the downlink channel. The BSS then sends a ciphercomplete message to the MSC.




Mobility Management


Ciphering

26

Encipher Complete

Cipher ModeComplete

Cipher ModeCommand

Encipher Command

Set Ciphering

NewVLR

MSCBSSMS

.................................................................

...................................................................

B AUm

22

24

23

...................................................................

...................................................................

25




Mobility Management


TMSI Reallocation

27 The VLR informs that MSC that the mobile location update sequence is complete. The VLRforwards in this message the new TMSI for the mobile station.

28 The MSC forwards the location update complete message to the mobile station.

29 The mobile station retrieves the new TMSI value from the message and updates its SIM withthis new value. The mobile then an update complete message back to the MSC.

30 The MSC requests the BSS to tear down the SCCP signaling connection be released betweenthe MSC and the mobile station.

31 The BSS sends a "radio resource" channel release message to the mobile station and then freesup the Stand-alone Dedicated Control Channel (SDCCH) what was allocated previously. TheBSS then informs the MSC that the signaling connections has been cleared.

32 The MSC releases its portion of the SCCP signaling connection.




Mobility Management


TMSI Reallocation

32

...............................................................................

..............................................................................

Location UpdateAccept

Location UpdateAccept

Um A B

MS BSS MSC NewVLR

Location UpdateComplete

Clear SignalingConnection

Release RadioSignaling Channel

Clear Complete

...............................................................................

...............................................................................

27

28

29

30

31




Mobility Management




Unit 4

Call Management

Version 1.0March 2, 1993 -- 13:18:47 [unit04]



Call Management

UNIT OVERVIEW

Version 1.0June 28, 1991 -- 11:08:43 [djw0459.txt]



Call Management

UNIT OVERVIEW

Mobile to Land Call Scenario

Mobile to Mobile Call Scenario

Land to Mobile Call Scenario

Handover Overview

Handover Scenarios

Version 1.0May 16, 1991 -- 16:20:43 [djw0459.pic]



Call Management

GSM REFERENCE MODEL




Call Management

GSM REFERENCE MODEL

Abis

EIR

ISDN

PSTN

MSC

MSC

HLR



AUC

VLR

VLR

BSC

BTS

BSS

MS

F

E

C

A

B

G

D

Um

Version 1.0November 27, 1991 -- 14:17:56 [djw0410.pic]



Call Management

REQUIRED FACILITIES FOR A MOBILE-LAND CALL




Call Management

REQUIRED FACILITIES FOR A MOBILE-LAND CALL

Fixed Public Land NetworkPublic Land Mobile Network .................................

Mobile Station

BSS MSC

Fixed Station

LinePSTN

4. Line (PSTN - Fixed Station)

- Base Station System- Mobile Switching Center- Public Switched Telephone Network

BSSMSCPSTN

1. Radio Channel (Mobile Station - BSS)2. Voice Trunk (BSS - MSC)

3. Voice Trunk (MSC - PSTN)

VoiceTrunk

VoiceTrunk

RadioChannel

Version 1.0July 30, 1991 -- 12:27:46 [djw0212.pic]



Call Management




Mobile to LandCall Scenario




Call Management

PHASES OF A MOBILE TO LAND CALL

The following table provides references to GSM and CCITT recommendations that pertain to amobile originated call:

_ _________________________________________________________________Recommendation Title_ _________________________________________________________________

GSM 04.08 Mobile Radio Interface Layer 3 SpecificationGSM 08.08 Base Station to Switch Interface, Layer 3 SpecificationCCITT Q.721-Q.725 Telephone User PartCCITT Q.761-Q.764 ISDN User Part_ _________________________________________________________________

Version 1.0November 20, 1991 -- 15:19:26 [djw0672.txt]



Call Management




• Ciphering∗

• Equipment Validation∗

• Call Setup

• Handover(s)∗

• Release


Version 1.0June 28, 1991 -- 11:52:39 [djw0672.pic]



Call Management

MOBILE TO LAND CALL

Request for Service

The following is an example of an interprocessor message scenario for a mobile-to-land call. It isassumed that the mobile station is already registered with the system and has been allocated aTemporary Mobile Identification Number (TMSI).

0 A mobile originated call starts by the user entering the directory number digits, associatedwith the person to be called, on the mobile station handset. The user presses the "send" keyafter all digits have been entered.

1 Mobile station transmits a channel request message over a common access channel, RandomAccess Channel (RACH). The access scheme for this channel is similar in concept to slottedALOHA. Although unlikely, it is possible that the mobile will have to retry this messageseveral times.

2 Once the base station receives the Channel Request message, it allocates a Stand-aloneDedicated Control Channel (SDCCH) and forwards this channel assignment information tothe mobile station over the Access Grant Channel (AGCH). It is over the SDCCH that themobile station will communicate with the BSS and MSC until a traffic channel is assigned.

3 The mobile station transmits a service request message to the base station over the SDCCH.Included in this message is the mobile station TMSI and Location Area Identification (LAI).This message also establishes a layer 2 signaling connection between the mobile station andthe base station.

4 The base station forwards the service request message to the MSC. This message also causesthe startup of a SCCP connection, if the mobile station does not have any other call instancesactive.

5 The MSC informs its VLR that a particular mobile station is requesting service.

Version 1.0July 12, 1991 -- 15:37:50 [djw0634.txt]



Call Management

MOBILE TO LAND CALL

Request for Service

5

4

3

Service Request

Service Request

Service Request

Dedicated SignalingChannel Assignment

.........................................................................

.......................................................................

MS BSS MSC VLR

Channel Request

.........................................................................

.........................................................................

1

Um A B

2




Call Management

MOBILE TO LAND CALL

Authentication

Since the air interface is vulnerable to fraudulent access, it is necessary to determine if the TMSIreceived from the mobile station is from the SIM that was assigned this TMSI.

Authentication is built around the notion that an Authentication Key (Ki) resides in only twoplaces: in an Authentication Center (AUC) and in the user’s SIM card. Since the authenticationkey is (or should) never be transmitted, it is virtually impossible for unauthorized individuals toobtain this key to impersonate a give mobile subscriber.

6 Three authentication parameters (also referred to as "authentication triplets") are required bythe VLR in order to authenticate a given mobile station: an authentication random number, anauthentication signed response, and a cipher key (RAND, SRES, and Kc). The VLR iscapable of requesting and storing up to five authentication triplets (per registered subscriber)from the AUC, via the mobile subscriber’s HLR.

In this scenario, we’ll assume that the VLR does not have any authentication triplets availablefor the TMSI requesting service. Since the mobile station is registered with the VLR, theVLR is capable of translating the mobile station’s TMSI into its IMSI. The VLR transmits arequest to the mobile station’s HLR requesting more authentication parameters. Included inthe message is the IMSI of the mobile station.


8 The AUC, using the IMSI, extracts the subscriber’s authentication key (Ki). The AUC thengenerates a random number (RAND), applies the Ki and RAND to both the authenticationalgorithm (A3) and the cipher key generation algorithm (A8) to produce an authenticationSigned Response (SRES) and a Cipher Key (Kc). The AUC then returns to the HLR anauthentication triplet: RAND, SRES, and Kc.

9 The HLR forwards the authentication triplets to the VLR.


11 The MSC forwards the authentication request message to the mobile station. The mobilestation reads its authentication key (Ki) from the SIM, applies the random number (RAND)and Ki to both its authentication algorithm (A3) and cipher key generation algorithm (A8) toproduce an authentication Signed Response (SRES) and Cipher Key (Kc). The mobile stationsaves Kc for later, and will use Kc when it receives command to cipher the channel.



Version 1.0April 15, 1992 -- 18:24:13 [djw0635.txt]



Call Management

MOBILE TO LAND CALL

Authentication

13

GetAuthentication

Parameters

GetAuthentication

Parameters

MSC

B

VLR AUCHLRD

MS







.......................................................................................................

.......................................................................................................

.........................................................................................................

.........................................................................................................

.........................................................................................................

6

7

8

9

10

11

12




Casa

Nota adhesiva

SDCCH 6 - 9, La autenticación es opcional

Casa

Nota adhesiva

El móvil usa el número random que se le envía y lo mezcla con el Ki, usa los algoritmos, obtiene un SRES y el Kc. Envía el SRES hacia la VLR el sistema compara, si el SRES que tiene con el SRES que el móvil envío, si la respuesta es si autentico y pasa, sino lo es no pasa.

Casa

Nota adhesiva

Le es enviado el RAND generado por el sistema al móvil.

Casa

Nota adhesiva

Le pasa el IMSI

Casa

Nota adhesiva

La autenticación es opcional, depende de que el operador lo tenga mapeado, configurado, pero se puede sugerir hacerlo cada vez que hace location update, se ahorra mensajería y mejoraría el tiempo de acceso, el canal que se usa para hacer ese proceso es el SDCCH, el tiempo de uso del SDCCH es menor, el SDCCH consume menos tiempo y me voy a poder comunicar más rápido. Disminuye el Holding time, el periodo de retención.

Call Management

MOBILE TO LAND CALL

Ciphering









Call Management

MOBILE TO LAND CALL

Ciphering

18

17

...................................................................

...................................................................

15

16

14

Um A B

...................................................................

.................................................................

MS BSS MSC VLR

Set Ciphering

Encipher Command

Cipher ModeCommand

Cipher ModeComplete

Encipher Complete




Casa

Nota adhesiva

El sistema manda la clave de cifrado (Kc), después de la autenticación ahora vamos a cifrar.

Casa

Nota adhesiva

El cifrado se produce entre el móvil y la estación base.

Call Management

MOBILE TO LAND CALL

Equipment Validation

At this point in time, the mobile station has been authenticated and the radio channel is beingencrypted.

Two events will now occur in parallel:

• The MSC interrogates the mobile station for its equipment number and checks the equipmentagainst information in the Equipment Identity Register (EIR).

• The mobile station, after receiving the cipher command, forwards a call setup request to theMSC.

For ease of discussion in this scenario, the equipment validation phase is shown to occur before themobile forwards the the call setup request message.

19 The MSC transmits a request to the mobile station requesting it to respond with itsInternational Mobile Equipment Identity (IMEI).

20 The mobile station upon receiving this request, reads its equipment serial number and returnsthis value to the MSC.

21 The MSC then requests the EIR to check the IMEI for validity. The EIR will first check to seeif the IMEI value is within a valid range. If so, it then check so see if the IMEI is on a suspector known list of invalid equipment.

22 The EIR returns to the MSC the results of the IMEI validation. If the results are negative, theMSC might abort the call or possibly let the call continue but inform the network serviceprovider of the event. In this scenario, we’ll assume that the IMEI is valid.

It would not be to wise of a mobile subscriber with a valid SIM card registered in their name tosteal mobile equipment. If such a subscriber was to initiate a call on a piece stolen equipment, thatwas reported as stolen in the EIR, the mobile station would pass authentication and fail equipmentvalidation. Since the system knows the IMSI of the individual using the stolen equipment, thesystem could report to the network provider the identification of the SIM owner.




Call Management

MOBILE TO LAND CALL


IMEI Request

EIRMSC MS

...................................................................

19

21

20

...................................................................

...................................................................

IMEI Response

Check IMEI

IMEI CheckResults22

F




Casa

Nota adhesiva

Verifica si el equipo es robado.

Call Management

MOBILE TO LAND CALL

Call Setup -- with Mobile

23 The mobile station transmits a call setup request to the MSC after it begins ciphering the radiochannel. Included in this request message are the dialed digits.

24 The MSC, upon receiving the call setup request message, will request the VLR to supplysubscriber parameters necessary for handling the call. The message will contain the callednumber and service indication, if required and available.

25 The VLR will check for call barring conditions, such as the mobile station being barred frommaking specific outgoing calls (e.g., international calls), or possibly if some supplementaryservices are active which prevent the call from being granted. If the VLR determines that thecall can not be processed, the VLR will provide the reason to the MSC. In this scenario, we’llassume that this procedure is successful. The VLR returns a message to the MSC containingthe service parameters for the particular subscriber.

26 The MSC informs the mobile station that the call is proceeding.

27 The next four steps involve establishing voice path resources between the MSC and themobile station. The MSC allocates an available trunk to the BSS currently serving the mobilestation. The MSC sends a message to the BSS supplying it with the trunk number allocated,and requests the BSS to allocate a radio traffic channel for the mobile station.

28 The BSS allocates a radio traffic channel and transmits this assignment to the mobile stationover the Stand-alone Dedicated Control Channel (SDCCH).

29 The mobile station tunes to the assigned radio traffic channel and transmits anacknowledgment to the BSS.

30 The BSS connects the radio traffic channel to the assigned trunk to the MSC. Since a smallportion of a radio traffic channel is available for out-of-band signaling, the SDCCH is nolonger used for signaling between the BSS and mobile station. The BSS deallocates theSDCCH. The BSS then transmits a trunk and radio assignment complete message to theMSC.




Call Management

MOBILE TO LAND CALL


30

26

......................................................................................................

......................................................................................................

24

25

23

Um A B

......................................................................................................

....................................................................................................

MS BSS MSC VLR

Call Setup Request

Call Proceeding

Assign RadioChannel

Radio AssignmentComplete

Trunk & RadioAssignmentComplete

Subscriber Data

Access SubscriberData

Assign Trunk &Radio

27

28

29




Casa

Nota adhesiva

Pedido de un canal de comunicación, hemos accesado con los canales RACH y con el AGCH hemos devuelto el SDCHH, el SDCCH primero se usa para autenticar, luego para pasar la clave de cifrado, después para verificar el IMEI, luego se establece la comunicación.

Casa

Nota adhesiva

Call Setup - Establecimiento de la comunicación.

Casa

Nota adhesiva

El profile del abonado esta en la VLR, pues el abonado podría estar restringido para las llamadas internacionales, la VLR tiene una copia de registro del abonado, por eso el MSC consulta a la VLR

Casa

Nota adhesiva

El MSC asigna una troncal entre el MS y la BSS, BTS y BSS.

Casa

Nota adhesiva

Ahí muere el uso del SDCCH

Casa

Nota adhesiva

Usa el FACCH trabaja con el canal de radio, por qué es FACCH y no TCH? FACCH se define como el mismo TCH pero con Stealing Flags setteados, es el mismo TCH cuando se usa para señalazación se settean los Stealing Flags y se convierte en FACCH. Dentro del bus hay 2 bits Stealing Flags, por que se cambían pues no está pasando la voz entonces los canales de voz TCH se reutilizan para la señalazación utilizando los Stealing Flags.

Call Management

MOBILE TO LAND CALL

Call Setup -- with Land Network

At this point in time a voice-path has been established between the mobile station and the MSC.The mobile station user hears silence since the complete voice path has not be yet established. Thelast phase of setting up a mobile-originated call involves the MSC establishing a voice path fromthe MSC to the Public Switched Telephone Network (PSTN).

31 The MSC sends a network setup message to the PSTN requesting that a call be setup.Included in the message are the mobile station’s dialed digits and details specifying whichtrunk should be used for the call.

32 The PSTN may involve several switching exchanges before finally reaching the final localexchange responsible for establishing applying ring to the destination phone. The localexchange will play audible (ringing tone) over the trunk, or series of trunks (if severalintermediate switching exchanges are involved), to the MSC. At this point in time, the mobilestation use will hear ringing tone. The PSTN notifies the MSC with a network alertingmessage when this event occurs.

33 The MSC informs the mobile station that the destination number is being alerted. Note, this isprimarily a status message to the mobile station. The mobile station user will hear a ringingtone from the destination local exchange through the established voice path.

34 When the destination party goes off-hook, the PSTN will inform the MSC of this event. Thisevent usually triggers the beginning of billing. At this point, the mobile station user will beconnected to the desired destination party.

35 The MSC informs the mobile station that connection has been established.

36 The mobile station acknowledges the receipt of the connect message.

Note: the type of signaling used between the MSC and the PSTN is not defined and within thescope the GSM recommendations. In general, the MSC interface with the PSTN must conform tothe signaling conventions used within a given country. The message titles network setup, networkalerting, and connect on the following page are generic terms. For a MSC-PSTN interface basedon Signaling System number 7 (SS7), the network setup message would be an Initial AssignmentMessage (IAM).

Version 1.0November 20, 1991 -- 14:43:52 [djw0639.txt]



Call Management

MOBILE TO LAND CALL


36

34

..............................................................................

..............................................................................

32

33

31

..............................................................................

MS MSC PSTN

Network Setup

Network Alerting

Alerting

Connect (answer)

Connect

ConnectAcknowledgment

35




Casa

Nota adhesiva

E1's, Señalización SS7 tipo ISUP, lo primero que se hace es tomar una troncal, término en inglés de tomar troncal: seizure, mensaje ISUP para tomar la troncal y para mandar información al mismo tiempo IAM (Initial Address Message).

Casa

Nota adhesiva

El PSTN verifica que el abonado está libre y envía un ACM (Address Complete Message). Dentro del ACM hay un campo que indica que el abonado B está libre. Si B está libre

Casa

Nota adhesiva

IAM tiene: el # al que voy a llamar (called number) #B y también quién esta llamando (cally number) #A Hago una toma, reserva del canal también tiene la categoria del abonado, si es normal, o si tiene prioridades. Abonado normal, Abonado prioritario, prioridad cuando? Teléfonos móviles del capitán de los bomberos, el Presidente, Ministros. Hay esquemas de manejos de emergencia, en los cuales la red PSTN apropiadamente configurada, cuando hay un terremoto, atentado el sistema detecta abonados prioritarios y libera recursos de la red y se lo da a esos abonados, esos abonados tienen prioridad sobre el resto.

Casa

Nota adhesiva

PSTN envía la señal que llega al teléfono se llama corriente de timbrado (Rinning Current) voltaje rms de está corriente 75 Vrms, frecuencia 25 Hz, al mismo tiempo. La PSTN envía hacia atrás envía el tono (audio tinnn rinn) de llamada o rellamada (RBT Ring Back Tone), frecuencia de 425 Hz. El tono sale desde la última central donde está conectado el abonado.

Casa

Nota adhesiva

Cadencia trinnn .... trinnn 2 a 4s, 1 a 3s depende de la tecnología.

Casa

Nota adhesiva

Un mensaje al móvil que le indica que está haciendo timbrado al teléfono.

Casa

Nota adhesiva

El abonado B levanta el teléfono se va la corriente de timbrado cambia la impedancia, el sistema lo detecta, se envía una señal ANM (Answer Message) señal de respuesta.

Casa

Nota adhesiva

Hasta acá FACCH, se quitan los Stealing Flags y cambia a TCH y comienza la conversación.

Casa

Nota adhesiva

El nuevo tono lo mandan desde la MSC.

Casa

Nota adhesiva

Por qué es importante ANM, para poder switchear todo lo pendiente, indicar que todo el path de voz esta comunicado, conmutar la información. Charging, cobro se necesita para que la central comience tarificar, se registra en el CDR, cuando la llamada termina se cierra el CDR y se expulsa. CDR Call Detailed Record.

Call Management

MOBILE TO LAND CALL

Release -- Mobile Initiated

Under normal conditions, there are two basic ways a call concludes: mobile initiated and networkinitiated. In this scenario, we’ll assume that the mobile user initiates the release of this call. Anetwork initiated release is illustrated in the land-to-mobile scenario in the upcoming pages.

37 The mobile user initiates the conclusion of a call by pressing the "end" button (the buttonmight be labeled with a different term) on the mobile equipment. The mobile station sends adisconnect signal to the Mobile Switching Center (MSC).

38 The MSC, upon receiving this signal, sends a request to the Public Switched TelephoneNetwork (PSTN) to release the call. The actual type of message (or messages) sent to thePSTN depends on country (or possibly local) signaling conventions. This message could, forexample, be a clear-forward message (Q.721 - Q.725) or release message (Q.761 - Q.764).

39 The MSC asks the mobile station to begin its clear procedure.

40 After the mobile station has performed its clear procedure, it responds with the appropriateacknowledgment.

The above 4 steps causes a given instance of a call to be released. If the mobile station has one ormore other instances of a connection active between itself and the MSC (such a receiving a shortmessage or using the second B-channel for a data call), then the next three steps are not performed.

With respect to signaling, a mobile station can have several instances of calls (e.g., call waiting, 3-way call, short messages, and/or data call) all sharing the same MS-MSC dedicated signalingconnection. As mentioned earlier in this course, the Signaling Connection Control Part (SCCP)layer of the "A-interface" between the BSS and MSC is used in a connection oriented fashion. ASCCP connection is established when a MS first gains access to the network and is torn down whenall call activity instances have concluded.

41 Assuming that there are not more instances calls with this mobile station, the MSC sends aclear command to the BSS asking it to release all allocated dedicated resources for a givenSCCP connection.

42 The BSS instructs the mobile station to release from radio traffic channel. The mobile stationwill then go back to its idle mode of operation, which involves searching and retuning to thestrongest base station control channel.

43 The BSS acknowledges that it has released all allocated dedicated resources.

Version 1.0January 31, 1992 -- 15:54:05 [djw0640.txt]



Call Management

MOBILE TO LAND CALL

Release -- Mobile Initiated

43

40

......................................................................................................

......................................................................................................

38

39

37

Um A

......................................................................................................

....................................................................................................

MS BSS MSC PSTN

Disconnect

Release Complete

Channel Release

Release

Network Release

Clear Complete

Clear Command41

42




Casa

Nota adhesiva

El MS corta la comunicación, el abonado aprieta END.

Casa

Nota adhesiva

Para cortarse la comunicación, mensaje SS7 ISUP Release (REL)

Casa

Nota adhesiva

La central contesta después cuando ya libera contesta con Release Complete (RLC). El sistema libera toda la comunicación y ese comando es para liberar el canal TCH, este comando es un mensaje de señalización el que está activo es el TCH settea los Stealing Flags.

Casa

Nota adhesiva

Troncal libre, uno de los 30 canales de voz se va a liberar.

Call Management




Land to MobileCall Scenario




Call Management

PHASES OF A LAND TO MOBILE CALL




Call Management

PHASES OF A LAND TO MOBILE CALL

• Routing Analysis

• Paging


• Ciphering∗


• Call Setup

• Handover(s)∗

• Release





Call Management

LAND TO MOBILE CALL

Routing Analysis

The following is an example of an interprocessor message scenario for a land-to-mobile call. It isassumed that the mobile station is already registered with the system and has been allocated aTemporary Mobile Identification Number (TMSI).

0 A land-subscriber, or a mobile-subscriber in a different MSC, dials the directory number(MSISDN) of a mobile subscriber.

1 The PSTN routes the call to the Gateway MSC assigned this directory number. The directorynumber included in the message is referred to as the Mobile Subscriber ISDN number(MSISDN).

2a The MSC sends a message to the HLR requesting it to provide routing information for theMSISDN.

2b The HLR requests the VLR to allocate a Mobile Subscriber Roaming Number (MSRN) forthis call for this subscriber. This is the per-call MSRN allocation case.

2c The VLR allocates an MSRN and returns it to the HLR.

3a The HLR returns to the MSC a directory number where the mobile station can be reached.

3b The Gateway MSC sets up a voice call to the MSC currently serving the MS.

4 The MSC informs the VLR that a call with a particular MSRN is being terminated on thisMSC.

5 The VLR responds to the MSC by specifying which location area the mobile station is locatedand its Temporary Mobile Subscriber Identity (TMSI). Note, if a mobile station is barredfrom receiving calls or detached, the VLR would inform the MSC that a call cannot bedirected to the mobile station. The MSC, in turn, would connect the incoming call to anappropriate announcement.

Version 1.0February 4, 1993 -- 17:56:23 [rjt0641.txt]



Call Management

LAND TO MOBILE CALL

Routing Analysis

C D

MSC

5

4

3b

3a

2c

2b

1

2a

Perform Page

Incoming Call

Incoming Call on a Voice Trunk

Routing Information

Routing Information

...................................................................................................

...................................................................................................

...................................................................................................

...................................................................................................

...................................................................................................

PSTN HLRGateMSC

VLR

Get Route

Get Route

Incoming Call

Version 1.0February 4, 1993 -- 17:50:44 [rjt0641.pic]



Casa

Nota adhesiva

Abonado registrado, el sistema sabe donde esta el abonado. Cuando ingresa una comunicación el sistema debe saber donde esta el abonsado para hacer el paging, si el abonado no está registrado no va a recibir la comunicación, el abonado está registrado en la HLR que tiene en que VLR está, y en la VLR en que location area está el abonado.

Casa

Nota adhesiva

Call Management

LAND TO MOBILE CALL

Paging

6 The MSC uses the location area identity, provided by the VLR, to determine which BSSsshould page the mobile station. The MSC transmits a message to each of these BSSsrequesting that a page be performed. Included in the message is the TMSI of the mobilestation.

7 Each of the BSSs broadcasts the TMSI of the mobile in a page message on the paging channel.

8 When a mobile station hears its TMSI, or IMSI, broadcast on the paging channel, it respondswith a channel request message over a common access channel, Random Access Channel(RACH). The access scheme for this channel is similar in concept to slotted ALOHA.Although unlikely, it is possible that the mobile will have to retry this message several times.


10 The mobile station transmits a page response message to the base station over the SDCCH.Included in this message is the mobile station TMSI and Location Area Identification (LAI).This message also establishes a layer 2 signaling connection between the mobile station andthe base station.

11 The base station forwards the page response message to the MSC. This message also causesthe startup of a SCCP connection, if the mobile station does not have any other call instancesactive.

12 The MSC informs its VLR that a particular mobile station is responding to a page.




Call Management

LAND TO MOBILE CALL

Paging

12


9

Channel Request

Page

Perform Page

Page Response

Page Response

VLRMSCBSSMS

.......................................................................................

.........................................................................................

B AUm

6

8

7

.........................................................................................

.........................................................................................

Page Response10

11




Casa

Nota adhesiva

PCH

Casa

Nota adhesiva

RACH

Casa

Nota adhesiva

AGCH, se envía el # de canal SDCCH para que se comuniquen.

Casa

Nota adhesiva

Page response: el móvil dice yo estoy acá, no hay timbrado, se ha ubicado el móvil.

Call Management

Land to Mobile Call

Authentication

Since the air interface is vulnerable to fraudulent access, it is necessary to determine if the TMSIreceived from the mobile station is from the SIM that was assigned this TMSI.

Authentication is built around the notion that an Authentication Key (Ki) resides in only twoplaces: in an Authentication Center (AUC) and in the user’s SIM card. Since the authenticationkey is (or should) never be transmitted, it is virtually impossible for unauthorized individuals toobtain this key to impersonate a give mobile subscriber.

13 Three authentication parameters (referred to as "authentication triplets") are required by theVLR in order to authenticate a given mobile station: an authentication random number, anauthentication signed response, and a cipher key (RAND, SRES, and Kc). The VLR iscapable of requesting and storing up to five authentication triplets (per registered subscriber)from the AUC, via the mobile subscriber’s HLR.

In this scenario, we’ll assume that the VLR does not have any authentication triplets availablefor the TMSI requesting service. Since the mobile station is registered with the VLR, theVLR is capable of translating the mobile station’s TMSI into its IMSI. The VLR transmits arequest to the mobile station’s HLR requesting more authentication parameters. Included inthe message is the IMSI of the mobile station.


15 The AUC, using the IMSI, extracts the subscriber’s authentication key (Ki). The AUC thengenerates a random number (RAND), applies the Ki and RAND to both the authenticationalgorithm (A3) and the cipher key generation algorithm (A8) to produce an authenticationSigned Response (SRES) and a Cipher Key (Kc). The AUC then returns to the HLR anauthentication triplet: RAND, SRES, and Kc.

16 The HLR forwards the authentication triplets to the VLR.


18 The MSC forwards the authentication request message to the mobile station. The mobilestation reads its authentication key (Ki) from the SIM, applies the random number (RAND)and Ki to both its authentication algorithm (A3) and cipher key generation algorithm (A8) toproduce an authentication Signed Response (SRES) and Cipher Key (Kc). The mobile stationsaves Kc for later, and will use Kc when it receives command to cipher the channel.






Call Management

LAND TO MOBILE CALL

Authentication

20

19

18

17

16

15

14

13

.........................................................................................................

.........................................................................................................

.........................................................................................................

.......................................................................................................

.......................................................................................................







MSD

HLR AUCVLRB

MSC

GetAuthentication

Parameters

GetAuthentication

Parameters




Call Management

LAND TO MOBILE CALL

Ciphering









Call Management

LAND TO MOBILE CALL

Ciphering

25

Encipher Complete

Cipher ModeComplete

Cipher ModeCommand

Encipher Command

Set Ciphering

VLRMSCBSSMS

.................................................................

...................................................................

B AUm

21

23

22

...................................................................

...................................................................

24




Call Management

LAND TO MOBILE CALL


The purpose of the equipment validation phase is to read the mobile equipment serial number fromthe mobile station and check it against the Equipment Identity Register (EIR) to determine ifspecial action should be taken, such as deny service. Equipment validation is optional and iscontrolled by the service provider. Equipment validation is performed after the ciphering phaseand can be performed in parallel with call setup, or even be performed after the call is setup.

To keep the message flow diagrams clean in this scenario, the equipment validation phase is shownto occur before call setup. In real-life, the call setup phase will probably be performed immediatelyafter ciphering in order to keep call setup delays at a minimum. Equipment validation wouldtypically occur during call setup.

26 The MSC transmits a request to the mobile station requesting it to respond with itsInternational Mobile Equipment Identity (IMEI).

27 The mobile station upon receiving this request, reads its equipment serial number and returnsthis value to the MSC.

28 The MSC then requests the EIR to check the IMEI for validity. The EIR will first check to seeif the IMEI value is within a valid range. If so, it then check so see if the IMEI is on a suspector known list of invalid equipment.

29 The EIR returns to the MSC the results of the IMEI validation. If the results are negative, theMSC might abort the call or possibly let the call continue but inform the network serviceprovider of the event. In this scenario, we’ll assume that the IMEI is valid.




Call Management

LAND TO MOBILE CALL


29

IMEI Request

EIRMSC MS

...................................................................

26

28

27

...................................................................

...................................................................

IMEI Response

Check IMEI

IMEI CheckResults




Call Management

LAND TO MOBILE CALL


30 After the MSC receives the Encipher complete message from the mobile station, the mobilestation is informed that a call will be setup via a setup message.

31 The mobile station, upon receiving a setup message, performs compatibility checking beforeresponding to the setup message--it is possible that the mobile station might be incompatiblefor certain types of call setups. Assuming that the mobile station passes compatibilitychecking, it acknowledges the call setup with a setup confirm message.

32 The MSC selects a trunk (terrestrial channel) to the BSS. The MSC then sends an assignmentrequest message to the BSS requesting it to assign a radio resource. Included in the messageare attributes describing the type of radio resource to be allocated and the trunk (terrestrialchannel) to be used.

33 The BSS upon receiving an assignment request message allocates an appropriate radio trafficchannel and transmits an assignment command over the Stand-alone Dedicated ControlChannel (SDCCH) to the mobile station informing it to change to a new radio channelconfiguration.

34 The mobile station tunes to the specified traffic channel and transmits an assignment completemessage back to the BSS. The mobile station then begins alerting the user (i.e., the phonerings). Prior to this point in time, the mobile station user is unaware that he/she is receiving acall. The mobile station no longer uses the SDCCH after receiving a traffic channelassignment.

35 The BSS upon receiving the assignment complete message connects the assigned trafficchannel to the trunk (terrestrial facility) that was allocated by the MSC. The BSS places theSDCCH on a free list and transmits an assignment complete message to the MSC.

It was assumed in the past 3 steps that the BSS had no complications in assigning andconnecting a radio traffic channel to the specified trunk. Several possible errors include: noradio resource available, equipment failure, requested transcoding/rate adaption unavailable,and terrestrial resource already allocated. If any of these or other errors occur, the BSS wouldsend an assignment failure message to the MSC.




Call Management

LAND TO MOBILE CALL


35

Call Setup Confirm

Assign Trunk &Radio Channel

Assign RadioChannel

Call Setup

Trunk & RadioAssignmentComplete

Radio AssignmentComplete

MSCBSS MS

.................................................................................

30

32

31

.................................................................................

.................................................................................

33

34




Casa

Nota adhesiva

SDCCH

Casa

Nota adhesiva

Muere el SDCCH

Casa

Nota adhesiva

TCH se convierte en FACH por los Stealing Flags.

Call Management

LAND TO MOBILE CALL


36 As discussed with the previous vu-graph, the mobile station will begin alerting the user after itreceives a traffic channel assignment. Once alerting has begun, the mobile station sends analerting message to the MSC.

37 The MSC, upon receiving an alerting indication from the mobile station, would begin playingaudible ringing to the calling party and sends a network alerting message to the PublicSwitched Telephone Network (PSTN). Prior to this point, the calling party heard silence.

At this point in the call, the mobile station is alerting the called party and audible is being played tothe calling party. One of three events can occur: calling party hangs-up, mobile subscriber answersthe phone, or the MSC times-out waiting for the mobile subscriber to answer. Since a radio trafficchannel is a valuable resource, GSM does not allow a mobile station to ring forever.

38 In this scenario, it is assumed that the mobile subscriber answers the phone. The mobilestation, in response to this action stops alerting and sends a connect message to the MSC.

39 The MSC removes audible to the PSTN and connects the PSTN trunk to the BSS trunk(terrestrial channel), and sends a connect message to the PSTN. The caller and called partynow have a complete talk path. This event typically denotes the beginning of the call forbilling purposes.

40 The MSC sends the mobile station a connect acknowledgement message.




Call Management

LAND TO MOBILE CALL


40

Network Alerting

Connect (off-hook)

Connect

Mobile Alerting

ConnectAcknowledge

PSTNMSC MS

....................................................................

36

38

37

....................................................................

....................................................................

39




Casa

Nota adhesiva

El móvil indica que va a timbra, es un mensaje, esta libre es un mensaje ACM, en ese momento el MSC manda el Ring Back Tone

Casa

Nota adhesiva

Libera el FACCH y comienza a conversar.

Call Management

LAND TO MOBILE CALL

Release -- Network Initiated

Under normal conditions, there are two basic ways a call concludes: mobile initiated and networkinitiated. In this scenario, we’ll assume that the user on the land network side initiates the releaseof this call. A mobile initiated release was illustrated in the previous mobile-to-land scenario.

41 The calling user hangs up resulting in the PSTN to send a network release signal to the MSC.The actual type of message (or messages) received from the remote exchange depends oncountry (or possibly local) signaling conventions. This message could, for example, be aclear-forward message (Q.721 - Q.725) or release message (Q.761 - Q.764).

42 The MSC asks the mobile station to begin its clear procedure.

43 The mobile station informs the MSC that it has started its clear procedure.

44 The MSC acknowledges receiving the mobile station release message. The mobile stationcompletes its clear procedure.

The above 4 steps causes a given instance of a call to be released. If the mobile station has one ormore other instances of a connection active between itself and the MSC (such a receiving a shortmessage or has another call on hold), then the next three steps are not performed.

With respect to signaling, a mobile station can have several instances of calls (e.g., call waiting, 3-way call, short messages, and/or data call) all sharing the same MS-MSC dedicated signalingconnection. As mentioned earlier in this course, the Signaling Connection Control Part (SCCP)layer of the "A-interface" between the BSS and MSC is used in a connection oriented fashion. ASCCP connection is established when a MS first gains access to the network and is torn down whenall call activity instances have concluded.

45 Assuming that there are not more instances of calls with this mobile station, the MSC sends aclear command to the BSS asking it to release all allocated dedicated resources for a givenSCCP connection.

46 The BSS instructs the mobile station to release from radio traffic channel. The mobile stationwill then go back to its idle mode of operation, which involves searching and retuning to thestrongest base station control channel.

47 The BSS acknowledges that it has released all allocated dedicated resources.

Version 1.0January 31, 1992 -- 15:53:00 [djw0648.txt]



Call Management

LAND TO MOBILE CALL

Release -- Network Initiated

47

46

45Clear Command

Clear Complete

Network Release

Release

Channel Release

Release Complete

Disconnect

PSTNMSCBSS MS

....................................................................................................

......................................................................................................

AUm

41

43

42

......................................................................................................

......................................................................................................

44




Casa

Nota adhesiva

Libera canal TCH

Call Management




Mobile to MobileCall Scenario




Call Management

PHASES OF A MOBILE TO MOBILE CALL




Call Management

PHASES OF A MOBILE TO MOBILE CALL

.

- Release

- Handover(s) *

- Request for Service

- Routing Analysis

- Paging

- Ciphering*

- Equipment Validation *

- Call Setup

- Authentication *

- Ciphering*

- Equipment Validation *

- Call Setup

- Authentication *

Phase might not occur*

TerminatingMobile

OriginatingMobile




Casa

Nota adhesiva

Analiza la ruta, analiza el #B donde va.

Call Management




Handover Overview




Call Management

WHY HANDOVER?




Call Management

WHY HANDOVER?

MSC

PSTNI can’thearyou!!!

CurrentVoice Path

CurrentRadio Path

Version 1.0March 2, 1992 -- 14:24:36 [djw1045.eps]



Call Management

HANDOVER OPPORTUNITY WINDOW

The signal strength and quality on the Handover Candidate cell should be significantly better thanthe signal on the currently serving cell before an handover for signal strenght reasons is performed.This helps avoid "looping handovers" where the MS handed back and forth between a pair of cellswith no real difference in quality of signal. Therefore, the signal threshold used to beginHandovers is usually lower than the signal threshold used to qualify Candidate cells. However,there is a minimal acceptable signal strength and quality on the current serving cell since theHandover message must be sent and recieved clearly enough to be understood.

The Handover thresholds can be set on a per BTS (Cell) basis and the "art" of tuning the parametersto get the most out of the network is a difficult and demanding process.

Version 1.0February 4, 1993 -- 18:04:11 [rjthoow.txt]



Call Management

HANDOVER OPPORTUNITY WINDOW

BTS A BTS B

SignalStrength

SignalStrength

BTSA

BTSBDistance

Minimum AcceptableSignal for Handover

EarliestHandover

Opportunity

LatestHandover

Opportunity

HandoverOpportunity

Window

Version 1.0May 5, 1992 -- 18:53:06 [djw1080.eps]



Call Management

HANDOVER PROCESS




Call Management

HANDOVER PROCESS

• Measurement of radio signal strength andquality

• Analysis of signal strength and quality anddecision whether handover should beperformed

• Execution of handover

Version 1.0March 30, 1992 -- 15:34:29 [djw0403.pic]



Call Management

MOBILE STATION MEASUREMENT PROCESSFOR HANDOVER -- EXAMPLE

While a mobile station is active on a traffic channel, it has the responsibility of providing signalstrength and signal quality measurement data to its serving Base Transceiver Station (BTS) so thatthe serving Base Station Controller (BSC) can decide if a handover should be performed. Thesemeasurement reports are from the mobile station’s reference point and represent the strength of thesignal being received from its serving BTS, plus the signal strength of the neighboring BTSdownlink (i.e., BTS-to-mobile direction) control channels. The mobile station, by periodicallysampling and reporting the signal strength of neighboring BTS control channels, is able to providevaluable information to the serving BSC, so that it can determine when a handover should beperformed. As a mobile station moves away from its serving BTS towards the coverage area ofneighboring BTSs, the mobile station measurement reports will show a gradual decrease in signalstrength from its serving BTS while showing an increase in measured signal strength from one ormore neighboring BTSs.

It is the responsibility of the serving BSC to analyze the signal strength measurement reports fromthe mobile station and decides when a handover should be performed. If it is determined that thereis a better BTS to serve the call, the serving BSC initiates the handover procedure.

The figure on the following page shows a cellular grid consisting of 17 cell areas. (For ease ofdiscussion, a cell number has been added to the bottom of each antenna tower.) Each BTS has abroadcast control channel.

more to be added later




Call Management

MOBILE STATION MEASUREMENT PROCESSFOR HANDOVER -- EXAMPLE

17

151413

10 11 129

4 5

1 2 3

6 7 8

16

2142

91 80

15

F29,S3

19 4839

41 33 104 56 120

74522

61

Mobile Station Traffic Channel = Freq 29, Slot 3

Mobile Station Monitors: F91, F80, F61, F39,F15, F19, F41, F33,F104, F56, F22

BTS




Call Management

FACTORS THAT CAN INFLUENCETHE DECISION TO HANDOVER

When a mobile station is active on a call, the serving base station has the responsibility of deciding when ahandover should be performed.

The GSM specification DOES NOT provide specific rules/requirements as to how a base station shoulddecide when a handover should be performed. In general, each base station will contain handover criteriaalgorithms. An important input to these algorithms are signal level thresholds, which can be modified by theservice provider. If the signal level strength of a mobile station’s radio channel falls below a given threshold,the base station will use information in the mobile station’s measurement reports to see if any other basestation(s) are in a better position to serve the call.

The following diagram list some of the most probable conditions (this is not intended to be a complete list).

Poor Signal StrengthIn a typical system, this will probably be the most frequent condition that will trigger a handover. The basestation, in reviewing signal strength measurement data, decides that there is a better base station candidatethat can serve the mobile station. In order for a "poor signal strength" condition to result in a handover, theremust be a well qualified candidate base station. If there are no candidates, no handover attempt is made. Theserving base station uses the signal strength data of neighboring base stations, supplied in the mobile station’smeasurement reports, to determine if there is a qualified candidate.

Poor Signal QualityIt is possible that the signal strength being received by both the mobile station and base station is satisfactory,but the quality of the signal is poor--too many bits being received are in error. One possible situation that cancause this condition is co-channel interference from a distant base station. For this condition, it is unlikelyany neighboring base station will be likely candidates to serve the mobile, especially if the signal strength isgood. What the serving base station can do, in an effort to escape from the co-channel interferer, is to havethe mobile hand off to a new frequency and timeslot on the same base station (intra Base Transceiver Station(BTS) handover).

Better CandidateIt is also possible that both the signal strength and signal quality received by the base station and mobilestation are satisfactory, however, the measurement reports from the mobile station indicate that there is aneighboring base station who could better serve the mobile station (with regards to signal strength) than thecurrent serving base station. It is advantageous to keep both mobile stations and base stations transmitting attheir lowest power level (assuming the power levels of both the mobile and base station can be dynamicallycontrolled).

Traffic BalancingTraffic balancing is more of a strategy than a condition with a goal to minimize blocking of radio channels inkey cell areas by forcing handovers to another cell area that has under utilized radios. For base stations thatare being used as overlaid cells (an inner small cell and an outer regular size cell), it is desirable to hand off acall from the "outer server group" to the "inner server group" for situations where the mobile is movingtowards the base station antenna.

Version 1.0May 26, 1992 -- 17:26:44 [djw0605.txt]



Call Management

FACTORS THAT CAN INFLUENCETHE DECISION TO HANDOVER

• Poor signal strength

• Poor quality of signal

• Better candidate

• Traffic Balancing

Version 1.0October 7, 1991 -- 12:35:35 [djw0605.pic]



Call Management

HANDOVER TYPES

4 LEVELS

The type of handover procedure executed depends on what level of switching must be performed inorder to move the call from the serving BTS to the new candidate BTS.

There are basically two levels of handovers: internal and external handovers. If the serving andcandidate BTSs reside within the same Base Station System (BSS), BSC for the BSS can performthe handover without the involvement of the Mobile Switching Center (MSC); thus termed internalor intra-BSS handover.

If the serving and candidate BTSs do not reside within the same BSS, then an external handover isperformed, which requires the MSC to coordinate and switch facilities (handoff the call) betweenthe serving BTS and the candidate BTS.




Call Management

HANDOVER TYPES

4 LEVELS

• Internal Handover (Intra-BSS)

– within same Base Tranceiver Station(BTS) - Rare, normally due to frequencyinterference that is avoided simply bychanging frequencies.

– between different BTSs - More likely,due to moving mobile.

• External Handover (Inter-BSS)

– between BTSs on different BSSs withinsame MSC (intra-MSC) - moving mobile

– between BTSs on different BSSs ondifferent MSCs (inter-MSC) - movingmobile

Version 1.0February 4, 1993 -- 18:07:47 [rjt0546.pic]



Call Management

EXAMPLE OF DIFFERENT HANDOVER TYPES

The following vu-graph is intended to help illustrate the 4 types (levels) of handover. Illustrated is a systemconsisting of two Mobile Switching Centers (MSCs) with three Base Station Systems (BSSs). Also depictedare cell coverage areas with example global cell identification codes for each Base Transceiver Station(BTS).

Assume that the mobile and land stations are active in a call, the call is being controlled by MSC A, and themobile is currently in cell area 234-01-10-51.

Intra-BSS, Intra BTS (internal handover)For this type of handover, the mobile station is handed off to a different radio channel within the same cellarea: 234-01-10-51. This is actually an unusual type of handover, since it is typically not triggered by poorsignal strength--if it was, the candidate cell area would probably be different from the current serving cellarea. A probably cause for this type of handover would be poor signal quality (not strength), possibly due toco-channel interference. For this type of handover, BSC 2 would allocate a new radio channel and instructthe mobile station to retune.

Intra-BSS, Inter BTS (internal handover)Say the mobile station moves from area 234-01-10-51 towards area 234-01-10-52. At some point in time,BSC 2 will determine from the signal strength measurement reports that the base station responsible for cellarea 234-01-10-52 can better serve the call. Since the candidate cell area is also connected to BSC 2, thehandover can be coordinated by BSC 2 without the involvement of MSC A. In this situation, BSC 2 reservesan available radio channel from cell area 234-01-10-52 and instructs the mobile station to retune to the newradio channel. BSC 2 is also responsible for switching the voice path between MSC A and the old radiochannel to the new radio channel.

Inter-BSS, Intra MSC (external handover)Say the mobile station moves from area 234-01-10-51 towards area 234-01-10-55. At some point in time,BSC 2 will determine from the signal strength measurement reports that the base station responsible for cellarea 234-01-10-55 can better serve the call. BSC 2 will then determine that there are no base stationsconnected to it that serves area 234-01-10-55 and will request MSC A to arrange the handover to thecandidate cell area. MSC A will determine that BSC 3 is responsible for cell area 234-01-10-55 and requestit to reserve a free radio channel for a handover. MSC A will relay the new radio channel information backto BSC 2. BSC 2 will then ask the mobile to retune to the new channel. At the same time, MSC A willswitch voice paths between the Public Switched Telephone Network (PSTN) and the old BSC (BSC 2) to thenew BSC.

Inter-BSS, Inter MSC (external handover)Say the mobile station moves from area 234-01-10-51 towards area 234-01-89-21. Similar to previousscenario, BSC 2 will ask MSC A to coordinate the handover to 234-01-89-21. MSC A will determine that ithas no base stations under its control responsible for the identified cell area. MSC A then needs to determinewhich neighboring MSC is responsible for the cell area, in this case MSC B, and will ask it to receive ahandover.

Note: from the mobile station’s reference point, it is unaware of the 4 levels of handover. The mobile stationhas two handover related responsibilities: provide signal strength measurements to its serving base stationand to retune to a new radio channel when ordered to do so.




Call Management

EXAMPLE OF DIFFERENT HANDOVER TYPES

MSCB

MSCA

PSTN

MSC-BSS Trunks

Inter-office Trunks

BSC2 BSC

3

BSC1

234-01-10-54

234-01-10-55

234-01-10-52

234-01-10-51

234-01-10-50

234-01-89-20

234-01-89-21

234-01-89-22

234-01-10-53

LandStation

MobileCountryCode

MobileNetwork

Code

LocationAreaCode

CellIdentity

Global Cell Identification

Version 1.0April 16, 1992 -- 00:41:06 [djw1094.eps]



Call Management

INTRA-MSC INTER-BSS HANDOVER STEPS

Provided in the next two vu-graphs is a decomposition of an intra-MSC handover into four basic steps, froma voice path resource perspective. A detailed message exchange scenario between network elements can befound on Page 4-104.

It is assumed in this scenario that a call has already been established between a mobile station and a fixedstation, with the solid path representing the voice path. Both BSS 1 and BSS 2 are connected to the MSC.

BSS 1 and BSS 2 could be in the same Location Area, but let’s assume each BSS is in a different LocationArea for this example.

Step 1: Handover Request from BSS

• Mobile station provides signal strength and signal quality measurements to BSS 1. BSS 1 is alsomeasuring the strength of the signal received from the mobile.

• BSS 1, in reviewing signal strength data, makes the decision that a handover should be performed. BSS1 reviews the qualified cell areas that are candidates to receive the call and determines that none of thebest candidates are associated with Base Transceiver Stations (BTSs) that in controls. Thus, we have anexternal handover condition.

• BSS 1 sends a handover request to the MSC with a rank-ordered list of candidate cells that are qualifiedto receive the call.

Step 2: Allocation of New Resources

• The rank-ordered list of handover candidate cells can contain as few as one member, or several membersif the mobile is on a cell border adjacent to several cells. If the rank-ordered list contains severalcandidate cells, the MSC attempts to reserve resources for the best candidate. If unsuccessful, the MSCwill then attempt to reserve resources for the next best candidate. This process continues until either theproper resources can be reserved for a given candidate or the candidate-list is exhausted. If the MSCcannot arrange the handover, BSS 1 is informed of the situation and BSS 1 continues to maintain thecall.

• The MSC reviews the global cell identity associated the best candidate to determine if one of the BSSsthat it controls is responsible for the cell area. In this scenario, the MSC determines that the cell area isassociated with BSS 2.

• To perform an intra-MSC handover, two resources must be reserved: a trunk between the MSC and thenew BSS, and a radio traffic channel in the new cell area. The MSC is responsible for managing trunkresources. The BSS is responsible for managing radio resources.

• The MSC reserves a trunk to BSS 2 and sends a handover request message to BSS 2. Included in thismessage is the desired cell area for handover, the identity of the MSC-BSS trunk that was reserved, andthe radio-path encryption (ciphering) key, Kc, (so that the rado-path can continue be encrypted one themobile station is asked to handover).

• BSS 2 reserves a radio traffic channel for the BTS that is associated with the specified candidate cellarea and connects the selected radio the to MSC-BSS trunk previously reserved. BSS 2 then return ahandover acknowledge to the MSC with the radio channel that has been reserved.

Version 1.0December 30, 1992 -- 12:25:58 [djw1024.txt]



Call Management




PSTN

PSTN

MSC

MSC

BSS 1

BSS 1

BSS 2

BSS 2

Presentvoice path

Futurevoice path

Version 1.0January 5, 1992 -- 20:20:25 [djw1024.eps]



Call Management


CONTINUED

Step 3: Handover Execution

• If an intra-MSC handover reaches this step, all necessary resources have been reserved to perform ahandover to one of the candidate cell areas.

• The MSC instructs BSS 1 to send a handover command to the mobile station. Included in this commandis the radio traffic channel number that was reserved within BSS 2.

• The mobile station retunes and begins transmitting special access messages on the new radio channel.

• BSS 2 informs the MSC when it begins detecting the mobile handing over.

• BSS 2 and the mobile station exchange messages to synchronize/align the mobile station’s transmissionin the proper timeslot.

• In parallel, the MSC switches voice paths to BSS 2.

Step 4: Release of Old Resources

• Once the mobile station and BSS 2 synchronize their transmission and establish a new signalingconnection, BSS 2 informs the MSC that the handover has been successfully completed.

• The MSC frees up the old terrestrial facility to BSS 1 and sends a request to BSS 1 to release to oldradio traffic channel.

• At this point, BSS 1 has freed up all resources associated with the mobile station. These resource arenow available for a new call or to receive a handover.

It is stated in the GSM recommendations that the "open interval gap" during handover should not exceed 150milliseconds for 90% of all handovers. The open interval gap starts in step 3 when the mobile station retunesto the new radio channel and concludes with the mobile station, after synchronizing, is incurring no loss invoice/data transmission in the BSS or MSC.

Misc.: Call Torn Down - Location Update

Since we assumed that BSS 1 and BSS 2 were in different Location Areas, the mobile must do a LocationUpdate to notify the VLR and HLR (if necessary) that they have moved into a new Location Area. LocationUpdates are never done during a call. Once the call is completely torn down (the radio traffic channel isreleased), the Mobile will resume listening to the broadcast channel and will notice that the LAC stored in theSIM memory is different than the LAC on the broadcast channel. This triggers the geographic LocationUpdate process to begin.

Version 1.0December 30, 1992 -- 12:31:16 [djw1025.txt]



Call Management


CONTINUED



PSTN

PSTN

MSC

MSC

BSS 1

BSS 1

BSS 2

BSS 2

Oldvoice path

Newvoice path

Version 1.0January 5, 1992 -- 20:20:29 [djw1025.eps]



Call Management

HANDOVER OPEN INTERVAL GAPExample

It is specified in the GSM recommendations that the maximum duration of interruption to a call dueto a single handover shall not exceed 150 milliseconds for 90% of all cases.1 It is also specifiedthat if there are several short breaks during a single handover, the sum total of all breaks should notexceed 150 milliseconds.2

Illustrated on the following page is an example showing three components to the overall handoveropen interval gap. In this example, it is assumed the MSC "hot switches" voice facilities from theold BSS to the new BSS and that the MSC uses the handover detect indication from the new BSSto synchronize switching the paths.

How and when a MSC switches facility paths between the old and new BSS is an internal MSCdetail. The GSM recommendations does not tie an MSC vendor to any specific method, other thanrequiring that the MSC component not push the overall open interval gap beyond 150 millisecond.For example, the following list identifies three different ways for a MSC to switch facilitiesbetween an old and new BSS:

• The MSC can synchronize the hot switching of facilities on receipt of a handover detectindication from the new BSS (as illustrated on the other page).

• The MSC can synchronize the hot switching of the facilities on receipt of the handovercomplete indication from the new BSS.

• The MSC can use a 3-party bridge connection between the old and new BSS and use thehandover complete indication to release the old BSS from the 3-party bridge.3 The benefit ofusing a 3-party bridge connection is that the MSC does not contribute to the overall openinterval gap.

1 . Reference: GSM 2.08, Version 3.0.0, Section 4.1.9, Page 8, and Section 2, Page 2.2 . Reference: GSM 2.08, Version 3.0.0, Section 3.1.9, Page 5.3 . Reference: GSM 3.09, Version 3.1.0, Section 2.1, Page 5.




Call Management

HANDOVER OPEN INTERVAL GAPExample

Maximum open interval gap = 150 milliseconds

Mobile StationRetuning/Synchronizing

MSC SwitchingVoice Paths

BSS SignalingDelay

Time

Old BSS ordersmobile stationto handover

New BSSdetects

beginningof handover

Mobile stationhandovercomplete.

Begins transmittinguser voice/data

MSC completesswitching voicepath (no loss

in mobile stationvoice/data)

MSC receiveshandover

detectindication

from new BSS

Version 1.0April 17, 1992 -- 12:31:05 [djw1095.eps]



Call Management

INTER-MSC HANDOVER TYPES




Call Management

INTER-MSC HANDOVER TYPES

• Basic Handover

Call is handed from controlling MSC toanother MSC

• Subsequent Handover

Call is handed from 2nd MSC to anotherMSC




Call Management

BASIC INTER-MSC HANDOVER STEPS

A four step decomposition of a basic inter-MSC handover is provided, from a voice path resourceperspective, in the next two vu-graphs. A very detailed message exchange scenario, from a signalingperspective, can be found starting on Page 4-110.

It is assumed in this scenario that a call has already been established between a mobile station and a fixedstation, with the wide solid path representing the voice path. BSS A is connected to MSC A and BSS B isconnected to MSC B.


• The sequence of events leading up to an MSC receiving a handover request from a BSS for an intra-MSC handover is exactly the same for an inter-MSC handover. BSSs do not know the differencebetween an intra-MSC and inter-MSC handover.

• Since the events associated with this step were described in the intra-MSC handover scenario, thesesteps will not be redescribed here. See Page 4-66 for details.




Call Management


FutureTalk Path

PresentTalk Path


BSS A

BSS B

BSS A

BSS B

MSC B

MSC A

MSC B

MSC A

..............

MS

PSTN


..............

MS

PSTN




Call Management


Continued




Call Management


Continued

New TalkPath

Old TalkPath

BSS A


..........

........

MS

PSTN


MSC B

MSC A

MSC B

MSC A

..........

........

MS

PSTN

BSS B

BSS A

BSS B




Call Management

SUBSEQUENT INTER-MSC HANDOVER STEPS

Handback




Call Management


Handback

Futuretalk path

Presenttalk path

........

........

.


PSTN

MS..........

........

MSC A

MSC B

MSC A

MSC B

BSS B

BSS A

BSS A

BSS B


PSTN

MS




Call Management


Handback -- Continued




Call Management


Handback -- Continued

..............

MS

PSTN


MSC B

MSC A

MSC B

MSC A

..............

MS

PSTN

Step 3: Handover ExecutionNew talk

path

Old talkpath

BSS A

BSS B

BSS A

BSS B




Call Management

SUBSEQUENT INTER-MSC HANDOVER EXERCISE

3rd MSC




Call Management


3rd MSC

How are MSCinterconnected?

Futuretalk path

Presenttalk pathStep 1: Handover Request from BSS


MSC C

MSC A

..........

........

MS

PSTN

BSS C

BSS B

BSS A

MSC B

MSC B

BSS A

BSS B

BSS C

PSTN

MS..........

........

MSC A

MSC C




Call Management


3rd MSC -- Continued




Call Management


3rd MSC -- Continued

New talkpath

Old talkpath

MSC C

MSC A

..............................

MS

PSTN

BSS C

BSS B

BSS A

MSC B

MSC C

MSC A

...............................

MS

PSTN

BSS C

BSS B

BSS A

MSC B






Call Management

INTER-MSC HANDOVER VOICE FACILITIES

The voice path for inter-Mobile Switching Center (MSC) handovers can be over dedicated point-to-point trunks, via the Public Switched Telephone Network (PSTN), a tandem switch, or anycombination of these. In any of these cases, the signaling used to setup inter-MSC voice facilitiesis the same! This is wonderful!

When a call is handed over from MSC A to MSC B, for example via the PSTN, MSC A sets up ainter-MSC voice connection by placing a call to a directory number that belongs to MSC B. WhenMSC A places this call, the PSTN is unaware the call is a handover and follows normal call routingprocedures and delivers the call to MSC B.

Full interconnectivity between all MSCs in the example requires a total of 6 paths. The number ofinterconnecting paths grows rapidly as one introduces more MSCs based on the following formula:

Number of paths = N ( N - 1 ) / 2

where N = the number of MSCs.




Call Management

INTER-MSC HANDOVER VOICE FACILITIES

MSCD

PSTN

MSCC

MSCA

MSCB

MSCD

PSTN

MSCC

MSCA

VIA PSTN FACILITIES

VIA DEDICATED FACILITIES

PSTN Trunks

Inter-MSC Trunks

MSCB




Call Management

MSC DIRECTORY NUMBER SPECTRUM




Call Management

MSC DIRECTORY NUMBER SPECTRUM

Used to referenceinter-MSC handovers

Used to referencevisiting subscribers

Used to referencehome subscribers

MSRN

MSHN

MSISDN

Trunks

Trunks

LOCALEXCHANGE

MSC

MSC

PSTN

Directory Number Spectrum




Call Management

INTER-MSC SIGNALING




Call Management

INTER-MSC SIGNALING

ISDN-UP = ISDN User PartTUP = Telephone User Part

.............................

........

........

..

Inter-office signalingsuch as ISDN-UP or TUP

(outside scope of GSM specification)

..............

Mobile Application Part (MAP)(defined in GSM specification 9.02)

PSTN

E

or

MSCB

MSCA




Call Management

BASIC INTER-MSC HANDOVER

Initial Condition




Call Management


Initial Condition

MSCB

MSCA

BSSB2

BSSA

BSSB1

VLRB

PSTN

Serving CellGlobal Cell ID

234-01-35-43Candidate CellGlobal Cell ID

234-01-20-65

Talk Path

720-1234

Version 1.0March 2, 1993 -- 13:21:16 [rjt1109.prn]



Call Management


Handover Number Allocation

Version 1.0October 8, 1991 -- 18:06:03 [djw1110.txt]



Call Management


Handover Number Allocation

MSCB

MSCA

BSSB2

BSSA

BSSB1

VLRB

PSTN



234-01-20-65

PSTN/ISDN Interface

E Interface

Perform Handover(234-02-20-65, Kc)

Perform Handover Ack.(219-9221, <radio channel x>)

720-1234




Call Management


Inter-MSC Trunk Setup




Call Management


Inter-MSC Trunk Setup

MSCB

MSCA

BSSB2

BSSA

BSSB1

VLRB

PSTN



234-01-20-65

PSTN/ISDN Interface

E Interface

Network Setup(219-9221)

Setup Complete

720-1234




Call Management


Facilities Before Handover




Call Management


Facilities Before Handover

MSCB

MSCA

BSSB2

BSSA

BSSB1

VLRB

PSTN

PSTN/ISDN Interface

E Interface

Future talk path

720-1234




Call Management


Events After Handover Command




Call Management


Events After Handover Command

MSCB

MSCA

BSSB2

BSSA

BSSB1

VLRB

PSTN

PSTN/ISDN Interface

E Interface

Send end signal

Answer

New talk path

Old talkpath

Hand

over

Com

man

d

(retu

neto

chan

nel

x)

720-1234




Call Management




Handover Scenarios




Call Management

INTRA-BSS HANDOVER

The opposite page diagram shows an intra-BSS handover.

1 Mobile Stations monitor up to six other cells as well as the serving cell. The measurements oncandidate cells are taken in the 2 to 6 ms of free time between transmitting and receivingtraffic for the active call. This requires the MS to retune to many frequencies very quickly.These measurements are reported to the BSS between 1 to 2 times a second (depending onother activities occurring on the signaling channel used to transmit the measurements). Whilethe MS can only measure the quality of the radio signal in the BSS to MS direction, it isassumed that quality of the signal is similar for both directions.

2 The BSS monitors the signal strength measurements for the active cell and the candidate cellsand makes a decision to Handover for a variety of reasons (e.g., traffic balancing, signalstrength, etc.). The Handover Command tells the MS that a HO is beginning and provides thebroadcast or beacon frequency of the new cell and a Handover reference number.

3 The MS sends a Handover Access on the new cell’s common channel and identifies itself withthe Handover reference number.

4 The new Cell responds with the traffic channel assignment (frequency and time slot).

5 The mobile retunes to the traffic and associated signaling channel and sends a HandoverComplete to the BSS.

6 The BSS sends a Handover Performed message to the MSC to trigger call record data andHandover Peg counts.

BSS - Base Station SystemMS - Mobile StationMSC - Mobile Switching Center




Call Management

INTRA-BSS HANDOVER

6

5

4

3Handover Access

Handover Complete

HandoverPerformed

Physical ChannelInformation

1

Signal StrengthMeasurements

BSS MSCUm A

MS

Handover Command

...............................................................................

...............................................................................

...............................................................................

2




Call Management

INTRA-MSC HANDOVER

Steps 1 & 2

The opposite page diagram shows an inter-BSS, intra-BSS handover.


2 The BSS monitors the signal strength measurements for the active cell and the candidate cellsand makes a decision to Handover for a variety of reasons (e.g., traffic balancing, signalstrength, etc.). If the best candidate cell is not within this BSS, the MSC is requested tocoordinate the Handover through a Handover Required message. The message includes a listof up to three candidate cells.

3 The MSC evaluates the candidates and chooses the best one. A Handover Request message issent to the new BSS with the candidate cell identified.

4 The new BSS determines if the candidate cell can support additional calls and if so, returns thegeneral frequency to be used and the Handover reference number for this Handover.

5 The MSC tells the BSS to begin the Handover and provides the candidate cell frequency andHandover reference number.

6 The old BSS passes the Handover Command onto the MS. This results in the MS beginningthe retuning process.





Call Management

INTRA-MSC HANDOVER

Steps 1 & 2

6

2

Handover RequestAcknowledge

Handover Request

Handover Command

Handover Command

Handover Required

..............................................................................

..............................................................................

............................................................................

..............................................................................

Signal StrengthMeasurements1

MSA AUm

NewBSS

MSCOldBSS

3

4

5




Call Management

INTRA-MSC HANDOVER

Steps 3 & 4



9 The new BSS notifies the MSC that the Handover has reached this point and the MSC beginsthe reconfiguration of the voice path to the new BSS.

10 The mobile retunes to the traffic and associated signaling channel and sends a HandoverComplete to the BSS.

11 The BSS sends a Handover Complete message to the MSC to trigger call record data andHandover Peg counts. In addition, it triggers the MSC to initiate clearing of facilities to andon the old BSS.

12 The MSC tells the old BSS to release the radio channel and associated BSS to MSC trunk.

13 The old BSS releases the radio channel and trunk and informs the MSC.





Call Management

INTRA-MSC HANDOVER

Steps 3 & 4

10

9

OldBSS

MSC NewBSS

Um A A

MS

7 Handover Access...........................................................................................

.........................................................................................

...........................................................................................

12

13

...........................................................................................


Release RadioChannel

Radio ChannelReleased

Handover Detected

Handover Complete

Handover Complete

8

11




Call Management

INTER-MSC HANDOVER

Basic -- Steps 1 & 2

The opposite pages diagrams show an inter-MSC handover.



3 The MSC evaluates the candidates and chooses the best one. In this case, the best candidate isin another MSC area. A MAP message is sent to MSC B requesting a Handover to a specifiedcell on MSC B.

4 Because Handover between switches will require voice trunks between the switches, aHandover Number (MSHN) is allocated for this handover. This is similar to the MSRNallocated for the termination of a mobile call. Number allocation is specified as a VLR entityoperation and the diagram shows a message flow between the MSC and VLR entities.

5 See item 4 above.

6 A Handover Request message is sent to the new BSS with the candidate cell identified.


8 MSC B responds to MSC A with an acknowledgement of the Handover Perform and providesthe information needed by the MSC (MSHN) and MS (frequency, Handover referencenumber, etc.).

9 MSC A initiates the process to set up a voice path between MSC A and MSC B in order tosupport the path switching when the Handover occurs. MSC A sets up a call using the MSHNprovided above.

10 MSC B responds to the trunk set up attempt as appropriate for the trunk signaling used for thattrunk. In addition, MSC B notes the MSHN and associates the specific Handover activity withthe trunk.

12 The MSC tells the BSS to begin the Handover and provides the candidate cell frequency andHandover reference number.




4-110.1 Overview of the GSM Cellular System

Call Management

INTER-MSC HANDOVER

Basic -- Steps 1 & 2 (cont.)

BSS - Base Station SystemMS - Mobile StationMSC - Mobile Switching CenterMSHN - Mobile Station Handover Number



Overview of the GSM Cellular System 4-110.2

Call Management



4-110.3 Overview of the GSM Cellular System

Call Management

INTER-MSC HANDOVER


Perform HOAcknowledge

HO RequestAcknowledge

HandoverRequest

HandoverNumber

Allocated

4

SetupComplete

NetworkSetup

PerformHandover

AllocateHandoverNumber

3

2

HandoverCommand

HandoverRequired

...................................................................................................................

1

...................................................................................................................

.................................................................................................................

.................................................................................................................

.................................................................................................................

...................................................................................................................


MSCA

Um A MSCB

VLRB

BSSAMS BSS

B

12HandoverCommand

11

10

9

8

7

6

5




Call Management

INTER-MSC HANDOVER




15 The new BSS (B) notifies MSC B that the Handover has reached this point and MSC Bconnects the incoming trunk to the BSS trunk.

16 The mobile retunes to the traffic and associated signaling channel and sends a HandoverComplete to BSS B.

17 BSS B sends a Handover Complete message to MSC B.

18 MSC B sends a Send End Signal over the MAP network which signals MSC A to switch thepath from BSS A to the trunk to MSC B.

19 MSC B provides Answer indication for the inter-switch trunk on the trunk signaling system.

20 The MSC tells the old BSS (A) to release the radio channel and associated BSS to MSC trunk.

21 The old BSS (A) releases the radio channel and trunk and informs the MSC.





Call Management

INTER-MSC HANDOVER


Physical Chan.Information

HandoverDetected

HandoverComplete

Send EndSignal

Answer

HandoverComplete



13

14

15

16

17

18

19

20

21

BSSB

MSBSS

AMSC

B

AUm MSCA

HandoverAccess

......................................................................................................

....................................................................................................

....................................................................................................

......................................................................................................

......................................................................................................




Call Management

INTER-MSC HANDOVER

Basic -- After Call Ends

The opposite page diagram shows clearing of the resources after an inter-MSC Handover call ends

22 The anchor MSC (A) sends an END signal to the other MSC to signal the end of theMAP/TCAP transaction used to transmit the inter-MSC message during the time of the call.

23 The anchor MSC (A) also clears the voice trunk connection between the two MSCs using theappropriate trunk signaling type.

24 The MS Handover Number is released. In the 5ESS Switch implementation, the MSHN isactually released almost immediately after the inter-MSC trunk is setup in the initial stages ofthe Handover process. This frees up the number earlier and allows fewer numbers to beallocated for Handover purposes.





Call Management

INTER-MSC HANDOVER

Basic -- After Call Ends

......................................

MSCA

MSCB

VLRB

End Signal

Network Release

Release HandoverNumber

......................................

......................................

23

24

22




Call Management

INTER-MSC HANDOVER

Handback -- Steps 1 & 2

The opposite pages diagrams show an inter-MSC Handback. The situation is that an inter-MSCHandover has already occurred. A subsequent Handover back to MSC A is requested.



3 MSC B evaluates the candidates and chooses the best one. In this case, the best candidate is inanother MSC area. A MAP message is sent to MSC A (the Anchor MSC) requesting asubsequent Handover to a specified cell on MSC A.

4 A Handover Request message is sent to the new BSS with the candidate cell identified.


6 MSC A responds to MSC B with an acknowledgement of the Perform Subsequent Handoverand provides the information needed by the MSC (MSHN) and MS (frequency, Handoverreference number, etc.).

7 MSC B tells the BSS to begin the Handover and provides the candidate cell frequency andHandover reference number.






Call Management

INTER-MSC HANDOVER


...........................................................................................

............................................................................................


MSCB

Um A MSCA

BSSBMS BSS

A

PerformSubsequentHandover

3

HandoverRequest

HO RequestAcknowledge

SubsequentHandover

Acknowledge

HandoverCommand

HandoverCommand

4

5

7

8

6

2

HandoverRequired

............................................................................................

1

............................................................................................

...........................................................................................




Call Management

INTER-MSC HANDOVER




11 The new BSS (A) notifies MSC A that the Handover has reached this point.

12 The mobile retunes to the traffic and associated signaling channel and sends a HandoverComplete to BSS B.

13 The new BSS (A) sends a Handover Complete message to MSC A.

14 MSC A sends a End Signal over the MAP network which signals MSC A to release theprevious Handover connections.

15 MSC A releases the trunk between A and B.

16 The MSC tells the old BSS (B) to release the radio channel and associated BSS to MSC trunk.

17 The old BSS (B) releases the radio channel and trunk and informs the MSC.

18 Since the inter-MSC trunk has been released, the MSHN is no longer required and can bereleased for future use.





Call Management

INTER-MSC HANDOVER


End Signal

HandoverComplete

HandoverDetected

Physical Chan.Information

...............................................................................................................

...............................................................................................................

..............................................................................................................

..............................................................................................................

..............................................................................................................

...............................................................................................................

HandoverAccess

MSCB

Um A MSCA

VLRB

BSSBMS BSS

A

14

13

12

11

10

9

HandoverComplete

18

17Release

HandoverNumber

NetworkRelease

16

15






Call Management

INTER-MSC HANDOVER

3rd MSC -- Steps 1 & 2

The opposite pages diagrams show a subsequent inter-MSC Handover. The situation is that aninter-MSC Handover has already occurred. A subsequent Handover to a third MSC is requested.



3 MSC B evaluates the candidates and chooses the best one. In this case, the best candidate is inanother MSC area. A MAP message is sent to MSC A (the Anchor MSC) requesting asubsequent Handover to a specified cell on MSC C.

4 A MAP message is sent to MSC C requesting a Handover to a specified cell on MSC C.





Call Management

INTER-MSC HANDOVER

3rd MSC -- Steps 1 & 2

...........................................................

.........................................................

...........................................................

...........................................................

...........................................................

1

2

3

4

HandoverRequired


BSSB

MSCB

MSCC

MSCA

MS

PerformHandover

PerformSubsequentHandover




Call Management

INTER-MSC HANDOVER

3rd MSC -- Step 2 continued

5 Because Handover between switches will require voice trunks between the switches, aHandover Number (MSHN) is allocated for this handover. This is similar to the MSRNallocated for the termination of a mobile call. Number allocation is specified as a VLR entityoperation and the diagram shows a message flow between the MSC and VLR entities.

6 See item 4 above.

7 A Handover Request message is sent to the new BSS (C) with the candidate cell identified.


9 MSC C responds to MSC A with an acknowledgement of the Handover Perform and providesthe information needed by the MSC (MSHN) and MS (frequency, Handover referencenumber, etc.).

10 MSC A initiates the process to set up a voice path between MSC A and MSC C in order tosupport the path switching when the Handover occurs. MSC A sets up a call using the MSHNprovided above.

11 MSC C responds to the trunk set up attempt as appropriate for the trunk signaling used for thattrunk. In addition, MSC C notes the MSHN and associates the specific Handover activity withthe trunk.





Call Management

INTER-MSC HANDOVER


11

10

9

8


Setup Complete

Network Setup

Handover Request

.......................................................................................

.......................................................................................

6

7

5

.......................................................................................

......................................................................................

MSCA

MSCC

BSSC

VLRC

AllocateHandover Number

Handover NumberAllocated

Perform HandoverAcknowledge




Call Management

INTER-MSC HANDOVER


12 MSC A responds to MSC B with an acknowledgement of the Perform Subsequent Handoverand provides the information needed by the MSC (MSHN) and MS (frequency, Handoverreference number, etc.).

13 MSC B tells the BSS to begin the Handover and provides the candidate cell frequency andHandover reference number.






Call Management

INTER-MSC HANDOVER


SubsequentHandover

Acknowledge.........................................

.........................................

12

14

13

.........................................

.........................................

Handover Command

Handover Command

MSCA

MSCB

BSSBMS




Call Management

INTER-MSC HANDOVER

3rd MSC -- Step 3



17 The new BSS (C) notifies MSC C that the Handover has reached this point.

18 The mobile retunes to the traffic and associated signaling channel and sends a HandoverComplete to BSS C.

19 The new BSS (C) sends a Handover Complete message to MSC C.

20 MSC C sends a Send End Signal over the MAP network to MSC A.

21 MSC C sends Answer across the network trunk signaling system.





Call Management

INTER-MSC HANDOVER

3rd MSC -- Step 3

20

19

18Handover Complete

Handover Complete

Answer

Send EndSignal

Handover Detected

.......................................................................................

.......................................................................................

16

17

15

.......................................................................................

......................................................................................

MSBSS

CMSC

CMSC

A

Handover Access


21




Call Management

INTER-MSC HANDOVER

3rd MSC -- Step 4

22 MSC A sends a End Signal over the MAP network which signals MSC B to release theprevious Handover connections.

23 MSC A releases the trunk between A and B.

24 The MSC tells the old BSS (B) to release the radio channel and associated BSS to MSC trunk.

25 The old BSS (B) releases the radio channel and trunk and informs the MSC.

26 Since the inter-MSC trunk has been released, the MSHN is no longer required and can bereleased for future use.





Call Management

INTER-MSC HANDOVER

3rd MSC -- Step 4

26

Network Release

End Signal

VLRB

BSSB

MSCB

MSCA

......................................................................................

.......................................................................................

22

24

23

.......................................................................................

.......................................................................................


Release HandoverNumber


25




Call Management




Unit 5

5ESS MSC

Version 1.0.0April 27, 1993 -- 16:10:02 [unit05.x]


The Pan-European GSM Cellular System

5ESS MSC

UNIT OVERVIEW

Version 1.0.0June 28, 1991 -- 10:39:28 [djw.529]


5-2 The Pan-European GSM Cellular System

5ESS MSC

UNIT OVERVIEW

International 5ESS Architecture Overview

HLR, VLR, AUC, and EIR Implementation

Mobile to Land Call Scenario

Mobile Location Update Scenario

Inter-MSC Handover Scenario

.

Intra-MSC Handover Scenario

Land to Roaming Mobile Call Scenario

Version 1.0.0May 12, 1992 -- 13:53:03 [jjm.529]


The Pan-European GSM Cellular System 5-3

5ESS MSC

GSM REFERENCE MODEL

Version 1.0.0June 28, 1991 -- 11:32:21 [djw.428]



5ESS MSC

GSM REFERENCE MODEL

Abis

EIR

ISDN

PSTN

MSC

MSC

HLR



AUC

VLR

VLR

BSC

BTS

BSS

MS

F

E

C

A

B

G

D

Um

Version 1.0.0November 27, 1991 -- 14:17:56 [djw.428]



5ESS MSC

GSM REFERENCE MODEL

AT&T PRODUCT OFFERING

AT&T has developed the GSM system with the following three major GSM Network network elements. TheOperations Maintenance Center (OMC), Mobile Switching Center (MSC), and Base Station System (BSS).

The Home Location Register (HLR), Visitor Location Register (VLR), Authentication Center (AUC), andEquipment Identity Register (EIR) are being integrated within the MSC. As specified in the GSMrecommendations, it is not required that all network elements be implemented in different equipment.1

AT&T has also developed the B, C, D, E, F, and G interfaces for the HLR, VLR, AUC, EIR, and MSC tocommunicate within the 5ESS. These GSM interfaces allow the 5ESS to access HLR, AUC, and EIR datalocated on other entities in the GSM network for calls being processed on the 5ESS MSC product.Conversely, these interfaces also allow the 5ESS to function as a HLR, AUC, and EIR for mobile callsoriginated/terminated on other MSCs in the GSM network.

The network operator has the option of either integrating the MSC, HLR, AUC, VLR, and the EIR all thesame 5ESS product or having one 5ESS perform only as a MSC and having another 5ESS product act as astandalone HLR, AUC, EIR product. Thus, you can have all or part of the above network elements locatedon the 5ESS product or any combination there of.

Of all the databases, the VLR is most tightly coupled with the MSC and will probably never be moved off ofthe 5ESS. One possible advantage of moving the VLR off the 5ESS would be to increase call handlingcapacity of the MSC. As we will see shortly, the 5ESS has plenty of capacity.

There are several advantages associated with integrating all of the above listed network elements into theMSC and not formally implementing the interfaces between these entities as outlined in the GSMrecommendations. The primary advantages have to do with:

• Product Cost,

• Product Availability,

• System Capacity.

It is important that the price of initial GSM systems be as low as possible since Public Land Mobile Network(PLMN) providers will choose vendors based primarily on cost. Since all network elements need toimplemented on reliable fault tolerant equipment it makes sense to initially share the same hardwareequipment.


Version 1.0.0May 1, 1992 -- 14:56:08 [jc706.txt]



5ESS MSC

GSM REFERENCE MODEL

AT&T PRODUCT OFFERING

OMC

BSS

5ESSInternational

Switch

A

D

C

G

E

F

HLR

AUC

EIR

MSC

VLR

Up to 5 MSCs

PSTN

Version 1.0.0May 6, 1992 -- 15:57:28 [jc706.eps]



5ESS MSC




INTERNATIONAL 5ESSWIRELESS ARCHITECTURE OVERVIEW




5ESS MSC

SYSTEM ARCHITECTURE OVERVIEW

Version 1.0.0May 4, 1992 -- 13:54:31 [jjm.519]



5ESS MSC

SYSTEM ARCHITECTURE OVERVIEW

ISUP&

MAP

MAP

EIR

AUC

HLR

EIR

VLR

AUC

HLR

MSC

MSC

.......

CustomerAdministration

System

RS-232 OMC. . . . . . . . . . . . . . . . . . . . . . . ...

...

...

...

.. . . . . . . . . . . . . . . . . . . . . . . . ..............

X.25X.25

X.25

SS7

SS7mtce

& mtcecall proc

. . . . . . . . . . . . . . . ............ . . . . . . . . . . . . . . . ............

ExternalServiceCenter

countryspecific

signaling

PSTN

voice

. . . . . . . . . . . . . . ............ . . . . . . . . . . . . . . ............

BillingCenter

. . . . . . . . . . . ........... . . . . . . . . . . . ...........

MSBTS BSC

BSSAir

Interface

. . . . . .

Voice Path

SignalingPath

Version 1.0.0May 4, 1992 -- 14:17:33 [jjm.519]



5ESS MSC

BASIC 5ESS ARCHITECTURE

The following list identifies a few documents/books that provide overview information about the5ESS Switch.

• 5ESS Switch Global Description, 235-390-100, March 1989, Issue 1.

• 5ESS Training Program -- System Overview.

• 5ESS Training Program -- Advanced System Overview.

• 5ESS Switch Software, AT&T Technical Journal, January 1986.

Version 1.0.0April 27, 1992 -- 17:11:55 [corel783.txt]



5ESS MSC

BASIC 5ESS ARCHITECTURE

AM

SM SM GSM SM SM

CM

PSTN

Lines

Trunks

Signaling

5ESS InternationalSwitch

Version 1.0.0April 23, 1992 -- 16:52:21 [corel783.eps]



5ESS MSC

BASIC 5ESS WIRELESS SWITCH ARCHITECTURE

• AT&T is using the 5ESS International Switch as the Mobile Switching Center (MSC) forcellular service based on the GSM standard.

• The term "5ESS wireless switch" is commonly used instead of MSC or 5ESS MSC.

• No new hardware is required to be developed on the 5ESS in order to support GSM cellularservices.

• Switching Modules (SMs) are the main building blocks of the 5ESS MSC, which performsover 95% of all the call processing.

• A new Switching Module term, Wireless Switching Module (WSM) is used to descibe aswitching module that is capable of providing wireless services. The hardware architecture ofa WSM is basically the same as regular SMs when equipped with trunks.

• Maximum capacity: 300k subscribers or 500k Busy Hour Call Attempts (BHCA).

AM - Administrative ModuleBSS - Base Station SystemCM - Communications ModuleMSC - Mobile Switching CenterNCT - Network Control TimeslotPSTN - Public Switched Telephone NetworkSM - Switch ModuleWSM - Wireless Switch Module

Version 1.0.0March 1, 1992 -- 21:39:40 [djw.400]



5ESS MSC

BASIC 5ESS WIRELESS SWITCH ARCHITECTURE

AM

WSM WGSM WSM GSM SM

CM

Lines

Trunks

Trunks

SignalingSignaling

BSSBSS

5ESS Switch

MSC

PSTN &Other PLMN Entities




5ESS MSC

32 CHANNEL DIGITAL FACILITIESUSED BETWEEN MSC AND BSSs

The type of facilities used to connect Base Station Systems (BSSs) to the the Mobile SwitchingCenter (MSC) are CCITT 2048 kbps (32 channel) digital facilities.2 The following list providesadditional details concerning these facilities:

• Each facility consists of 32 64 kbps channels (or timeslots)3

• 30 timeslots are available for voice and/or data connections (slots 1 - 15 and 17 - 31).

• Voice signals are digitally encoded using Pulse Code Modulation (PCM)4

• Timeslot 16 is recommended for common channel signaling. Timeslot 16 can also be use forregular voice/data connections. If desired, a timeslot other than slot 16 can be used to transfersignaling messages (e.g., timeslot 18).

• Timeslot 0 is used for synchronization/timing

• 8 bits per timeslot

• 256 bits per frame

As state above, timeslot 16 is recommended for common channel signaling. On the 5ESS, any ofthe 31 timeslots (1 - 31) can be used as a signaling channel. It appears that the AT&T BSS productcannot use timeslot 16 for common channel signaling.

If there are more than one 32 channel digital facilities between the 5ESS and one BSS, then it is notnecessary for all facilities to have a signaling link. For the facilities that are not engineered to carrya signaling link, timeslot 16 can be use for voice/data connections. More information regardingBSS signaling links is provided on Page 5-26.

2 . See GSM Recommendation 08.04, "Mobile Switching Center (MSC) to Base Station System (BSS)Interface; Layer 1: Structure of Physical Circuits"

3 . For more details, see CCITT Recommendation G.704.4 . For more details, see CCITT Recommendation G.711 and G.732.




5ESS MSC

32 CHANNEL DIGITAL FACILITIESUSED BETWEEN MSC AND BSSs

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

SYNC

VOICE AND/OR DATASI

GVOICE AND/OR DATA

Message Transport Part - Layer 1Message Transport Part - Layer 2

Message Transport Part - Layer 3

Signaling Connect Control Part

BSS ManagementApplication Part

Direct TransferApplication Part

BSS Operationsand MaintenanceApplication Part

GSM ‘A’ INTERFACESIGNALING PROTOCOL STACK

ONE FRAME




5ESS MSC

MAXIMUM DIGITAL FACILITIES PER WSM




5ESS MSC

MAXIMUM DIGITAL FACILITIES PER WSM

CommunicationsModule (CM)

01

2

511

0

Two NCT Links(256 slots each)

Time SlotIntechanger (TSI)

Digital Line Trunk Unit

32 channel digital facilities(2.048 Mbps)

Maximum of 16 Digital Trunk Facilities

(maximum number of timeslots = 480)

WSM




5ESS MSC

WSM TRUNK ENGINEERING

• Maximum number of simultaneous calls per WSM = 480 (assuming it is fully engineered withtrunks).

• Maximum number of simultaneous calls per BSS = 320 (assuming it is full equipped withradios).

Version 1.0.0April 23, 1992 -- 16:36:47 [djw.633]



5ESS MSC

WSM TRUNK Engineering

BSS1

WSM2

BSS2

WSM3

WSM4

BSS16

BSS17

DFIMaximum*BSSs per

WSM = 16

DFIMaximum*WSMs perBSS = 11

WSM1

5ESS MSC

* AT&T DACs products allow you to exceed these maximums




5ESS MSC

5ESS WSM ARCHITECTURE

Version 1.0.0June 28, 1991 -- 10:43:03 [djw.607]



5ESS MSC

5ESS WSM ARCHITECTURE

16 DFI Maximum

512 Time Slots to theCommunications Module (CM)

Digital Line Trunk Unit(DLTU)

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...............................

DFIDFIDFIDigital FacilityInterface (DFI)

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ................. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .................

Packet SwitchingUnit (PSU)

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ................. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .................

Time SlotInterchange Unit

(TSIU)

Switch ModuleProcessor (SMP)

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ................. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .................

Wireless Switch Module (WSM)

32 Channel Digital Trunks(2.048 Mbps)

Version 1.0.0May 4, 1992 -- 14:19:21 [jjm.607]



5ESS MSC

WIRELESS GLOBAL SM (WGSM)

Logical Signaling Path View

One Wireless Switching Module (WSM) in the 5ESS has the global responsibility of distributingsignaling messages between Base Station Systems (BSSs) and WSMs, and hence termed theWireless Global Switching Module (WGSM).

As illustrated on the following page, all signaling links from BSSs ultimately terminate on theWGSM. The number of signaling links per BSS can be engineered between two and four (twolinks should be more than adequate to handle most traffic situations).

Since trunks and call handling responsibilities between the 5ESS and a given BSS are distributedacross multiple WSMs, it is necessary to have a signaling message switch (the WGSM). TheWGSM hides internal 5ESS distributed processor/processing architectural details from BSSs, thusproviding the appearance to all BSSs that the MSC is logically one entity.

The WGSM provides the capability for any WSM to send messages to any BSS, and vice versa(even if there are no physical facilities between a given BSS and WSM). Later in this unit, youwill be introduced with conditions whereby messages sent from a BSS to the MSC can be deliveredto a WSM that does not have physical facilities to the BSS.

The diagram on the following page shows trunks from BSSs terminating on WSMs and thesignaling links terminating on the WGSM. This is a LOGICAL VIEW. Physically, the signalingand voice paths are time-division-multiplexed on 32 channel digital facilities.

The "dotted" paths between the WGSM and WSMs are message delivery paths. Message deliverypaths (often referred to as MD paths) are nailed up 64k BPS time slots between the WGSM andWSMs for the purpose of delivering signaling messages the correct WSM. Currently, each WSMhas one MD path to the WGSM. If a 5ESS is equipped, for example, with 10 WSMs, then theWGSM would have 10 MD paths; one to each of the WSMs.

The maximum number of WGSMs that be equipped in a 5ESS is one. Early architectural studiesdetermined that one WGSM would have adequate capacity for switching signaling messages at themaximum advertized call handling load.




5ESS MSC


Logical Signaling Path View

CM

WSM2

BSS2

WSM1

BSS1

WGSM3

VoiceTrunks

64k BPSNailed upTimeslots

5ESS MSC

2 - 4 64k BPSSS7 Signaling Links

Legend

Voice Path

SS7 Signaling PathMessage Delivery Path

Version 1.0.0February 10, 1992 -- 23:08:56 [corel720.eps]



5ESS MSC

EXAMPLE: FACILITIES BETWEEN 5ESS AND 1 BSS

Illustrated is one Base Station System (BSS) equipped with seven 32 channel facilities whichterminates on 4 WSMs. Paths identified with the letter "A" represent facilities that also have acommon channel signaling link. Two of the 7 facilities carry the signaling links to BSS 1--whichshould have more than enough bandwidth to meet maximum call load situations.5 For reliabilityreasons, it is unwise to place both signaling links on the same facility.

Notice that the "B" paths have timeslot 16 available for voice/data connections. The total numberof voice/data circuits (trunks) between the 5ESS and BSS 1, in this example, is 215. From atrunk-management standpoint, all 215 trunks are grouped into one "trunk group." If the 5ESS wasto receive a call origination message over one of the signaling links from BSS 1, the AdministrativeModule (AM) would eventually be asked to find an available trunk (out of the 215 member trunkgroup) serving BSS 1.

5 .This example shows facilities with both signaling channels using timeslot 16, per the CCITTrecommendations. It is not a requirement that signaling be performed in timeslot 16--other timeslotssuch as 18 could be used. For hardware reasons, the AT&T Base Station Controller may not be able touse timeslot 16 for signaling.




5ESS MSC

EXAMPLE: FACILITIES BETWEEN 5ESS AND 1 BSS

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

SYNC

VOICE AND/OR DATA VOICE AND/OR DATA

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

SYNC

VOICE AND/OR DATASI

GVOICE AND/OR DATA

BSS1

WSM2

WSM3

WSM4

WSM1

5ESS MSC

A

B

AA B B B BB




5ESS MSC


Actual Signaling Path View

Version 1.0.0June 28, 1991 -- 10:43:47 [djw.528]



5ESS MSC


Actual Signaling Path View

CM

WSM2

BSS2

WSM1

BSS1

WGSM3

VoiceTrunks

64k BPSNailed upTimeslots

5ESS MSC

2 - 4 64k BPSSS7 Signaling Links

Legend

Voice Path

SS7 Signaling PathMessage Delivery Path

Version 1.0.0May 21, 1992 -- 17:14:05 [corel721.eps]



5ESS MSC

BSS-5ESS SIGNALING ARCHITECTURE

Version 1.0.0June 28, 1991 -- 10:44:00 [djw.487]



5ESS MSC

BSS-5ESS SIGNALING ARCHITECTURE

MDPH

MDPH MD

PH

STPH

STPH

STPH

MDPH

SMP SMP

WSM1

WSM2

WGSM3

OMC

BSS1

BSS2

CM5ESS MSC




5ESS MSC


Version 1.0.0June 28, 1991 -- 10:44:00 [djw.487]



5ESS MSC


MSUm

BTSA-bis

BSCA

MSC

Um

A

A-bis

Phys.

LAPDm

RRRR’

LAPDm

Phys.

BTSMLAPD

Phys. Phys.

LAPD

BTSM

RR’’

MTP

SCCP

BSSMAP

BSSMAP

SCCP

MTP

MM

CMCM

MM




5ESS MSC

PSTN & PLMN-5ESS SIGNALING ARCHITECTURE

Version 1.0.0June 28, 1991 -- 10:44:16 [djw.488]



5ESS MSC

PSTN & PLMN-5ESS SIGNALING ARCHITECTURE

MDPH

MDPH MD

PH

STPH

STPH

STPH

MDPH

SMP SMP

SM4

SM5

GSM6

CM5ESS MSC

PSTN &Other PLMN Entities




5ESS MSC

MAP SIGNAL PROTOCOL STACK ARCHITECTURE

Version 1.0.0June 28, 1991 -- 10:44:16 [djw.488]



5ESS MSC

MAP SIGNAL PROTOCOL STACK ARCHITECTURE

C,D,E,F,G

C,D,E,F,G

SCCP-CLSCCP-CL

MTP-1MTP-1

TCAPTCAP

MAPMAP

MTP-3MTP-3

MTP-2MTP-2

SCCP-CLSCCP-CL

MTP-1MTP-1

TCAPTCAP

MAPMAP

MTP-3MTP-3

MTP-2MTP-2

MSC,HLR,EIR

MSC,HLR,EIR




5ESS MSC

PACKET SWITCH UNIT SIGNAL LINK ARCHITECTURE

Version 1.0.0June 28, 1991 -- 10:44:16 [djw.488]



5ESS MSC

PACKET SWITCH UNIT SIGNAL LINK ARCHITECTURE

SM

TSIU

DFIDLTU

SM

CM

TMS

AM

TSIU

DFIDLTU

GSM

TSIU

DFIDLTU

PSU

ST-PH MD-PH ST-PH MD-PH

DF

PF

PI

CF

PSU

MD-PH

DF

PF

CF

SMP

SSignalingDData Link




5ESS MSC

GSM TERMINOLOGY




5ESS MSC

GSM TERMINOLOGY

• GSM -- Group Special Mobile

• GSM -- Global System for Mobilecommunication

• GSM -- Global Switching Module

Version 1.0.0December 6, 1991 -- 16:29:14 [djw.681]



5ESS MSC

INTER-SM MESSAGE COMMUNICATION

Version 1.0.0June 28, 1991 -- 10:44:32 [djw.533]



5ESS MSC

INTER-SM MESSAGE COMMUNICATION

CM

WSM1

WSM2

WSM3

GSM5

SM6

SM7

WGSM4

2Control

TimeSlots(CTS)

48k BPSeach

5ESS MSC




5ESS MSC

SUMMARY OF 5ESS MESSAGESWITCHING ARCHITECTURE

Version 1.0.0November 25, 1991 -- 10:20:18 [corel717.txt]



5ESS MSC

SUMMARY OF 5ESS MESSAGESWITCHING ARCHITECTURE

CM

WSM1

WSM2

GSM4

SM5

SM6

WGSM3

BSS1

BSS3

BSS2

PSTNPLMN

64k BPSSS7

Links

2 48k BPSControl

Time Slots(CTS)

64k BPSMessageDelivery

Link

5ESS MSC




5ESS MSC

EXTERNAL DATABASE ACCESS

High Level View

Version 1.0.0May 11, 1992 -- 07:47:40 [db.1]



5ESS MSC

EXTERNAL DATABASE ACCESS

High Level View

SS7SDL

Application DataBase

GSM GSM

WSM WSM

5ESS Switch MSC 5ESS Switch Data Base

Version 1.0.0June 1, 1992 -- 12:11:19 [ccl_c001.eps]



5ESS MSC

WIRELESS DATABASE ACCESS

Example

Version 1.0.0May 11, 1992 -- 07:47:44 [db.2]



5ESS MSC


Example

CallProcessing

MDPH

SMP

WSM

GSM GSM

WSM

5ESS Switch Data Base5ESS Switch MSC

MDPH

MDPH

STPH

STPH

SS7SDL

MDPH

MDPH

STPH

STPH

SMP

MDPH

HLR




5ESS MSC


MAP Message Routing

Version 1.0.0May 11, 1992 -- 07:47:49 [db.3]



5ESS MSC


MAP Message Routing

MAPUser

MAPUser

MAP

MAP

TCAP

TCAP

SMP

SMP

PSU

PSU

PSU

PSU

MDPH

MDPH

MessageDelivery

MessageDelivery

MessageDelivery

SMP

SMP

SCCP

SCCP

MTP

MTP

MDPH

MDPH

STPH

STPH

GSM

GSM

WSM

WSM

5ESS Switch

5ESS Switch

Distribution




5ESS MSC




HLR, VLR, AUC, and EIRIMPLEMENTATION




5ESS MSC

AT&T GSM HLR, VLR, AUC, & EIR

Version 1.0.0June 28, 1991 -- 10:44:56 [djw.520]



5ESS MSC

AT&T GSM HLR, VLR, AUC, & EIR

• Maximum HLR Size = 300k subscribers

• Maximum VLR Size = 300k registeredsubscribers

• Up to 15,000 per WSM

Version 1.0.0May 4, 1992 -- 14:23:50 [jjm.520]



5ESS MSC

IMPLEMENTATION OF HLR & VLR ON 5ESS

Version 1.0.0June 28, 1991 -- 10:45:48 [djw.523]



5ESS MSC

IMPLEMENTATION OF HLR & VLR ON 5ESS

2N+1

HLR&

VLR

2N

WSM 2

N+1

HLR&

VLR

N

WSM 1

0

HLR&

VLR

N = up to 15,000

3N

WSM 3

Version 1.0.0May 4, 1992 -- 14:44:01 [jjm.523]



5ESS MSC

ROUTING SERVICE REQUESTS

TO THE CORRECT VLR

Version 1.0.0June 28, 1991 -- 10:46:01 [djw.492]



5ESS MSC

ROUTING SERVICE REQUESTS

TO THE CORRECT VLR

VLR VLR VLR

WSM 1 WSM 2 WSM 3

MD-PH

ST-PH ST-PH

MD-PH MD-PH

WGSM

BSS 1 BSS 2

5ESSMSC

Version 1.0.0December 11, 1991 -- 16:37:56 [corel722.eps]



5ESS MSC

TMSI ORGANIZATION

• The maximum number of Switching Modules (SMs) that can presently be supported withinone 5ESS is 190. The eight bit WSM field with in the TMSI supports the maximum numberof SMs.

• Since the maximum number of VLR records per WSM is 15,000, 16 bits is required to supportthis range.

• The 8 bit random number field of the TMSI can result in 256 different combinations of TMSIvalues for a given VLR entry.

Version 1.0.0June 5, 1992 -- 16:42:59 [djw.467]



5ESS MSC

TMSI ORGANIZATION

WSMNumber

VLRIndex

RandomNumber

0

8 bits 16 bits 8 bits

10 11 23 24 31

Version 1.0.0May 8, 1992 -- 15:33:35 [djw.467]



5ESS MSC

LOCATION OF AUTHENTICATION CENTER




5ESS MSC

LOCATION OF AUTHENTICATION CENTER

WSM 2

WGSM

SMP

MD-PH

AUCHLR/VLR

WSM 1

SMP

MD-PH

AUC

A3 & A8Algorithms

A3 & A8Algorithms

HLR/VLR

Message Delivery Links

Version 1.0.0May 22, 1991 -- 13:58:40 [djw.524]



5ESS MSC

LOCATION OF EQUIPMENT IDENTITY REGISTER

Version 1.0.0July 2, 1991 -- 12:49:28 [djw.525]



5ESS MSC

LOCATION OF EQUIPMENT IDENTITY REGISTER

M = up to 3200

2M+1

2M

M+1

M

0

EIR

HLR/VLR

WSM 2

EIR

HLR/VLR

WSM 1

EIR

HLR/VLR

WSM 3

3M

Version 1.0.0May 4, 1992 -- 15:30:09 [jjm.525]



5ESS MSC

Version 1.0.0May 4, 1992 -- 15:30:09 [jjm.525]



ROAMING MOBILE REGISTRATION SCENARIO




5ESS MSC

ROAMING MOBILE REGISTRATION

Version 1.0.0May 11, 1992 -- 07:38:55 [lu.1.1]



5ESS MSC



(LAI = MCC-06-20)

Need IMSI(TMSI = 7777)

Update Location(IMSI = MCC-02-1234567)

(VLR Adr = Taichung)

Insert Subscriber Data(Subscriber data)

IMSI Response(IMSI = MCC-02-1234567)(Authentication vectors)

1

IMSI = MCC-02-1234567TMSI = 7777

IMSI = MCC-02-1234567

IMSI = MCC-02-1234567MSISDN = 886-2-741-0051

TAINAN

TAICHUNG

TAIPEI

VLR

VLR

HLR

Subscriber DataVLR Adr = Tainan

BSS3

BSS8

LAI = MCC-06-20

LAI = MCC-03-68

BSS4

BSS5

Subscriber DataLA = 20

2

4 5

3

Network 6

Network 2

Network 3




5ESS MSC

ROAMING MOBILE REGISTRATION - Cont

Version 1.0.0May 11, 1992 -- 07:38:55 [lu.1.1]



5ESS MSC

ROAMING MOBILE REGISTRATION - Cont


(LAI =MCC-03-68)

Update Complete Subscriber Data Inserted

Delete Record(IMSI = MCC-02-1234567)

10

9

IMSI = MCC-02-1234567TMSI = 7777

IMSI = MCC-02-1234567TMSI = 8888

VLR

VLR

HLR

BSS3

BSS8

BSS4

BSS5

Subscriber Data

Subscriber Data

LA = 20

LA = 68

6

7 6

8

IMSI = MCC-02-1234567MSISDN = 886-2-741-0051

TAINAN

TAICHUNG

TAIPEI

Subscriber DataVLR Adr = Taichung

LAI = MCC-06-20

LAI = MCC-03-68

Network 6

Network 2

Network 3Version 1.0.0



5ESS MSC


Request for Service and IMSI Query

Version 1.0.0May 11, 1992 -- 07:38:55 [lu.1.1]



5ESS MSC


Request for Service and IMSI Query

Location UpdateRequest (TMSI)

Send IMSI

VLRWSM

SelectedWSM

MAPVLR SM

Location UpdateRequest (TMSI)


....................................................................................

.....................................................................................

....................................................................................

....................................................................................

IMSI Result

Taichung MSC

BSSMS

Tainan MSC

Channel Request

Create VLR

....................................................................................

Version 1.0.0May 11, 1992 -- 19:31:29 [lu.1.1]



5ESS MSC


Auth., Create New & Cancel Old VLR

Version 1.0.0May 11, 1992 -- 07:44:52 [lu.1.2]



5ESS MSC


Auth., Create New & Cancel Old VLR

.....................................................................................

Taipei MSC

VLRWSM

MAPMAPHLR SM

Tainan MSC

Insert Subscriber Data

Location UpdateAccepted

Update Location

Subscriber Data Inserted

.....................................................................................

VLRWSM

Cancel VLR

Cancel VLRAcknowledge

.....................................................................................

.....................................................................................

....................................................................................

Taichung MSC

MS

Authentication Response

Authentication Request

Version 1.0.0May 11, 1992 -- 19:32:11 [lu.1.2]



5ESS MSC


TMSI Reallocation, LU Complete

Version 1.0.0May 11, 1992 -- 07:45:02 [lu.1.3]



5ESS MSC


TMSI Reallocation, LU Complete

MS

Cipher Mode Complete

Cipher Mode Set

Cipher Mode Command

Set Cipher Mode

Location Update Complete

Location Update Accept

.....................................................................................

VLRWSM

Clear Complete

Release RadioSignaling Channel

Clear SignalingConnection

.....................................................................................

....................................................................................

Taichung MSC

BSS

Version 1.0.0May 11, 1992 -- 19:32:41 [lu.1.3]



5ESS MSC

Version 1.0.0May 11, 1992 -- 19:32:41 [lu.1.3]



MOBILE TO LAND CALL SCENARIO




5ESS MSC

VLR SM & TRUNK SM RELATIONSHIP

Version 1.0.0June 28, 1991 -- 10:46:47 [djw.493]



5ESS MSC

VLR SM & TRUNK SM RELATIONSHIP

VLR

WSM 1 WSM 2

ST-PH

MD-PHMD-PH

WGSM

BSS 1

5ESSMSC

TrunksSignaling

Data links

CallControl

TRUNK WSM VLR WSM

MessageDelivery

Links




5ESS MSC

SMs USED FOR A MOBILE TO LAND CALL

Version 1.0.0June 28, 1991 -- 10:46:59 [djw.404]



5ESS MSC

SMs USED FOR A MOBILE TO LAND CALL

- Base Station System- Global Switching Module- Public Telephone Switched Network- Switching Module- Visitor Location Register WSM- Wireless Global Switching Module- Wireless Switching Module

Voice Path

Signalling Path

BSSGSMPSTNSMVLR WSMWGSMWSM

.

VLRWSM

GSM

PSTN

WGSM WSMSM

BSS

Version 1.0.0May 22, 1991 -- 14:44:02 [djw.404]



5ESS MSC


Version 1.0.0June 28, 1991 -- 10:47:13 [djw.304]



5ESS MSC




• Ciphering∗


• Call Setup

• Handover(s)∗

• Release


Version 1.0.0May 22, 1991 -- 14:46:42 [djw.304]



5ESS MSC

MOBILE TO LAND CALL

Request for Service

The following is an example of an interprocessor message scenario for a mobile-to-land call. It isassumed that the mobile station is already registered with the system and has been allocated aTemporary Mobile Identification Number (TMSI).

0 A mobile originated call starts by the user entering the directory number digits, associatedwith the person to be called, on the mobile station handset. The user presses the "send" keyafter all digits have been entered.

1 Mobile station transmits a channel request message over a common access channel, RandomAccess Channel (RACH). The access scheme for this channel is similar in concept to slottedALOHA. Although unlikely, it is possible that the mobile will have to retry this messageseveral times.


3 The mobile station transmits a service request message to the base station over the SDCCH.Included in this message is the mobile station TMSI and Location Area Identification (LAI).This message also establishes a layer 2 signaling connection between the mobile station andthe base station.

4 The base station forwards the service request message to the MSC, which is first received bythe WGSM.

5 The Protocol Handler (PH) in the WGSM that receives the Service Request message will usethe high-order bits of the TMSI to determine which WSM contains the VLR data for themobile subscriber and forward the service request to the appropriate WSM. The WSMcontaining the VLR record for a given mobile subscriber is referred to as the "VLR WSM."Included in this message to the VLR WSM is the BSS number currently serving the mobilestation.

Version 1.0.0July 12, 1991 -- 15:37:37 [djw.622]



5ESS MSC

MOBILE TO LAND CALL

Request for Service

5

4

3

Service Request

Service Request


.......................................................................

......................................................................

MS BSS WGSMVLRWSM

Channel Request

.......................................................................

.......................................................................

1

Um A

Service Request

2

Version 1.0.0July 5, 1991 -- 10:33:34 [djw.622]



5ESS MSC

MOBILE TO LAND CALL

Authentication and Call Setup

Since the air interface is vulnerable to fraudulent access, it is necessary to determine if the TMSIreceived from the mobile station is from the SIM that the TMSI was assigned.

6 Since the functionality of the HLR, VLR, and the AUC have been integrated in to the VLRWSM, this step performs many operations that do not result in interprocessor messages. Toauthenticate the mobile station, the VLR WSM needs to generate, or retrieve previouslygenerated, authentication parameters: Random number (RAND), Signed Response (SRES),and the Cipher Key (Kc). If no authentication parameters exist, the VLR WSM will send amessage to its MD-PH (Message Delivery Protocol Handler) requesting it to execute theAuthentication Algorithm (A3) and Cipher Key Algorithm (A8) for a given IMSI andAuthentication Key (Ki), and return 5 authentication parameter triplets. One of the tripletswould be used for this call. The remaining 4 triplets would be available for future calls. TheMD-PH should only receive requests one out of every five times that authentication isnecessary. The VLR WSM then sends the random number, RAND, to the mobile stationrequesting it to apply the random number to its A3 and A8 algorithm.

7 In parallel with mobile station authentication, the VLR WSM sends a request message to theAdministrative Module (AM) to allocate a trunk to the BSS currently serving the mobilestation.

8 The AM allocates a BSS trunk and sends a message to the WSM that manages this trunk.This WSM is referred to as the Trunk WSM. It is possible that the trunk WSM selected is thesame as the VLR WSM. Presently, the AM does not bias its BSS trunk hunt to favor thetrunks on the VLR WSM.

9 The mobile station reads its Authentication key (Ki) from the SIM, applies the randomnumber, RAND, and Ki to both its Authentication Algorithm (A3) and Cipher key generationalgorithm (A8) to produce an authentication Signed Response (SRES) and Cipher Key (Kc).The mobile station saves Kc for later, and will use Kc when it receives a command to cipherthe channel. The mobile station then returns the generated SRES to the MSC (VLR WSM).The VLR WSM compares the SRES returned from the mobile station with the expected SRESgenerated earlier from the AUC entity in the VLR WSM. If equal, the mobile station passesauthentication. If unequal, appropriate actions will be taken--which could result in the SIMbeing disabled. In this scenario, we’ll assume that authentication passes.

10 The Trunk WSM then informs the VLR WSM that it has been selected as the Trunk WSM andthat a BSS trunk has been reserved.

Note: it is not known what the exact timing relationship will be between the mobile stationauthentication response and the assignment of a BSS trunk from the AM. It is not important thatthis be known since the VLR WSM will not proceed with the call until both the authenticationresponse and a report is received from the trunk WSM.

Version 1.0.0July 5, 1991 -- 10:25:49 [djw.623]



5ESS MSC

MOBILE TO LAND CALL

Authentication and Call Setup

10

9

8

6


.......................................................................

......................................................................

MSVLRWSM

TrunkWSM AM

Authenticate Mobile

.......................................................................

.......................................................................

Assign TrunkWSM & BSS Trunk

Request BSSTrunk

Trunk WSM &BSS Trunk Selected

7

Version 1.0.0July 5, 1991 -- 10:35:32 [djw.623]



5ESS MSC

MOBILE TO LAND CALL

Ciphering and Call Setup

11 The VLR WSM then transfers a copy of the subscriber VLR record to the trunk WSM.

12 Using the Cipher Key (Kc) that was generated earlier during authentication, the VLR WSMconstructs a cipher command and sends it to the BSS, via the WGSM. The VLR WSMincludes in this message the Trunk WSM identification.

13 The WGSM receives the cipher command message, extracts and saves the Trunk WSMidentification, and forwards this command to the BSS. The WGSM uses the Trunk WSMidentification to begin routing most messages from the BSS directly to the Trunk WSMinstead of the VLR WSM.



16 The BSS upon receiving the cipher mode complete message starts ciphering the downlinkchannel, and then sends a cipher complete message to the MSC. The WGSM forwards thecipher mode complete message to the VLR WSM.

17 The mobile station upon receiving the cipher command stimulus transmits to the MSC a callsetup message. Included in this message are the dialed digits. Note: the mobile station waitsuntil the channel is ciphered before transmitting the dialed digits. If the MSC elects to skipciphering the channel, then the MSC must send the mobile station a message indicating thatciphering will not be performed and that the mobile should send a call setup message.

18 The WGSM, upon receiving this message, routes the call setup message to the trunk WSM.This is the first message trunk WSM has received from the mobile station.

19 The trunk WSM analyzes the dialed digits, checks its local copy of the mobile station VLRrecord and determines that the call can proceed. One example on where a call might be deniedif the mobile station is restricted from dialing certain directory numbers, such as internationalcalls. Again, assuming that the call can proceed, the trunk WSM sends a call proceedingmessage to the mobile station.

Version 1.0.0July 5, 1991 -- 10:26:55 [djw.624]



5ESS MSC

MOBILE TO LAND CALL

Ciphering and Call Setup

19

Call SetupRequest

18

Call SetupRequest

17

Cipher Complete16

Cipher ModeComplete

Cipher ModeCommand

15

14

13 Cipher Command

Cipher Command+ WGSM Routing

Information12

Transfer copyof VLR record11

.........................................................................................................

.........................................................................................................

.........................................................................................................

.......................................................................................................

Um A

BSSMS VLRWSM

TrunkWSMWGSM

.......................................................................................................Call Proceeding

Version 1.0.0July 5, 1991 -- 10:37:05 [djw.624]



5ESS MSC

MOBILE TO LAND CALL

Equipment Validation and Call Setup

The purpose of the equipment validation phase is to read the mobile equipment serial number fromthe mobile station and check it against the Equipment Identity Register (EIR) to determine ifspecial action should be taken, such as deny service. Equipment validation is optional and iscontrolled by the service provider. Equipment validation is performed after the ciphering phaseand in parallel with call setup.

20 The VLR WSM transmits a request to the mobile station requesting it to respond with itsInternational Mobile Equipment Identity (IMEI).

21 The trunk WSM and VLR WSM are operating in parallel at this point in time. The lastactivity performed by the trunk WSM was to analyze the call setup message received fromthe mobile station, followed by sending the mobile station a call proceedingacknowledgment. The next task for the trunk WSM is to send a message to the Base StationSystem (BSS) requesting it to allocate a radio traffic channel and connect the radio to aterrestrial trunk to the MSC. Included in the message is the terrestrial circuit identity code(trunk number).

22 The mobile station, upon receiving the IMEI request, returns the IMEI back, over theencrypted radio path, to the VLR WSM. The VLR WSM then requests the MS’s IMEIinformation from the EIR by sending a message to the PSTN GSM MDPH. The MDPH thendetermines whether the EIR is located on the MSC or on another network entity. It retrievesthe EIR information on the MSC, if the MSC contains the EIR, or sends a MAP message tothe EIR off the MSC. Once the MDPH receives the EIR data, it then sends it back to theVLR WSM for checking.

23 The VLR WSM uses the received IMEI a key into the Equipment Identity Register (EIR) todetermine that status of the mobile equipment, and forwards both the IMEI and status to thetrunk WSM. If the results are good, the trunk WSM will allow the call to proceed. If theEIR results are negative, the trunk WSM will begin to terminate the call.

24 The BSS reserves a radio traffic channel, connects the radio to the specified MSC trunk, andsends a radio traffic channel assignment message to the mobile station (over the Stand-aloneDedicated Control Channel (SDCCH)).

25 The mobile station tunes to the specified traffic channel and transmits an assignmentcomplete message back to the BSS. The mobile station then begins alerting the user (i.e., thephone rings). Prior to this point in time, the mobile station user is unaware that he/she isreceiving al call. The mobile station no longer uses the SDCCH after tuning to thedesignated radio traffic channel.

26 The BSS upon receiving the assignment complete message, places the SDCCH on a free listand transmits an assignment complete message to the trunk WSM.

Version 1.0.0May 5, 1992 -- 16:22:03 [jjm.625]



5ESS MSC

MOBILE TO LAND CALL

Equipment Validation and Call Setup

FPSTNGSM

TrunkWSMMS

Um

BSS

21

22

26

25

24

23

20

EIR

............................................................................................................

............................................................................................................

Request IMEI

IMEI CheckResults

Trunk & RadioChannel Assignment

Complete

Assign RadioTraffic Channel

Trunk Assignment &Request Radio Traffic

Channel Allocation

IMEI Response

..............................................................................................................

Channel AssignmentComplete

............................................................................................................

............................................................................................................

............................................................................................................

Request IMEI from EIR

Request IMEI

Return IMEI

IMEI Response

VLRWSM

A

Version 1.0.0May 12, 1992 -- 13:58:49 [jjm.625]



5ESS MSC

MOBILE TO LAND CALL

Call Setup

27 AM finds an available trunk in the specified trunk group and reserves an inter-SM networktimeslot.

28

29

30

31

32

33

34

35

36

37




5ESS MSC

MOBILE TO LAND CALL

Call Setup

37

36

Alerting33

Network Alerting32

Network Alerting31

Network Setup30

SM & PSTNtrunk selected

Assign PSTNTrunk

29

28

MS SM PSTNAMTrunkWSM

AllocatePSTN Trunk27

.........................................................................................................

.........................................................................................................

.........................................................................................................

.......................................................................................................

.......................................................................................................

34

Answer

Answer

35ConnectionEstablished

ConnectionAcknowledgment

Version 1.0.0July 5, 1991 -- 10:40:13 [djw.626]



5ESS MSC

MOBILE TO LAND CALL

Mobile Release

Version 1.0.0June 28, 1991 -- 10:48:23 [djw.627]



5ESS MSC

MOBILE TO LAND CALL

Mobile Release

45 Billing Record

Release BSSTrunk

44

Release PSTNTrunk43

Network Release42

Network Release41

Mobile Release

Mobile ReleaseComplete40

39

MS SM PSTNAMTrunkWSM

MobileDisconnect38

...............................................................................................

...............................................................................................

...............................................................................................

..............................................................................................

..............................................................................................

Version 1.0.0July 5, 1991 -- 10:41:32 [djw.627]



5ESS MSC

MOBILE TO LAND CALL

Mobile Release (cont.)

Version 1.0.0June 28, 1991 -- 10:48:36 [djw.628]



5ESS MSC

MOBILE TO LAND CALL

Mobile Release (cont.)

51

...........................................................................

...........................................................................

............................................................................

............................................................................

............................................................................

46Connection

Release

BSS WGSM TrunkWSM

VLRWSM

MS

47

48 Clear Command

Clear Command

49 Channel Release

A Um

50 Clear Complete

Clear Complete

Version 1.0.0July 5, 1991 -- 10:42:35 [djw.628]



5ESS MSC

Version 1.0.0July 5, 1991 -- 10:42:35 [djw.628]



LAND TO ROAMING MOBILE CALL




5ESS MSC

CALL DELIVERY TO A MOBILE STATION

Via Gateway with External HLR

Version 1.0.0May 11, 1992 -- 07:45:20 [term.1]



5ESS MSC

CALL DELIVERY TO A MOBILE STATION

Via Gateway with External HLR

PSTN

VisitedMSC

BSS 2

BSS 1

MSISDN

MSISDN

Voice Path

Signaling

MSC

BSS 2

BSS 1

Gate-way

MSC HomePLMN

MSIS

DNM

SRN

TMSI

MSRN

MSRNNeedMSRN

TMSI

HLR

VLR 89

7

4 5

6

3

2

1




5ESS MSC


Routing Information Query

Version 1.0.0May 11, 1992 -- 07:45:20 [term.1]



5ESS MSC


Routing Information Query

Roaming NumberAcknowledge

Send RoutingInformation Result

...........................................................................................

HLR Query

HLRSM

PSTNSM

...........................................................................................

...........................................................................................

Allocate Trunkto VLR_MSC

C

...........................................................................................

AM

HLR MSC VLR MSCGateway MSC

RoutingWSM

D

IAM

Send RoutingInformation

VLRSM

...........................................................................................

Provide RoamingNumber

Version 1.0.0May 13, 1992 -- 17:27:59 [term.1]



5ESS MSC


Routing to VLR MSC and Paging

Version 1.0.0May 11, 1992 -- 07:45:32 [term.2]



5ESS MSC


Routing to VLR MSC and Paging

PerformPaging

Paging

PagingResponse

PagingResponse

...........................................................................................

ACM

ISUPSM

.............................................................................................

ISUPSM

.............................................................................................

ISUP

Setup Complete

ACM Received

ACM

...........................................................................................

AM

VLR MSCGateway MSC

PSTNSM

..........................................................................................

Setup Trunkto VLR MSC

IAM

Terminationto MS

PagingStarted

MSVLRSM BSS

...........................................................................................

............................................................................................

Version 1.0.0May 13, 1992 -- 17:31:45 [term.2]



5ESS MSC


Authentication, BSS Trunk Hunt, Ciphering

Version 1.0.0May 11, 1992 -- 07:45:36 [term.3]



5ESS MSC


Authentication, BSS Trunk Hunt, Ciphering

.............................................................................................

.............................................................................................

Gateway MSC

ISUPSM

ISUPSM

ISUP

.........................................................................................

BSS

VLR Information

SetupComplete

BSS Trunk Ready

Set Cipher Mode

Authentication Response

SetupBSS Trunk

AllocateBSS Trunk

Authentication Request

Cipher Mode Set

MS

............................................................................................

............................................................................................

...........................................................................................

...........................................................................................

TrunkWSMAM

VLRSM

VLR MSC

Version 1.0.0May 13, 1992 -- 17:34:15 [term.3]



5ESS MSC


Radio Channel Assignment, Call Connection

Version 1.0.0May 11, 1992 -- 07:45:39 [term.4]



5ESS MSC



CPG

CPG

Connect Acknowledge

Connect

Mobile Alerted

Call Confirm

ISUP

ANM

ISUPSM

PSTNSM

.........................................................................................

Gateway MSC

........................................................................................ANM

Answer

ISUPSM

AnswerNetworkAlerting

NetworkAlerting

VLR MSC

.............................................................................................

Setup

.............................................................................................

Radio AssignComplete

Assign RadioChannel

BSS MS

............................................................................................

...........................................................................................

TrunkWSM

Version 1.0.0May 13, 1992 -- 17:36:19 [term.4]



5ESS MSC

Version 1.0.0May 13, 1992 -- 17:36:19 [term.4]



INTRA-MSC HANDOVER




5ESS MSC

INTRA-MSC HANDOVER STEPS

The handover capability on the International 5ESS Mobile Switching Center (MSC) allows mobilesubscribers to continue active calls as the move through the different radio coverage areas handledby the MSC. As the mobile station moves, the call is transferred between Base Station Systems(BSSs). To help support this movement, the 5ESS allocates a trunk to the new BSS and internally"moves" the the data associated with the mobile station (terminal) to a new Wireless SwitchingModule (WSM).

The handover process on the International 5ESS Switch can be logically divided into the four steps(phases) as illustrated on the following page.

Version 1.0.0November 26, 1991 -- 14:06:58 [djw.423]



5ESS MSC

HANDOVER STEPS

• Handover Request from BSS

• Allocation of New Resources

• Handover Execution

• Release of Old Resources

Version 1.0.0May 26, 1991 -- 20:54:55 [djw.423]



5ESS MSC

4 STEPS TO A HANDOVER

SWITCHING VOICE PATHS

The following diagram illustrates the first two steps of a handover on the International 5ESS MobileSwitching Center (MSC). Let’s assume that the mobile station is engaged in a mobile-to-land voice call andis currently being served within a cell area under the control of BSS 1 (Base Station System). The initialvoice path for this call is through the following entities:

• BSS 1• WSM 1 (Wireless Switching Module)• Communications Module (CM)• SM 3• Public Switched Telephone Network (PSTN)

STEP 1: HANDOVER REQUEST (from BSS)The handover described in this scenario is intra-MSC inter-BSS. The handover process starts (from the MSCperspective) with a handover required message from BSS 1. Included in the message is a rank-ordered list ofqualified cell areas that meet BSS 1 requirements to receive the call. WSM 1, upon receiving this handoverrequired message will extract the first cell area from the rank-ordered list to determine which BSS controlsthe specified cell area. WSM 1 then determines the trunk group that serves the candidate BSS. There is aone-to-one mapping between a BSS number and trunk group number. WSM 1 forwards this trunk groupnumber along with the remaining candidate cell IDs (if any) to the Administrative Module (AM).

STEP 2: ALLOCATION OF NEW RESOURCESThe AM, upon finding an available trunk to the candidate BSS, will reserve the trunk and inform the WSMassociated with the trunk that it should begin preparation to receive a handover. In this example, it isassumed that the selected trunk terminates on WSM 2. The AM also reserves a new Time MultiplexedSwitch (TMS) path between WSM 2 and SM 3. WSM 2 then has three basic operations to perform:

• Inform SM 3 that it needs to establish another TMS path between itself and WSM 2.• Request the candidate BSS (BSS 2 in this scenario) to reserve a radio traffic channel, and pass BSS 2

the current Encription key, Kc.• Request WSM 1 to pass a copy of all call related data to WSM 2.

Once all of the above operations have been successfully performed, WSM 2 will inform WSM 1 that themobile station should be ordered to retune to the new radio traffic channel (which was reserved by BSS 2).

Note: each BSS connected to the 5ESS is represented by one trunk group (i.e., a 40 BSS system would have40 groups of trunks serving BSSs). Recalling from a previous discussion, it is possible (and preferred) thatthat a group of trunks serving one BSS be spread across several WSMs. It is possible that the WSM servinga given call (WSM 1 in this example) has trunks to both the serving BSS (BSS 1) and the candidate BSS(BSS 2). The handover trunk-hunt algorithm in the AM does not attempt to favor any particular WSM in itssearch for an available trunk. In other words, it is possible to have an available trunk from WSM 1 to BSS 2,but the AM select a trunk to BSS 2 that is associated with WSM 2; as assumed in this example.

BSS - Base Station System CM - Communications ModuleMS - Mobile Station PSTN - Public Switched Telephone NetworkSM - Switch Module TMS - Time Multiplexed SwitchTSI - Time Slot Interchanger WSM - Wireless Switch Module

Version 1.0.0May 26, 1992 -- 17:53:13 [djw.405]



5ESS MSC

4 STEPS TO A HANDOVER


WSM1

WSM2

SM3

TSI TSI TSI

BSS 1 BSS 2 PSTN

STEP 1: HANDOVER REQUEST (from BSS)

WSM1

WSM2

SM3

TSI TSI

BSS 1 BSS 2 PSTN

STEP 2: ALLOCATION OF NEW RESOURCES PivotSM

PassingWSM

ReceivingWSM

TrunkWSM

TMS path through the CM

New TMSpath

Version 1.0.0December 5, 1991 -- 12:50:01 [corel710.eps]



5ESS MSC

4 STEPS TO A HANDOVER - continue


In order to proceed to Step 3, all resources necessary to perform a handover must be allocated and ready. Ifone or more resources are not available, then a handover to the given cell area cannot be performed. In thissituation, WSM 2 would look to see if there is another cell on the rank ordered candidate list and if so,translate the next candidate cell ID to a BSS trunk group and then request the Administrative Module (AM)to search for an available trunk; a process very similar to what WSM 1 did back during Step 1.

Assuming all resources have been reserved, we proceed as follows.

STEP 3: HANDOVER EXECUTIONWSM 1 informs the VLR WSM that the call is about to be handed off from WSM 1 to WSM 2. Next, WSM1 instructs BSS 1 to order the mobile station to retune to a new radio traffic channel. The mobile station willtransmit an access burst on the new radio channel to BSS 2. BSS 2, upon receiving an access burst from themobile station will perform two operations:

• Help the mobile station align its transmission in the correct time slot by determining the mobile stationpropagation delay (the time between when the access burst arrived relative to when the BSS expectedthe access burst to arrive in the mobile station’s timeslot), and then sends physical channel informationto the mobile station asking it to advance it transmission by x number of bits.

• Send a handover detected message to WSM 2 informing it that the mobile station has almost completedits handover. WSM 2 uses this stimulus to ask SM 3 (the pivot SM) to switch paths from the old BSS(BSS 1) to the the new BSS (BSS 2).

Notice that the SM that actually performs the hot switch of paths is neither WSM, but the the other half to thecall--SM 3 in this example.

Once the mobile station aligns its transmission to fit precisely into the new radio channel timeslot, it willinform BSS 2 that it has successfully handed over. BSS 2 will forward this indication to WSM 2.

STEP 4: RELEASE OF OLD RESOURCESWSM 2, upon receiving the handover complete indication from BSS 2, will inform the WSM 1 that thehandover has completed. WSM 1 will then inform the VLR WSM that the handover has completed (whichalso results in a message being sent to BSS 1 to free up the old radio traffic channel), and request the AM tofree up the trunk to BSS 1 and the TMS path between WSM 1 and SM 3.

Upon conclusion of a handover, the passing WSM no longer has any association with the call--the receivingWSM owns the call.

BSS - Base Station System CM - Communications ModuleMS - Mobile Station PSTN - Public Switched Telephone NetworkSM - Switch Module TMS - Time Multiplexed SwitchTSI - Time Slot Interchanger WSM - Wireless Switch Module




5ESS MSC

4 STEPS TO A HANDOVER - continue


STEP 3: HANDOVER EXECUTION

STEP 4: RELEASE OF OLD RESOURCES

WSM1

WSM2

SM3

TSI TSI TSI

BSS 1 BSS 2 PSTN

WSM1

WSM2

SM3

TSI TSI

BSS 1 BSS 2 PSTN

PivotSM

TrunkWSM

ReceivingWSM

PassingWSM

Version 1.0.0November 26, 1991 -- 18:12:03 [corel711.eps]



5ESS MSC

INTRA-MSC HANDOVER

Part 1

Presented in the following scenario is an inter-BSS intra-MSC handover for an active mobile station involvedin a mobile-to-land call. This scenario presents details concerning message communication betweenprocessors within the 5ESS MSC. Many of the steps in this scenario can be further decomposed into inter-process message communication within the same processor. Inter-process message communication detailsare not presented here.6

1 At periodic intervals, the mobile station provides signal strength and signal quality measurementreports to its serving Base Station System (BSS). The BSS also monitors the strength and quality ofthe signal being received from the mobile station. This monitoring and measurement process, by boththe mobile station and serving BSS, continues for as long as the mobile station is up on either adedicated signaling channel or a voice/data traffic channel.

2 The serving BSS (soon to be the old BSS) determines from the measurement report data that there areone or more qualified cell areas that can serve the mobile station, and decides (based on some criteria)that a handover should be performed. The serving BSS reviews the candidate list to see if any of thecell areas are under its control, and in this example we’ll assume there are none. The serving BSSpackages the rank-ordered list of qualified candidate cell area identities (IDs) in a handover requiredmessage and sends this to the MSC.7 In this case the MSC is represented by the WSM managing thecall on the trunk to the serving BSS (commonly referred to as the "trunk WSM" or "passing WSM" in5ESS handover documentation); hereafter referred to as the passing WSM. The handover requiredsignaling message is routed the passing WSM via the WGSM.

3

4

5 The passing WSM upon receiving the handover required message, extracts from the rank-order list ofcandidate cell IDs the best candidate. The passing WSM then translates the cell identifier to a BSStrunk group number. The passing WSM then sends a message to the Administrative Module (AM)asking it to allocate a trunk to the candidate BSS. Included in the message is the BSS trunk groupnumber and the remaining cell area IDs (if any).

6 The AM, upon receiving this request, searches for an available trunk in the specified trunk group. Ifthe AM cannot find a trunk, the requesting WSM will be informed of the situation. Assuming the AMdoes find and reserve a trunk, the AM determines which WSM is associated with the new trunk,reserves an inter-SM voice path (Time Multiplexed Switch (TMS) path) between the new WSM (thereceiving WSM) and the pivot SM. The AM then sends a message to the receiving WSM informing itthat it should begin preparation to receive a handover. Included in the message are the following: trunknumber to the new BSS, inter-SM path number, and the rank-ordered list of qualified cell areas.

7 The receiving WSM, upon being informed that it has been nominated to receive a handover, firstinforms the pivot SM that a new inter-SM TMS path has been reserved by the AM. The pivot SM,upon receiving this indication, will send a message to the Communication Module (CM) requestingthat it setup the reserved path between the receiving WSM and the pivot SM. The pivot SM, uponcompleting this operation, is now "primed" and ready to switch paths to the new BSS when instructedto do so. In the mean time, the current talk path remains in use and is not affected by this message.

6 . For very specific details concerning handovers on the 5ESS MSC, you can find additional information inthe "Wireless Hand-over Feature" located on the International DSS library: " intldss/111001/v5121/75".

7 . See GSM 08.08, Version 3.9.2, Section 3.2.2.17 for cell identifier formats.




5ESS MSC

INTRA-MSC HANDOVER

Part 1

Signal strengthmeasurements

Handoverrequired

MSUm Old

BSSA Passing

WSM AM PivotSM

ReceivingWSM

1

2

3

4

Allocate newBSS trunk

Receivehandover

notification

Setup newinter-SM path

5

6

7

Initiatehandover

Handoverinitiated




5ESS MSC

INTRA-MSC HANDOVER

Part 2

8 The receiving WSM then informs the passing WSM that is has been selected to receive the handover.This is the first indication to the passing WSM regarding the identity of the receiving WSM.

9 The passing WSM then transfers a copy of VLR and signaling connection information to the receivingWSM. A couple examples of VLR and connection information include: the current encryption key, Kc,the mobile station directory number (MSISDN), and VLR WSM number associated with the mobilestation.

10 The receiving WSM sends a handover request message to the candidate BSS. Included in this messageis the encryption key, Kc, the candidate cell identifier, and terrestrial circuit identity code (trunknumber). The diagram on the following page suggests that the receiving WSM sends the messagedirectly to the new BSS. Actually, this message is sent to the new BSS via the WGSM. Since thehandover required message is the first message to the new BSS for the mobile station, the WGSM willinitiate the establishment of a Signaling Connection Control Part (SCCP) connection (i.e, a virtualchannel). Associated with the SCCP connection will be two WSMs: the VLR WSM and the receivingWSM.

11 The new BSS, upon receiving the handover required message, will determine which Base TransceiverStation (BTS) is associated with the candidate cell identifier, reserve a radio traffic channel, pass theencryption key value to the BTS, and connect the reserved radio to the MSC terrestrial circuit (trunk).Assuming a radio traffic channel is available, the new BSS sends a handover request acknowledgemessage with the reserved radio traffic channel number back to the MSC.

12 The receiving WSM forwards the handover request acknowledgment message to the passing WSM.

13 At this point in time, the passing WSM now knows that all the necessary resources have beenreserved/established to support a handover. Before executing the handover, the passing WSM transfersa copy of the call record (dynamic data pertaining to the call) to the receiving WSM. Included in thisdata, for example, is billing related information and the call processing state of the call.

Any call processing related messages sent to the passing WSM, associated with the mobile station,from now on will be queued and shipped to the receiving WSM after the handover has completed.

14 The receiving WSM acknowledges the receipt of the call record data.

15 The passing WSM informs the VLR WSM that the handover interval has started, signifying that therewill be a short open interval where messages cannot be reliably exchanged between the MSC andmobile station. The VLR WSM will queue any supplementary service and/or short messagesassociated with the mobile station until the handover has completed.




5ESS MSC

INTRA-MSC HANDOVER

Part 2

VLRWSM

PassingWSM

ReceivingWSM

NewBSS

A

New trunk WSM& BSS trunk

selected

Transfer copyof VLR record

Handover request

Handover requestacknowledge

Handover requestacknowledge

Transfer call record

Transferacknowledge

Handover started

8

9

10

11

12

13

14

15




5ESS MSC

INTRA-MSC HANDOVER

Part 3

16 The passing WSM instructs the serving BSS to send a handover command to the mobile station.Included in this message is the new radio traffic channel that was reserved on the new BSS.

17 The serving BSS transmits to the mobile station a handover command with the new radio trafficchannel number. Since the number of bytes associated with the handover command is rather large, theBSS steals voice time slots (discarding them) and inserts the handover command in the stolen slots.The rational, supposedly, behind this approach has to do with the notion that the logical out-of-bandsignaling channel associated with the voice channel has too low of bandwidth. This is the last messagethe serving base station sends to the mobile station.

18 The mobile station retunes to the new designated radio traffic channel and begins transmitting accessburst messages (mini packets with a lot of guard band) to the new BSS.

19 The new BSS, upon detecting that the mobile station is attempting to gain access to the new BSS,sends a handover detected message to the MSC. This message is a useful stimulus to the MSC toswitch the voice path from the old and new BSS. This message and the next message occur in parallel.

20 While the BSS is sending the handover detected message to the MSC, the receiving Base TransceiverStation (BTS), has the responsibility to work with the mobile station to align the mobile’s transmissionprecisely within its assigned time slot. The BTS accomplishes this by measuring the mobile stationtransmission propagation delay (the time between when the access burst arrived relative to when theBTS expected the access burst to arrive in the mobile station’s timeslot), and then sending physicalchannel information to the mobile station asking it to advance its transmission by x bits. Note: Thereare 8 timeslots per radio frequency. It is necessary to adjust when mobile stations begin theirtransmission to prevent two mobile stations on adjacent timeslot from interfering with each other.

21 The receiving WSM upon receiving the handover detected message, quickly sends a request to the pivotSM instructing it to switch the voice path to the receiving WSM.

22 Once the mobile station has correctly aligned it transmission within its designated timeslot, it sends ahandover complete message to its new serving BSS.

23 The new BSS informs the MSC that the mobile station has successfully performed the handover.

24 The pivot SM upon switching the voice paths, sends an acknowledgment back to the receiving WSM.

Note: it is not known what the exact timing relationship will be between messages 16 through 22, since thereare two activities occurring in parallel. The two most time critical events involve: getting the mobile stationto advance its transmission to fit precisely in its designated timeslot, and getting the handover detectedstimulus to the pivot SM as soon as possible to cause the voice path to be switched to the new BSS. It isrequired, from the GSM specifications, that the open voice interval not exceed 150 milliseconds.




5ESS MSC

INTRA-MSC HANDOVER

Part 3

MS OldBSS

PassingWSM

PivotSM

ReceivingWSM

NewBSS

Um A A

Handovercommand

Handovercommand

Handoveraccess

Handoverdetected

Physicalchannel

information

Switch paths

Handovercomplete

Handovercomplete

Switch pathcomplete

16

17

18

19

20

21

22

23

24




5ESS MSC

INTRA-MSC HANDOVER

Part 4

25 Once the receiving WSM receives the handover complete message from the BSS and the switch pathcomplete indication from the pivot SM, the receiving WSM informs the passing WSM that the handoverhas been completed.

26 The passing WSM lets the VLR WSM know that the handover has completed. The VLR WSM usesthis information to begin sending any supplementary service or short messages to the receiving WSM.

27 The VLR WSM sends a message to the WGSM requesting that the SCCP connection to the old BSS beterminated. The WGSM in turn sends a clear command to the old BSS.

28 The old BSS upon receiving a clear command releases the radio traffic channel (making it available foranother mobile station), disconnects the radio from the terrestrial facility (trunk) to the MSC, andterminates the SCCP connection that was associated with the mobile station.

29 In parallel with message 24, the passing WSM begins transferring messages (if any) to the receivingWSM that was received and queued since the time when the call record was transferred from thepassing to the receiving WSM (message 11).

Examples of messages that could be queued include off-hook and on-hook indications. It is possiblethat the mobile user has just started a call whereby the destination party has not picked up yet (stillalerting). While the mobile user is driving around listening to ringing tone, it is possible for ahandover to be performed. It is also possible (although statistically unlikely, but still possible) for thedestination party to go off-hook while the mobile station is being handed off. If this was to occur, andif the off-hook indication was delivered to the passing WSM, it would be queued.

30 All messages received from the passing WSM are acknowledged.

31 The passing WSM informs the pivot SM that the old inter-SM voice path (Time Multiplexed Switch(TMS) path) is no longer needed by setting the "E signaling bit" (busy/idle bit) to idle in the inter-SMtimeslot. The pivot SM, upon detecting the "E-bit discontinuity" situation, release all resourcesassociated with the old path. The Communication Module (CM) is not informed that the path is nolonger needed, so the CM will continue to switch timeslots from the passing WSM to the receivingWSM (which is harmless). Periodically (around 5 to 10 seconds) each SM sends a copy of theirnetwork timeslot busy/idle map to the AM. The next copy of the map, from either the passing orreceiving WSM, to the AM will result in the AM placing the inter-SM network timeslot back on thefree list.

32 The passing WSM informs the Administrative Module (AM) that the trunk between the passing WSMand the old BSS and the old inter-SM path can be freed.

Congratulations, you have made it through an intra-MSC handover scenario as implemented on theInternational 5ESS! As you can tell, a handover is not a trivial procedure when the MSC hardware andsoftware is highly distributed.

To some people, this scenario may seem quite detailed. For folks who must design/maintain handoversoftware in the 5ESS, this scenario barely touches all the detailed steps necessary to perform a handover. Thenext level of detail is beyond the scope of this course.




5ESS MSC

INTRA-MSC HANDOVER

Part 4

OldBSS

VLRWSM

PassingWSM

ReceivingWSM

PivotSM

AM

Handovercomplete

Handovercomplete

Release oldradio channel

Radio channelreleased

Transfer queuedmessages

(if any)

Transferacknowledge

Release oldpath

Release oldBSS trunk

25

26

27

28

29

30

31

32




5ESS MSC




INTER-MSC HANDOVER




5ESS MSC

4 STEPS TO INTER-MSC HANDOVER


Version 1.0.0May 11, 1992 -- 09:53:13 [hoterstp.1]



5ESS MSC

4 STEPS TO INTER-MSC HANDOVER


WSM2

WSM2

WSM5

WSM5

SM1

SM1

SM3

SM3

SM4

SM4

TSI TSI

TSI

TSI

TSI

TSI

TSI

TSI

TSI

BSS 1

BSS 1

BSS 2

BSS 2

PSTN

PSTN

STEP 1: HANDOVER REQUEST (from BSS)

STEP 2: ALLOCATION OF NEW RESOURCES

TrunkWSM

ControllingWSM

Path through CM

Path through CM

MSC A

MSC A

MSC B

MSC B

Inter-MSC Voice Facilities




5ESS MSC

4 STEPS TO INTER_MSC HANDOVER - continue


Version 1.0.0May 11, 1992 -- 09:53:20 [hoterstp.2]



5ESS MSC

4 STEPS TO INTER-MSC HANDOVER - continue


WSM2

WSM2

WSM5

WSM5

SM1

SM1

SM3

SM3

SM4

SM4

TSI

TSI

TSI

TSI

TSI

TSI

TSI

TSI

BSS 1

BSS 1

BSS 2

BSS 2

PSTN

PSTN

ControllingWSM

Path through CM

MSC A

MSC A

MSC B

MSC B

Inter-MSC Voice Facilities

STEP 3: HANDOVER EXECUTION

STEP 4: RELEASE OF OLD RESOURCES




5ESS MSC

INTER-MSC HANDOVER

Handover Required , New BSS Trunk Assignment

Version 1.0.0May 11, 1992 -- 07:45:53 [hoter.1]



5ESS MSC

INTER-MSC HANDOVER


ConnectionWSM

Call Controlling MSC

AllocateBSS Trunk

NewBSS

...........................................................................................


HandoverRequest

SetupBSS Trunk

.........................................................................................

...........................................................................................

AMA

NewWSM

PerformHandover

HandoverRequired

MSCall

ControllingWSM

Target MSC

MAPA

............................................................................................

...........................................................................................

Signal StrengthMeasurement

........................................................................................

OldBSS

.........................................................................................




5ESS MSC

INTER-MSC HANDOVER

ISUP Trunk Setup, Radio Channel Assignment




5ESS MSC

INTER-MSC HANDOVER

ISUP Trunk Setup, Radio Channel Assignment

AssignHandoverNumber

NewWSM

ConnectionWSM AM

Setup Complete

..........................................................................................

ISUPSM

ISUP


IAM

Set Inter-MSCTrunk

AllocateISUP Trunk

Radio Channel Acknowledge

CallControlling

WSM

Target MSC

..........................................................................................

.........................................................................................

.........................................................................................

ISUPSMAM

MAP

Time SlotNotification

AllocateNetwork TS

Setup New Path

Radio ChannelAcknowledge

..........................................................................................

..........................................................................................

..........................................................................................




5ESS MSC

INTER-MSC HANDOVER

Handover Command, Mobile Retune




5ESS MSC

INTER-MSC HANDOVER

Handover Command, Mobile Retune

............................................................................................


Handover Command

MS

Target MSC

.........................................................................................

MSis

Here

...........................................................................................

NewBSS

HandoverComplete

............................................................................................

HandoverDetected

NewWSM

ISUPSM

...........................................................................................

Wait forPre-determined Time

andPerform

Path Joining

Answer

ANM

Answer

CallControlling

WSM

ISUPISUPSM

VLRWSM

HandoverStarted

Target MSCReady

ACM

............................................................................................

...........................................................................................




5ESS MSC

INTER-MSC HANDOVER

Handover End, Old BSS Trunk Release




5ESS MSC

INTER-MSC HANDOVER

Handover End, Old BSS Trunk Release


ReleaseRadio Channel

Handover End

Send End Signal

Send EndSignal

........................................................................................

CallControlling

WSM

OldBSS

Target MSC

.........................................................................................

.........................................................................................

.......................................................................................

.........................................................................................

.........................................................................................

NewWSM

ConnectionWSM

VLRWSM

MAPAM


ReleaseBSS Trunk




5ESS MSC

5ESS TERMINOLOGY CLARIFICATION




5ESS MSC

5ESS TERMINOLOGY CLARIFICATION

• VLR WSM and VLR SM

• Passing WSM and Passing SM

• Receiving WSM and Receiving SM

• Trunk WSM and Trunk SM

• Pivot WSM and Pivot SM




5ESS MSC




Unit 7

Overview of Japan Cellular



The Japan Digital Cellular System


UNIT OVERVIEW

Version 1.0.0April 7, 1992 -- 12:59:10 [jjm.701]


7-2 The Japan Digital Cellular System


UNIT OVERVIEW

Japan Cellular TelephoneCompany Overview

Japan Cellular Network Scenarios

IDO Project Overview

Japan TelecommunicationStandards Overview



The Japan Digital Cellular System 7-3





Overview of Japan CellularJohn J. Mac Namara





WHAT ARE THE JAPAN CELLULAR NETWORKS?

What are the separate Frequency Bands issued for Cellular use?





JAPAN’S CELLULAR NETWORKS

1 . 800 MHz Band Analog - Cellular Telephone Companies– Nippon Telegraph & Telephone (NTT)– 8 New Common Carriers (NCCs)

• i.e., IDO, KCT, etc...

2 . 800 MHz Band Digital - Cellular Telephone Companies– Same as 800 MHz Analog

3 . 1.5 GHz Band Digital "PCN" - Cellular Telephone Companies– Nippon Telegraph & Telephone (NTT)– Tokyo Digital Phone (TDP)– Tu-Ka

4 . 1.9 GHz Band Digital "Personal Handy Phone (PHP)" - CellularTelephone Companies

– Nippon Telegraph & Telephone (NTT)– Other Companies Considering....

Version 1.0.0May 18, 1992 -- 19:44:07 [jjm.702.text]




JAPAN’s CELLULAR NETWORKS?

What are the 800 MHz Band Analog Cellular Telephone Companies?





800 MHz BAND ANALOG CELLULARTELEPHONE COMPANY OVERVIEW

• Nippon Telegraph & Telephone (NTT)– Began service 1974, Expanded 1979– Nationwide Service

• 8 New Common Carriers (NCCs) - Competition against NTT in1985

1 . Nippon Ido Tsushin (IDO)– Began service May, 1989– Serving Tokyo Metropolitan Area– Teleway Japan Corp Long-distance company

2 . Kansai Cellular Telephone (KCT)– Began service July, 1989– Serving Kansai District– Dai Ni Deden (DDI) Long-distance company

3 . Hokkaido Cellular Telephone Co.4 . Tohoku Cellular Telephone Co.5 . Hokuriku Cellular Telephone Co.6 . Chugoku Cellular Telephone Co.7 . Shikoku Cellular Telephone Co.8 . Kyushu Cellular Telephone Co.





WHAT ARE THE JAPAN CELLULAR NETWORKS?

What are the 800 MHz Band Analog Cellular Telephone Companies?





800 MHz BAND ANALOG CELLULARTELEPHONE COMPANY MAP

NTT is operating nationwide.The Kanto and Chubu regions areserved by IDO, and other areas by theeight companies of the Cellular Group.

Hokkaido CellularTelephone Co., Ltd.

Hokurika CellularTelephone Co., Ltd.

Kansai CellularTelephone Co., Ltd.

Chugoku CellularTelephone Cto., Ltd.

Kyushu CellularTelephone Co., Ltd.

Shikoku CellularTelephoneCo., Ltd.

Okinawa CellularTelephone Co., Ltd.(Scheduled to beginoperation in spring

1992)

Nippon Ido Tsushin Corp.

Tohoku CellularTelephone Co., Ltd.






What are the 800 MHz Band Terminal Unit Charges?





TERMINAL UNIT CHARGES800 MHz Band Analog

_ ____________________________________________________Category NTT IDO Cellular

Group_ _____________________________________________________ ____________________________________________________Product Name Mova-P Minimo HP-211_ ____________________________________________________Weight (g) 220 338 245_ ____________________________________________________Price of Unit (Y) 79,800 93,700 76,800_ ____________________________________________________Deposit (Y) 100,000 (2 yrs) -- --_ ____________________________________________________Monthly Fee (Y) 17,000 15,000 15,000_ ____________________________________________________Call Charge (Y) 277 240 2603 minutes_ ____________________________________________________






What are the 800 MHz Band Digital Cellular Telephone Companies?





800 MHZ BAND DIGITAL CELLULARTELEPHONE COMPANIES

• Nippon Telegraph & Telephone (NTT)– To Began service March 1993– Nationwide Service

• 8 New Common Carriers (NCCs) - Competition against NTT

° Nippon Ido Tsushin (IDO)– To Began service September, 1993– Serving Tokyo Metropolitan Area– Teleway Japan Corp Long-distance company

° Kansai Cellular Telephone (KCT)– Began service January, 1994 (??)– Serving Kansai District– Dai Ni Deden (DDI) Long-distance company

° 6 Other NCCs serving the remaining country






What are the 1.6 GHz Band Digital PCN Cellular Telephone Companies?





1.5 GHZ BAND DIGITAL PCNCELLULAR TELEPHONE COMPANIES

• Nippon Telegraph & Telephone (NTT)– Scheduled to Began service mid-1994– Nationwide Service

• Tu-Ka Cellular Tokyo Inc.– Scheduled to begin service mid-1994– Nationwide Service– Nissan Motor, Dai Ni Deden (DDI) & Foreign investment

• Tokyo Digital Phone– Scheduled to begin service mid-1994– Nationwide service– Japan Telecom Co Long-distance & Foreign investment






What are the 1.9 GHz Band Digital PHP’s Cellular Telephone Companies?





1.9 GHZ BAND DIGITAL PHP’sCELLULAR TELEPHONE COMPANIES

• Nippon Telegraph & Telephone (NTT)– Scheduled to Began service mid-1994– Selective Service

• Others ???





JAPAN’s TELECOMMUNICATION STANDARDS





JAPAN’S TELECOMMUNICATION STANDARDS

• Japan Digital Cellular Standards– Research & Development Center for Radio Systems (RCR)

Specification– Digital Mobile Network Inter-node (DMNI) Specification

• Other Standards - Japan’s SS7 based on CCITT– Telecommunication Technology Committee (TTC) C7

Specifications





JAPAN’s TELECOMMUNICATION STANDARDS





JAPAN’S TELECOMMUNICATION STANDARDS

TTCJT-

Q.702

TTCJT-

Q.701

......TTCJT-

Q.703

DMNI3.1

Japan’sSS7

Standards

Japan Standards

Japan’sDigital

CellularStandards

RCRSTD-27a





JAPAN TTC OVERVIEW





JAPAN TTC OVERVIEW

• Telecommunication Technology Committee (TTC) C7Specifications

– A subset of the CCITT (C7) Blue Book messages are used– Some additional charging messages are defined– TTC standards use JT-Q convention, For example:

– JT-Q701 Functional Description of the MTP of SS No. 7– JT-Q702 MTP Signaling Data Link– JT-Q703 MTP Signaling Link– JT-Q704 MTP Signaling Network Functions & Messages– JT-Q707 MTP Test and Maintenance– JT-Q761 Functional Description of the ISDN User Part of

Signaling System No. 7– JT-Q762 General Function of Messages and Signals– JT-Q763 Format and Code– JT-Q764 Signaling Procedures





JAPAN TTC OVERVIEW Diagram





JAPAN TTC OVERVIEW DIAGRAM

..............................

.......

. . . . . . . . . . . . . . . . . . ..................................................................

..........................................

..........................................................

...........................................................................................................................GMSCPLMN,

PSTN

VMSC

HLR

GLR

TTCISUP VMSC VMSC

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Voice Trunks

Signaling Links(TTC SS7 ISUP & MTP). . . . . . . . . . . . . . . . .

BSS BSS BSSBSS BSS BSSBSS

MS

BSSBSS

Version 1.0.0May 26, 1992 -- 13:51:44 [jjm.712]




JAPAN RCR OVERVIEW





JAPAN RCR OVERVIEW

• Research & development Center for Radio systems (RCR)

– RCR defines the Air Interface (Layers 1,2,3) between the MSand Network (Similar to GSM section 4.08)

– RCR Layer 3 covers Call Control (CC), Mobility Management(MM), and Radio frequency Transmission management (RT)(GSM’s RR).

– RCR sequencing of messages are slightly different– Some RCR message parameters are different– IMSI Attach/Detach is not used– No TMSI used– MS location area information is in HLR (No VLR)– MS is authenticated using NTT FEAL Algorithm (similar to

GSM)– RCR doesn’t define BSSMAP (GSM section 8.08), MSC &

BSC vendors must agree on a proprietary protocol (IDO’sSimilar to GSM 8.08)

– RCR doesn’t define Abis interface (BSC<-->BTS)– RCR defines 3 channel TDMA (GSM is 8 Channel TDMA)– RCR Layer 2 is LAPDm





JAPAN RCR OVERVIEW Diagram





JAPAN RCR OVERVIEW DIAGRAM

GMSC

PLMN,PSTN

VMSCVMSC

BSS

............................

...........................

............................BSSBSS BSS BSS BSS

............................

...........................

.............................

........

MS

...... ..............

..........

CC & MMOnly

RCR

RCR

Signalling Links. . . . . . . . . . . . . . . .

Voice

HLR

GLR

VMSC............................

...........................

............................BSS BSSBSS

Version 1.0.0May 26, 1992 -- 13:59:34 [jjm.714]




MSC<->BSS<->MS Protocol Model





MSC<->BSS<->MS PROTOCOL MODEL

BTSMSVMSC BSC

A A-bis

(Air)UmBSS

Layers 1 & 2&

Layer 3Radio Resource (RR)

BSSMAP & SS7

Layer 3Call Control (CC) & Mobility Management (MM)

RCR only specifiesLayer 1, 2, & 3 of Air Interface (CC, MM, RT)

GSM specifies BSSMAP, SS7, A-bis,& Layers 1, 2, & 3 of Air Interface (CC, MM, RR)

Version 1.0.0May 18, 1992 -- 20:11:19 [jjm.715]




JAPAN DMNI OVERVIEW





JAPAN DMNI OVERVIEW

• Digital Mobile Network Inter-node (DMNI) Specification

– DMNI defines Mobile Application Part (MAP) and ISDN UserPart (ISUP) for mobile communication purposes (GSM MAPSection 9.02)

– DMNI MAP has the same protocol stack and interface toTCAP

– VLRs are not used in the DMNI– DMNI HLRs are accesse more frequently and contain

dynamic data (i.e. Busy/Idle status - LM Control)– DMNI uses Gateway visitor Location Registers (GLR)– GLRs contain HLR data for visiting subscribers from other

networks– Supplementary Services only work in Home networks (not for

roaming)– Anchor-MSCs (A-MSC) and Float-MSCs (F-MSC) to handle

multi-MSC LAs and handoffs between MSCs– SCCP/MTP use 16 bit codes vs 14 bit for GSM– DMNI adds data (IEs) to the ISUP IAM message to handle

connections between MSCs– No EIR





JAPAN DMNI OVERVIEW Diagram

DMNI Signaling





JAPAN DMNI OVERVIEW DIAGRAM

DMNI Signaling

BSS

...................................................................

.................................

..........

.......

BSSBSS BSSBSSBSSBSSBSS

.......................................

GLR

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .VMSC

..............................

..........

.................................................................

.............................................

....................................

....................

....................

......

..........

..........

....... .......................................

..........................................................

............................................................

HLROther

PLMNEntities

GMSC

VMSC VMSC

BSS

. . . . . . . . . . . . . . .SS7 Signaling Links(MAP & ISUP)

Voice Trunks

...

...

...

...

...

...

.

...

.........................

Version 1.0.0May 26, 1992 -- 14:12:56 [jjm.717.1]





Area Definitions

• MSC - Mobile-services Switching Center• VMSC - Visitor Mobile-services Switching Center• GMSC - Gateway Mobile-services Switching Center• HLR - Home Location Register• GLR - Gateway visitor Location Register• GS - Gateway Switch• BSS - Base Station System• BTS - Base Transceiver System• MS - Mobile Station• CA - mobile-services switching center Control Area• LA - Location Area• SA - Service Area• OSPS - Operator Service Position System• 5ESS - No. 5 Electronic Switching System• AM - Administrative Module• CM - Communication Module• SM - Switch Module• WSM - Wireless Switch Module• RSM - Remote Switch Module• WRSM - Wireless Remote Switch Module• OMC - Operation Maintenance Center• MAP - Mobile Applications Part• ISUP - ISDN User Part• PSTN - Public Switch Telephone Network

Version 1.0.0May 1, 1992 -- 16:19:32 [jjm.717]





Area Definitions

VMSC

GLR

BSS BSS BSS BSS BSSBSS BSS

LACA & LA

CA CA

SA

.......

BSS

CA - Control Area (Area Controlled by MSC)LA - Location Area (May cover multpile CAs)VMSC <-> PSTN Direct Connect for Outgoing OnlyHLRs/GLRs - Integrated and Distributed among MSCsGMSC - Gateway Switch, Point of Interconnect for all Incoming TrafficSA - Service Area (IDO’s Digital Network Serving Area)

...

BSS

VMSCVMSC

GMSC

PLMN,PSTN

HLR

Version 1.0.0May 26, 1992 -- 14:16:51 [jjm.717.2]





GLOSSARY

• MSC - Mobile-services Switching Center• VMSC - Visitor Mobile-services Switching Center• GMSC - Gateway Mobile-services Switching Center• HLR - Home Location Register• GLR - Gateway visitor Location Register• GS - Gateway Switch• BSS - Base Station System• BTS - Base Transceiver System• MS - Mobile Station• CA - mobile-services switching center Control Area• LA - Location Area• SA - Service Area• OSPS - Operator Service Position System• 5ESS - No. 5 Electronic Switching System• AM - Administrative Module• CM - Communication Module• SM - Switch Module• WSM - Wireless Switch Module• RSM - Remote Switch Module• WRSM - Wireless Remote Switch Module• OMC - Operation Maintenance Center• MAP - Mobile Applications Part• ISUP - ISDN User Part• PSTN - Public Switch Telephone Network

Version 1.0.0May 1, 1992 -- 16:19:32 [jjm.717]





DMNI NETWORK MODEL

BSSBSSBSSBSSBSS

.......................................

GLR

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .VMSC

..............................

..........

.................................................................

.............................................

....................................

....................

....................

......

..........

..........

....... .......................................

..........................................................

............................................................

HLR

PLMN,PSTN

GMSC

VMSC VMSC

BSS

. . . . . . . . . . . . . . .SS7 Signaling Links(MAP & ISUP)

Voice Trunks

...

...

...

...

...

...

.

...

..........................

CA - Control Area (Area Controlled by MSC)LA - Location Area (May cover multpile CAs)VMSC <-> PSTN Direct Connect for Outgoing OnlyHLRs/GLRs - Integrated and Distributed among MSCsGMSC - Gateway Switch, Point of Interconnect for all Incoming TrafficSA - Service Area (IDO’s Digital Network Serving Area)

BSS

...................................................................

.................................

..........

.......

SA

CA CACA & LA

LA

BSSBSS

Version 1.0.0May 26, 1992 -- 14:09:55 [jjm.717]




JAPAN to GSM Model Comparison Diagram





JAPAN to GSM MODEL COMPARISON DIAGRAM

RCR specifies Air InterfaceDMNI specifies B,C,D,E,H,J

GLR

J

TTC ISUP

TTC ISUP

DHLR

PSTN

MSC

MSC

AUC

HLR

E

Other Networks

ISDN

H

VLR

B

C

MSC

MS

BTS

BSC

BSS

Air

EIR

Version 1.0.0May 18, 1992 -- 20:11:50 [jjm.718]




JAPAN Network Parameters





JAPAN NETWORK PARAMETERS

• MSN = Mobile Subscriber Number (DN)• Mobile Station Identifier (MSI) - Mobile Unit Number• RON = Roaming Number (DN) for visiting MSs (GLR allocates)• RMI = Roaming Number Unit Number for visiting MSs (GLR

allocates)• PRN = Routing Number - Identifies the MSC• LI = Location Information• FLI = Floating Location Number

JAPAN vs GSM Comparison

_ ______________________________________Japan Term GSM Term_ _______________________________________ ______________________________________MSN MS ISDN_ ______________________________________MSI IMSI_ ______________________________________RON MSRN_ ______________________________________RMI Roamer’s IMSI_ ______________________________________PRN MSC Routing Number_ ______________________________________LI LAI_ ______________________________________FLI LI Changed during Call_ ______________________________________

Version 1.0.0April 7, 1992 -- 14:00:54 [jjm.719.text]




Version 1.0.0April 7, 1992 -- 14:00:54 [jjm.719.text]



IDO Overview





IDO Overview





IDO OVERVIEW

• 800 MHz Band Analog Network– Vendors: NEC, Motorola

• 800 MHz Band Digital Network– Vendors: NEC, AT&T, Fujitsu– Working Group Meetings with vendors (in Japanese)

° KO (Technical) WG meeting - Weekly, 30 to 60submissions each week

° HN (Maintenance) WG meetings - Monthly(sometimes Bi-weekly)

° SN (System) WG Meeting - Monthly

– Kiba Software Center in Tokyo, Japan -– MSCs & BSSs Interface Testing– Verifying Vendor’s Progress to IDO





IDO’s Network Architecture





IDO’s NETWORK ARCHITECTURE

.................................

BSS

GMSCGMSCPLMN,

PSTN

VMSCwith HLR& GLR

VMSCwith HLR& GLR

VMSCwith HLR& GLR

IDO’s Vendors:VMSCs (with HLR & GLR) - NEC, AT&T, & FujitsuBSSs - NEC & Fujitsu (AT&T - Linear Amps.)GMSCs - NECSTP - NEC

BSSBSS BSS BSS BSSBSS BSS

......

...............

....................

...................................................................

........................................

STP

BSS

.............................

Version 1.0.0May 18, 1992 -- 14:03:58 [jjm.721]




IDO’s 5ESS Architecture





IDO’s 5ESS ARCHITECTURE

. . . . . . . . . Voice TrunksSignaling Links

MAP

ISUP

GS, MSCs& Other Mobile

Networks

ISUP

PSTN &Other Networks

C7BSC Maint. C7

BX.25

...

...

...

...

...

...

...

...

...

...

...

...

...

...

..

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .BillingCenter

OMC

WirelessSM

HLR,GLR

WirelessSM

HLR,GLR

PSTNGlobal SM

WirelessGlobal SM

WirelessSM

HLR,GLR .......................................................

.........................................................

...

...

...

...

...

...

...

...

...

...

...

...

...

...

...

...

...

...

...

...

...

..... ....

CM

AM

5ESSMSC

. . . . . . . . . . . . . . . . . . .

BSC ......

......BTS

RCR AirInterface

BTS

Version 1.0.0May 18, 1992 -- 14:03:58 [jjm.722]




IDO’s 5ESS Supplementary Services





IDO’s SUPPLEMENTARY SERVICES





IDO Documentation Status





IDO DOCUMENTATION STATUS

_ ________________________________________________________________DOCUMENT NAME TRANS COMMENTS

STATUS_ _________________________________________________________________ ________________________________________________________________RCR Standard Cmpltd IDO Air InterfaceRCR-STD 27aDRAFT_ ________________________________________________________________RCR Standard Inprog IDO Air InterfaceRCR-STD 27aFINAL - 1/30/92_ ________________________________________________________________DMNI Standard Cmpltd Intra & Inter-Network InfoVersion 3.1 MAP & ISUP_ ________________________________________________________________IDO Background Cmpltd IDO Mobile Telephone SystemInfo (#081291) Description - General_ ________________________________________________________________NS-0201 (#284) Cmpltd IDO System & NetworkIDO System Spec Description_ ________________________________________________________________NS-0202 (#305) Cmpltd IDO Suppl. Service Desc.IDO Service Spec_ ________________________________________________________________NS-0203 (#243) Cmpltd IDO Maintenance InformationIDO Maint ControlSpec_ ________________________________________________________________IDO WG Summary Cmpltd Summarizes IDO WG DecisionsKou 17-26 List Relevant WG Kou Documents(#422)_ ________________________________________________________________Kou 20-37 Cmpltd IDO Gateway Specification_ ________________________________________________________________JT-Q.763 (#183) Cmpltd TTC ISUP StandardsJT-Q.703JT-Q.704 (#168)JT-Q.707 (#387)JT-Q.730 (#384)JT-Q.762 (#385)JT-Q.764 (#383)JT-Q.766 (#386)_ ________________________________________________________________NTT MTP Book Cmpltd NTT’s MTP Signaling Info.(#306)_ ________________________________________________________________JDC A-Inter Spec Cmpltd BSSMAP (MSC<->BSS) Draft

from NEC, Version 0.3_ ________________________________________________________________








Japan Cellular Network Call Scenarios





Location Registration

Home Subscriber





LOCATION REGISTRATION

HOME SUBSCRIBER

1. 5.

V-MSC

1. MS Sends LU Request (MSI)2. V-MSC Requests Authentication data from HLR3. HLR sends Auth. Data to V-MSC for processing4. V-MSC sends PRN & LI to HLR for registration5. V-MSC send LU Accept to MS

HLR

4.3.2.

MS

Version 1.0.0May 18, 1992 -- 14:03:59 [jjm.725]




Location Registration

Visiting Subscriber





LOCATION REGISTRATION

VISITING SUBSCRIBER

1. MS Sends LU Request (MSI)2. V-MSC Requests Authentication data from GLR3. GLR request/obtains Auth. Data from HLR4. GLR sends Auth. Data to V-MSC for processing5. V-MSC sends PRN & LI to GLR for registration6. GLR allocates the RON and sends to HLR7. HLR records RON & sends MS data to GLR8. GLR copies MS data and sends LU Accept to MS thru V-MSC(MSI is used by MS for LU, Orig, & Term)

1.

V-MSC

3.

8.

GLR

8. 5. 4. 2.

MS

Network 1Network 2

HLR

7.

6.

Version 1.0.0May 18, 1992 -- 20:18:22 [jjm.726]




Call Termination

Home Subscriber





CALL TERMINATION - Home MS

6.

MS

V-MSC(F-MSC)

V-MSC(F-MSC)

V-MSC(A-MSC) 8.

LA

5. 5.

7.6. 6.

8.

G-MSCPLMN,PSTN

1.

4.

3.2.

HLR

1. PSTN/PLMN sends IAM message with MSN to G-MSC2. G-MSC accesses HLR using MSN as key3. G-MSC obtains PRN & LI and routes to V-MSC4. G-MSC sends IAM message to V-MSC which becomes A-MSC5. A-MSC sends General page to all V-MSCs in LA6. All V-MSCs page MS using MSI7. MS responds with Page Response8. This V-MSC becomes F-MSC & a connection is madefrom G-MSC <-> A-MSC <-> F-MSC

Version 1.0.0May 29, 1992 -- 16:35:45 [jjm.727]




Call Termination

Visitor





CALL TERMINATION - Visitor

1. PSTN/PLMN sends IAM message with MSN to G-MSC of NW 22. G-MSC accesses HLR using MSN3. G-MSC obtains RON from HLR4. G-MSC sends IAM message with RON to G-MSC of NW 15. G-MSC accesses GLR using RON6. G-MSC obtains PRN & LI from GLR and routes to V-MSC7. V-MSC pages MS using RMI8. MS responds with Page Response

5.

Network (NW) 1 Network (NW) 2

HLR

6.3.

4.1.PLMN,PSTN

G-MSC

V-MSC

G-MSC

2.

6.

GLR

MS

7. 8.

Version 1.0.0May 18, 1992 -- 20:09:02 [jjm.728]




Version 1.0.0May 18, 1992 -- 20:09:02 [jjm.728]



Appendix 1

Index to GSM Specification Document

Version 1.0.0April 1, 1993 -- 09:53:42 [unita1.x]




_ ___________________________________________________________________________________ _________________________________________________________________________________SPEC TITLE VERSION

NUMBER NUMBER_ __________________________________________________________________________________ _________________________________________________________________________________01.02 General Description of a GSM PLMN 3.0.001.04 Vocabulary in a GSM PLMN 3.0.101.06 Service Implementation Phases and Possible Further Evolution 3.0.2

Phases in the GSM PLMN_ _________________________________________________________________________________02.01 Principles of Telecommunication Services Supported by a 3.2.0

GSM PLMN02.02 Bearer Services Supported by a GSM PLMN 3.2.002.03 Teleservices Supported by a GSM PLMN 3.4.002.04 General on Supplementary Services 3.7.102.05 Simultaneous and Alternate Use of Services 3.0.202.06 Types of Mobile Stations 3.2.0

02.06 DCS Types of Mobile Stations 3.0.002.07 Mobile Station Features 3.4.102.08 Quality of Service 3.0.002.09 Security Aspects 3.0.102.10 Provision of Telecommunication Services 3.0.102.11 Service Accessibility 3.6.0

02.11 DCS Service Accessibility 3.1.002.12 Licensing 3.0.102.13 Subscription to the Services of a GSM PLMN 3.1.002.14 Service Directory 3.0.102.15 Circulation of Mobile Stations 3.0.102.16 International Mobile Station Equipment Identities 3.0.102.17 Subscriber Identity Modules (SIM)- Functional Characteristics 3.2.002.20 Collection Charges 3.0.102.21 Transferred Account Procedure and Billing Information 3.3.002.24 Description of Advice of Charge 3.0.002.30 Man-Machine Interface (MMI) of the Mobile Station 3.9.002.40 Procedures for Call Progress Indications 3.2.002.81 Number Identification Supplementary Services 4.0.102.82 Call Offering Supplementary Services 3.6.102.83 Call Completion Supplementary Services 3.0.002.84 Multi Party Supplementary Services 4.3.002.85 Community of Interest Supplementary Services 3.0.002.86 Charging Supplementary Services 3.0.002.87 Additional Information Transfer Supplementary Service 3.0.002.88 Call Restriction Supplementary Services 3.6.1_ _________________________________________________________________________________03.01 Network Functions 3.1.103.02 Network Architecture 3.1.403.03 Numbering, Addressing, and Identification 3.5.003.04 Signaling Requirements Relating to Routing of Calls to Mobile 3.1.0

Subscribers03.05 Technical Performance Objectives 3.2.003.07 Restoration Procedures 3.2.103.08 Organization of Subscriber Data 3.7.003.09 Handover Procedures 3.2.103.10 GSM PLMN Connection Types 3.3.003.11 Technical Realization of Supplementary Services - General 3.1.1

Aspects03.12 Location Registration Procedures 3.3.0

03.12 DCS Location Registration Procedures 3.0.1_ __________________________________________________________________________________ __________________________________________________________________________________



Appendix 1-2.1 The Pan-European GSM Cellular System


03.13 Discontinuous Reception (DRX) in the GSM System 3.0.203.14 Support of DTMF via the GSM System 3.0.203.20 Security-related Network Functions 3.3.203.40 Technical Realization of the Short Message Service - 3.5.0

Point-to-point03.41 Technical Realization of the Short Message Service - 3.4.0

Cell Broadcast03.42 Advanced Message Handling System (MHS) Access 3.0.003.43 Technical Realization of Videotex 3.0.103.44 Support of Teletex in a GSM PLMN 3.0.103.45 Technical Realization of FAX Group3 - Transparent 3.2.003.46 Technical Realization of Facsimile Group 3 Service - 3.2.0

Transparent03.48 GSM SMS - Cell Broadcast 3.0.003.50 Transmission Planning Aspects of the Speech Service in the GSM 3.2.2

PLMN System03.70 Routing of Calls to/From PDNs 3.0.003.81 Technical Realization of Number Identification Supp. Service 2.0.003.82 Technical Realization of Call Offering Supplementary Services 3.2.103.83 Technical Realization of Call Completion Supplementary Services 3.0.003.84 Technical Realization of Multi Party Supplementary Services 2.0.003.88 Technical Realization of Call Restriction Supplementary 3.2.0

Services_ _________________________________________________________________________________04.01 MS-BS Interface - General Aspects and Principles 3.0.104.02 GSM PLMN Access Reference Configuration 3.0.204.03 MS-BS Interface - Channel Structures and Access Capabilities 3.0.304.04 Layer 1 - General Requirements 3.3.404.05 Data Link Layer - General Aspects 3.1.504.06 MS-BSS Interface Data Link Layer Specification 3.9.004.07 Mobile Radio Interface Signaling Layer 3 - General Aspects 3.3.304.08 Mobile Radio Interface Layer 3 Specification 3.13.0

04.08 DCS Mobile Radio Interface Layer 3 Specification 3.1.004.10 Mobile Radio Interface Layer 3 - Supplementary Services 3.2.3

Specification General Aspects04.11 Point-to-Point Short Message Service Support on Mobile Radio 3.3.0

Interface04.12 Cell Broadcast Short Message Service Support on Mobile Radio 3.2.1

Interface04.21 Rate Adaptation on the MS-BSS Interface 3.4.004.22 Radio Link Protocol (RLP) for Data and Telematic Services on 3.7.0

MS/BSS Interf. and BSS/MSC Interf.04.80 Mobile Radio Interface Layer 3 Supplementary Services 3.2.0

Specification - Formats and Coding04.81 Mobile Radio Interface Layer 3 Number Identification 1.3.0

Supplementary Services Specification04.82 Mobile Radio Interface Layer 3 Call Offering Supplementary 3.1.3

Services Specification04.83 Mobile Radio Interface Layer 3 Call Completion Supplementary 2.1.0

Services Specification04.84 Mobile Radio Interface Layer 3 of Multi Party Supplementary 2.0.1

Services Specification04.88 Mobile Radio Interface Layer 3 Call Restriction Supplementary 3.1.3

Services Specification_ _________________________________________________________________________________05.01 Physical Layer on the Radio Path - General Description 3.3.2_ __________________________________________________________________________________ __________________________________________________________________________________



The Pan-European GSM Cellular System Appendix 1-2.2


05.01 DCS Physical Layer on the Radio Path - General Description 3.0.005.02 Multiplexing and Multiple Access on the Radio Path 3.6.105.03 Channel Coding 3.5.105.04 Modulation 3.1.205.05 Transmission and Reception 3.13.0

05.05 DCS Transmission and Reception 3.1.005.08 Radio Sub-system Link Control 3.7.0

05.08 DCS Radio Sub-system Link Control 3.0.005.10 Radio Sub-system Synchronization 3.5.0_ _________________________________________________________________________________06.01 Speech Processing Function- General Description 3.0.006.10 Full Rate Speech Transcoding 3.2.006.11 Substitution and Muting of Lost Frames for Full Rate Speech 3.0.1

Traffic Channels06.12 Comfort Noise Aspects for Full Rate Speech Traffic 3.0.106.31 Discontinuous Transmission (DTX) for Full Rate Speech Traffic 3.1.0

Channels06.32 Voice Activity Detection 3.0.0_ _________________________________________________________________________________07.01 General on Terminal Adaptation Functions for Mobile Stations 3.13.007.02 Terminal Adaptation Functions (TAF) for Services Using 3.7.1

Asynchronous Bearer Capabilities07.03 Terminal Adaptation Functions for Services Using Synchronous 3.4.0

Bearer Capabilities_ _________________________________________________________________________________08.01 General Aspects of the BSS-MSC Interface 3.0.108.02 BSS-MSC Interface - Interface Principles 3.3.108.04 BSS-MSC Interface - Layer 1 3.0.308.06 Signaling Transport Mechanisms Between BSS and MSC 3.5.208.08 MSC to BSS Interface - Layer 3 3.10.008.09 Network Management Signaling Support Related to the BSS 3.0.108.20 Rate Adaptation on BSS/MSC Interface 3.1.208.51 BSC-BTS Interface 3.0.208.52 BSC-BTS Interface - Interface Principles 3.0.208.54 BSC-BTS Interface - Layer 1 3.0.108.56 BSC-BTS Interface - Layer 2 3.1.108.58 BSC-BTS Interface - Layer 3 3.5.0

08.58 DCS BSC-BTS Interface - Layer 3 3.0.008.59 BSC-BTS Interface - O&M Signaling Transport 3.1.008.60 Inband Control of Remote Transcoders and Rate Adaptors 3.3.0_ _________________________________________________________________________________09.01 General Aspects of PLMN Interworking 3.0.109.02 Mobile Application Part (MAP) 3.8.0

09.02 DCS Mobile Application Part (MAP) 3.0.009.03 Signaling Requirements on Interworking Between the ISDN or 3.0.1

PSTN and the PLMN09.04 Interworking Between the PLMN and the CSPDN 3.0.109.05 Interworking Between the PLMN and the PSPDN for PAD Access 3.2.209.06 Interworking Between a PLMN and a PSPDN/ISDN for Support of 3.0.0

Packet Data09.07 General Requirements on Interworking Between the PLMN and the 3.8.0

ISDN or PSTN09.09 Detailed Signaling Interworking Within the PLMN and with the 3.0.0

PSTN/ISDN09.10 Information Element Mapping Between MS-BSS/BSS-MSC Signaling 3.0.2

Procedures and MAP09.10 DCS Information Element Mapping Between MS-BSS/BSS-MSC Signaling 3.0.0

_ __________________________________________________________________________________ __________________________________________________________________________________



Appendix 1-2.3 The Pan-European GSM Cellular System


Procedures and MAP09.11 Signaling Interworking for Supplementary Services 3.0.1_ _________________________________________________________________________________11.01 Principles of Type Approval Procedure for GSM Mobile Stations 3.0.0

11.10 DCS DCS 1800 Mobile Station Conformity Specifications 3.4.011.10 Mobile Station Conformity Specifications 3.10.011.11 Specification of the Internal Logical Organization of the SIM 3.12.0

and its Interfaces11.11 DCS Specification of the Internal Logical Organization of the SIM 3.3.0

and its Interfaces11.20 DCS GSM DCS 1800 BSS - Equipment Specification 3.1.0

11.20 GSM BSS - Equipment Specification 3.7.011.30 Mobile Services Switching Center 3.2.111.31 Home Location Register Specification 3.2.111.32 Visitor Location Register Specification 3.2.1

11.40 DCS System Simulator Specification 3.2.0(MS conformance test system)

11.40 System Simulator Specification 3.6.0(MS conformance test system)_ _________________________________________________________________________________

12.00 Objective & Structure of Network Management 3.0.412.01 Common Aspects of GSM Network Management 3.0.112.02 Subscriber, Mobile Equipment, and Services Data 3.1.0

Administration12.03 Security Management 3.0.112.04 Performance Data Measurements 3.2.112.05 Subscriber Related Event and Call Data 3.2.012.06 GSM Network Change Control 3.0.212.07 Operations and Performance Management 3.0.212.10 Maintenance Provisions for Operational Integrity of MSs 3.0.112.11 Maintenance of the Base Station System 3.1.112.13 Maintenance of the MSC 3.0.212.14 Maintenance of Location Registers 3.0.212.20 Network Management Procedures and Messages 3.3.012.21 Network Management Procedures and Messages on the A-bis 3.1.0

Interface_ __________________________________________________________________________________ __________________________________________________________________________________



The Pan-European GSM Cellular System Appendix 1-2.4

Appendix 2

Obtaining Copies of the GSM Recommedations





REQUESTING A COPY OF GSM VIA LINUSStep 1

In order to gain access to the databases available through LINUS, you need to have an accesspassword registered and confirmed by the AT&T Information Services Network.

To register for LINUS, call the Information Services Network Customer Support group at 908-582-4840.

Assuming you have a password registered on the LINUS machine, there are several different waysto access the database. Some of the following methods might not be available on your local UNIXmachine.

1 . From a UNIX Machine

a . linus (at the UNIX prompt)

b . dk linus

c . rlogin mhuxd -l linus

d . rlogin mhuxd.att.com -l linus

e . dkcu nj/mtdka/linus

• login as linus

f . cu -s2400 9085821725

• login as linus

2 . From DATAKIT DESTINATION Prompt

a . linus

b . nj/mtdka/linus

• login as linus

3 . Dial In

a . (908) 582-1725

• login as linus

4 . Internet Address

• 125.20.95.1



Appendix 2-2 The Pan-European GSM Cellular System



DEST INATION:

login:

Welcome to l inus! !

Erase char is backspace, l ine k i l l i s @

Enter L ibrary Network password:

nj/mtdka/l inus

l inus

terminal :

Enter your ID ( i .e . PAN or SS#):



The Pan-European GSM Cellular System Appendix 2-3








WELCOME TO LINUS!

L INUS Customer Help Desk (908) 582-4840, opt ions 1 & 1

************************************************************************TYPE TYPE

THIS FOR THIS

-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

db name Database you know by database name or # db #

feedback Provide FEEDBACK about L INUS (72)

index INDEX searching al l L INUS databases (128)

l inus L INUS info & PASSWORD changes/cancel lat ions (21)

ln Latest L INUS News [ last updated Mar 03\ (95)

menu MENU ass i s tance with database select ion (502)

NOTE:

===> ?l i s t - see DATABASE l i s t ?4 - HELP with database number 4

Enter a number, a name, the in i t ia l part of a name, or

? for GENERAL HELP, <return> to redisp lay screen, q to QUIT : 123

Version 1.0.0March 13, 1992 -- 00:56:25 [corel774.eps]










GSM RECOMMENDATIONS DATABASE

GSM Search Helps (Use +/- keys, tab, or i tem name to move to an item)

(Hi t return to se lect an item)

recommend Search on the recommendat ion t i t les

index Peruse the index for re levant recommendat ions

gsm. info Read or obtain a copy of infor mat ion on GSM and this database

feedback Give feedback concerning this onl ine GSM database

quit Quit th is GSM database search sess ion ent i re ly

A ***CELLULAR SYSTEMS ENGINEERING*** database

provided through the AT&T Informat ion Serv ices Network

Do general keyword searching on al l textsearch











Welcome to the ***GSM RECOMMENDATIONS and WORKING PAPERS DATABASE***

Database has 684 i tems. Last update was Mar 12 1992

Enter terms (words, numbers , locat ions) descr ib ing your search ? for HELP

q to quit

==>

--- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

A ***CELLULAR SYSTEMS ENGINEERING DEPTARTMENT*** database

provided through the AT&T Informat ion Serv ices Network

2.17











Set of 1 i tems. On item 1 of 1. Record disp lay: Page 1 of 2

Order Number: gsm-10020

T i t le: Subscr iber Ident i ty Modules : funct ional character i s t ics .

Source of document: ETS I/GSM/PT12

ETS I/TC/GSM

Document type: Recommendat ion

Recommendat ion Number(s) : GSM 02.17

Release Date: March 1990 Pages: 11 p.

Vers ion: 3.2.0 Previous vers ion: 3.1.1

Meet ing Body( ies) : Publ ic Land Mobi le Network.

Subject Headings: Mobi le communicat ion systems--Access contro l .

Te lecommunicat ion networks- -Access contro l .

Customer serv ice (Te lecommunicat ion)

Notes:

Changes agreed at GSM 26 are included.

-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

. Do a new search p Pr int present disp lay

+/- Move forward/back in disp lay = Put up br ief disp lays

r Request present i tem b Browse s imi lar i tems

Enter des i red act ion: r





GSM DOCUMENT COLLECTION CONTACTS

If you have a need to consult a set of the GSM recommendations or contact someone about GSMdocuments there are complete sets of these documents at four Bell Labs locations.

All of the individuals listed within the table have made an agreement with the AT&T librarynetwork to provide this service.





GSM DOCUMENT COLLECTION CONTACTS

_ ________________________________________________GSM Documentation Collection Contacts_ ________________________________________________

Loc. Room Name e-mail_ _________________________________________________ ________________________________________________WH 1D-308C Chris Capece mhuxo!sodaWH 14A-464 Uday Kapadia whserva!uskIHP 2F-523 Steve Raiman ihlpk!raimanIH 4J-415 Han Schiet ihlpl!jjs0IHC 1H-418 Mary Ann Wator ihlpf!mwator_ ________________________________________________








Appendix 3

Glossary of GSM Terms -- GSM 01.04

Version 1.0.0March 27, 1992 -- 09:05:35 [page.2]




ETSI/TC GSM

Title : Recommendation GSM 01.04Vocabulary In A GSM PLMN.

Version : 3.0.1Date : February 1991

------------------------------------------------------------------

TABLE OF CONTENTS

1. GENERAL 3-31.1 Scope 3-31.2 Introduction 3-3

2. VOCABULARY 3-42.1 General 3-42.2 Services 3-42.3 Networks 3-112.4 Stations 3-142.5 Access 3-162.6 Location and handover 3-182.7 Identity and Security 3-212.8 Administrative and commercial definitions 3-242.9 Operations and maintenance 3-262.10 Expressions related to the radiosubsystem 3-302.11 Miscellaneous 3-36

3. ABBREVIATIONS AND ACRONYMS 3-374. ALPHA SORTED INDEX 3-46





1. GENERAL

1.1 Scope

These are the terms, definitions and abbreviations to be used throughout the GSM recommendations.

The definition, or reference to a definition, in this recommendation 01.04 is valid in all recommendationswhere no definition is given within that recommendation. Where a definition, or a reference to a definition forthe same term, is given in both this recommendation 01.04 and in another and the definitions are different,then the definition given in that recommendation takes priority in only that recommendation.

1.2 Introduction

This recommendation consists primarily of those terms and definitions that are considered essential to theunderstanding and application of the principles of a GSM PLMN.

A number of terms are followed by their usual abbreviation, in parenthesis. A listing by abbreviation isprovided in chapter 3 of this recommendation. A number of terms have a GSM recommendation numberindicated after the term (e.g. 03.02). This indicates that reference should be made to that recommendation forthe full definitions of the term. Where both a reference and a definition is given in this recommendation, thedefinitions given here embrace only the essential concepts and on that basis it is considered that they are notinconsistent with the more specialized definitions that appear in those other recommendations. A number ofthe terms and definitions in this recommendation are identical to those found in CCITT RecommendationI.112, but they are applied to a GSM PLMN instead. The notes complementing CCITT I.112 Rec. definitionsare not considered to be part of the definitions. When applicable they have been reproduced.

References to these definitions are given in parenthesis, for example (110), as an aid to ensuring consistencybetween the two recommendations in the event of amendments. Whenever necessary GSM notes have beenadded regarding the application to a GSM PLMN.

Any term in common usage but whose use is deprecated in the sense defined, is shown as in the followingexample "419 FUNCTIONAL GROUP [FUNCTIONAL GROUPING]".

Where a truncated term is widely used in an understood context the complete term is quoted following thecolloquial form, for example, "201 SERVICE, TELECOMMUNICATION SERVICE".

Where a reference is made to the Radio Regulations the definition has been taken verbatim from that source(except where indicated) even though there may be some aspects that are not applicable to GSM. The RadioRegulations are published by the International Telecommunications Union ITU.and have the effect of aninternational treaty. For this reason it is deemed inadvisable to alter or truncate such references simply toensure complete relevance to GSM.





2. VOCABULARY

2.1 General

101 Telecommunication (110)

Any transmission and/or emission and reception of signals representing signs, writing, images and sounds orintelligence of any nature by wire, radio, optical or other electromagnetic systems.

2.2 Services

201 Service, telecommunication service (201)

That which is offered by an administration or RPOA to its customers in order to satisfy a specifictelecommunication requirement.

202 Radiocommunication service

A service as defined in this section involving the transmission, emission and/or reception of radio waves forspecific telecommunication purposes. In these Regulations, unless otherwise stated, any radiocommunicationservice relates to terrestrial radiocommunication. (Quoted from the Radio Regulations Nx 20).

203 Mobile service

A radiocommunication service between mobile and land stations, or between mobile stations. (Quoted fromthe Radio Regulations Nx 26).

204 Land Mobile Service

A mobile service between base stations and land mobile stations, or between land mobile stations. (Quotedfrom the Radio Regulations Nx 28).

205 Bearer service (202)

A type of telecommunication service that provides the capability for the transmission of signals betweenuser-network interfaces. Note: The GSM PLMN connection type used to support a bearer service may beidentical to that used to support other types of telecommunication service.

206 Teleservice (203)

A type of telecommunication service that provides the complete capability, including terminal equipmentfunctions, for communication between users according to protocols established by agreement betweenadministrations and/or RP0As.

207 Demand service, demand telecommunication service (205)

A type of telecommunication service in which the communication path is established almost immediately, inresponse to a user request effected by means of user-network signalling.





208 Service attribute, telecommunication service attribute (208)

A specified characteristic of a telecommunication service.

209 Basic services

The telecommunication services excluding the supplementary services (in accordance with table 1/I.210).

210 Supplementary service

A modification of, or a supplement to, a basic telecommunication service.

211 Calling line identification presentation

The supplementary service which provides for the called party with the possibility to receive identification ofthe calling party.

212 Calling line identification restriction

A supplementary service offered to the calling party to prevent presentation of the calling party’sISDN/MSISDN number to the called party.

213 Connected line identification presentation

The supplementary service which provides the calling party with the possibility to receive the identificationof the connected party

214 Connected line identification restriction

A supplementary service offered to the connected party to prevent presentation of the connected party’sISDN/MSISDN number to the calling party.

215 Malicious call identification (MCI)

The supplementary service which enables a mobile subscriber to request that the source of an incoming call isidentified and registered in the network.

216 Call forwarding unconditional (CFU)

The supplementary service which permits a called mobile subscriber to have the network send all incomingcalls, or just those associated with a specific Basic service, addressed to the called mobile subscriber’sdirectory number to another directory number. The ability of the served mobile subscriber to originate calls isunaffected. If this service is activated, calls are forwarded no matter what the condition of the termination.

217 Call forwarding mobile subscriber busy (CFB)

The supplementary service which permits a called mobile subscriber to have the network send all incoming





calls, or just those associated with a specific Basic service, addressed to the called mobile subscriber’sdirectory number and which meet mobile subscriber busy to another directory number. The ability of theserved mobile subscriber to originate calls is unaffected. If this service is activated, a call is forwarded only ifthe call meets mobile subscriber busy.

218 Call forwarding on no reply (CFNRy)

The supplementary service which permits a called mobile subscriber to have the network send all incomingcalls, or just those associated with a specific Basic service, addressed to the called mobile subscriber’sdirectory number and which meet no reply to another directory number. The ability of the served mobilesubscriber to originate calls is unaffected. If this service is activated, a call is forwarded only if the call meetsno reply.

219 Call forwarding on mobile subscriber not reachable (CFNRc)

The supplementary service which permits a called mobile subscriber to have the network send all incomingcalls, or just those associated with a specific basic service, addressed to the called mobile subscriber’sdirectory number, but which cannot be reached due to radio congestion, no paging response or because thesubscriber is not registered, to another directory number.

220 Call waiting (CW)

The supplementary service which offers a mobile subscriber the possibility to be notified of an incoming callwhilst the termination is in the busy state. Subsequently, the subscriber can either answer, reject, or ignorethe incoming call.

221 Completion of calls to busy subscribers (CCBS)

The supplementary service which allows a calling mobile subscriber, encountering a busy called destinationto have the call completed when the busy destination becomes not busy,without having to make a new callattempt.

222 Closed user group (CUG)

The supplementary service which provides the possibility for a group of subscribers, connected to the PLMNand/or the ISDN, to intercommunicate only amongst themselves and, if required, one or more subscribersmay be provided with incoming/outgoing access to subscribers outside this group.

223 Advice of charge (AoC)

The supplementary service which provides the possibility for a mobile user who pays for the use oftelecommunications services to receive charging information related to the used telecommunication services.





224 Call hold (HOLD)

The supplementary service which allows a served mobile subscriber to interrupt communication on anexisting call and then subsequently, if desired, re-establish communication. The traffic channel remainsassigned to the mobile subscriber after the communication is interrupted to allow the origination or possibletermination of other calls. The "retrieve" operation re-establishes communication on a channel.

225 Call transfer (CT)

The supplementary service which enables the served mobile subscriber to transfer an established incoming oroutgoing call to a third party. This service differs from the Call Forwarding supplementary service in thatCall Forwarding deals only with incoming calls that have not yet reached the "fully-established" state (i.e.,have an established end-to-end connection).

226 Three party service (3PTY)

The supplementary service which enables a mobile subscriber to establish a three party conversation. Amobile subscriber who is active on a call is able to hold that call, make an additional call to a third party,switch from one call to the other as required (privacy being provided between the two calls), and/or releaseone call and return to the other, or join the two calls together into a three-way conversation.

227 Conference call,add on (CONF)

The supplementary service which provides a mobile subscriber with the ability to have a multi-connectioncall, i.e. a simultaneous communication between more than two parties.

228 Barring of all outgoing calls(BAOC)

The supplementary service which makes it possible for a mobile subscriber to prevent all outgoing calls orjust those associated with a specific Basic service., The ability of the served mobile subscriber to receivecalls remains unaffected. The ability to set-up emergency calls remains unaffected .

229 Barring of outgoing international calls (BOIC)

The supplementary service which makes it possible for a mobile subscriber to prevent all outgoinginternational calls or just those associated with a specific basic service. Call set-up possibilities only exist tosubscribers of the PLMN(s) and the fixed network(s) of the country where the mobile subscriber is currentlylocated. The present PLMN may be the home PLMN or a visited PLMN respectively, the fixed network maybe that of the home PLMN country or that of a visited PLMN country. The ability of the served mobilesubscriber to receive calls remains unaffected. The ability to set-up emergency calls remains unaffected .





230 Barring of outgoing international calls except those directed to the home PLMNcountry (BOIC-exHC)

The supplementary service which makes it possible for a mobile subscriber to prevent all outgoinginternational calls except those directed to the home PLMN country, or just those associated with a specificbasic service. Call set-up possibilities only exist to subscribers of the PLMN(s) and the fixed network(s) ofthe country where the mobile subscriber is currently located or to subscribers of the home PLMN of theserved mobile subscriber and to subscribers of the fixed network(s) in the home PLMN country. The presentPLMN may be the home PLMN or a visited PLMN, respectively the fixed network may be that of the homePLMN country or that of a visited PLMN country. The ability of the served mobile subscriber to receive callsremains unaffected. The ability to set-up emergency calls remains unaffected.

231 Barring of all incoming calls (BAIC)

The supplementary service which makes it possible for a mobile subscriber to prevent all incoming calls orjust those associated with a specific basic service The ability of the served mobile subscriber to originate callsremains unaffected.

232 Barring of incoming calls when roaming outside the home PLMNcountry (BIC-Roam)

This service makes it possible for a mobile subscriber to prevent incoming calls or just those associated witha specific basic service only if the mobile subscriber roams outside the home PLMN country. The ability forthe served mobile subscriber to originate calls remains unaffected.

233 Mobile access hunting (MAH)

The supplementary service which enables incoming calls to be distributed over a group of accesses .

234 User-to-user signalling (UUS)

The supplementary service which allows a mobile subscriber to send/receive a limited amount or informationto/from another PLMN or ISDN subscriber over the signalling channel in association with a call to the othersubscriber.

235 Provision

An action to make a service available to a subscriber. The provision may be:— general: where the service is made available to all subscribers (subject to compatibility

restrictions enforced) without prior arrangements being made with the service provider.— prearranged: where the service is made available to an individual subscriber only after the

necessary arrangements have been made with the service provider.

236 Withdrawal

An action taken by the service provider to remove an available service from a subscriber’s access. Thewithdrawal may be:





— general : where the service is removed from all subscribers provided with the service.— specific : where the service is removed on an individual basis from subscribers provided with the

service.

237 Registration ((supplementary) service registration)

The programming by the service provider or subscriber of information to enable subsequent operation of aservice. The programming action involves input of specific supplementary information. For certain servicesthe registration procedure may cause activation whilst for others the service may already be in the activephase.

238 Erasure

The deletion by the service provider, the subscriber or the system of information stored against a particularservice by a previous registration(s).

239 Activation

An action taken by either the service provider, the subscriber or the system to enable a process to run as andwhen required by the service concerned. The time during which the process is activated is defined as theactive phase. During activation the service will be either "operative" or "quiescient" according to whether ornot the system is actually using the service, e.g. to forward a call or to apply call waiting indication.

240 Deactivation

An action taken by either the service provider, the subscriber or the system to terminate the process started atthe activation.

241 Invocation

An action to invoke the service required, taken by the subscriber (e.g. pressing a specific button) orautomatically by the network or terminal as a result of a particular condition (e.g. calling line identificationfor each incoming call)

242 Normal operation with successful; outcome

Description of the normal operation of the service, the normal served subscriber’s actions and the systemresponse. Decision points, timing and call progress signals would be some of the

subscriber.

243 Testing 02.04

The test procedure allows the subscriber to check whether or not the service is operating as desired. In somecases the use of the service is sufficient, for others a method of testing is included in the control procedure.(see GSM 02.04)





244 Interrogation ((supplementary) service interrogation)

The request by the subscriber to the PLMN to provide information about a specific supplementary service.This information can be requested by a— Status check.

The following values can be returned by the PLMN:– not supported– activated– deactivated

Not all values are applicable to all supplementary services.— Data check.

This interrogation function compares the data input by the subscriber during an interrogation procedurewith the information stored in the PLMN. The PLMN returns a standard tone, announcement orindications (e.g. "check is positive" or "check is negative").

— Data requestThis interrogation function enables the subscriber to obtain confirmation of input data. The PLMNreturns an appropriate announcement or indication (e.g. "the forwarded-to number is etc.").

245 Exceptional operation, unsuccessful; outcome

Abnormal situations not described in "normal operation with successful outcome". Procedures on time-out,unexpected signalling response and other such events would be defined.

246 Interworking considerations

Identification of subscriber perceptions when a call exits from an ISDN/PLMN to another CEPT specifiednetwork or enters an ISDN/PLMN from another CEPT specified network.

247 Interworking

The general term used to describe the inter-operation of networks, services, supplementary services etc.

248 Service interworking

The interworking required when the services at the calling and called terminals are different (e.g. a ShortMessage Service interworking with MHS access).

249 Supplementary service interworking

This the interworking between the same supplementary services in different networks..

250 Transparent support of services

Support of services where the network is unaware of the higher layer protocols, ie the higher layer protocolsare transparent to the PLMN. See also GSM 03.10





251 Non-transparent support of services

Support of services where the network makes use of knowledge of the higher layer protocols,ie some aspectsof the higher layer protocols are not transparent to the PLMN. See also GSM 03.10.

Version 1.0.0April 17, 1992 -- 11:35:08 [page.12]




2.3 Networks

301 Network, telecommunication network (305)

A set of nodes and links that provides connections between two or more defined points to facilitatetelecommunication between them.

302 Integrated services digital network (ISDN) (308)

An integrated services network that provides digital connections between user-network interfaces.)

303 Public land mobile network (PLMN)

A network, established and operated by an Administration or its licensed operator(s), for the specific purposeof providing land mobile communication services to the public. It provides communication possibilities formobile users. For communication between mobile and fixed users interworking with a fixed network isnecessary.

304 GSM public land mobile network (GSM PLMN)

A PLMN which complies with the GSM recommendations.

305 Home PLMN (HPLMN)

The PLMN where a subscription is held and therefore which contains the HLR of the subscriber.

306 Visited PLMN (VPLMN)

A PLMN whose services can be used temporarily, based on a subscription in another PLMN, the homePLMN.

307 Local PLMN (LPLMN)

The LPLMN is the HPLMN or VPLMN depending on the location of the MS at the time, and is the PLMNwith which the MS is registered via the radio interface.

308 GSM PLMN area (GPA)

The geographical area in which a GSM PLMN (see definitions 303, 304) provides telecommunicationservices according to the GSM Recommendations to mobile users. Note : CCITT Recommendation Q.1001does not contain a definition of a PLMN area.

309 GSM system area (GSA)

The group of GSM PLMN areas accessible by GSM mobile stations. Note : The system area according toCCITT Recommendation 0.1001 corresponds to the GSM System Area.

310 GSM service area 03.02

The area in which a mobile station can be reached by a fixed subscriber, without the subscriber’s knowledgeof the actual location of the mobile station within the area. A service area may include the areas served byseveral PLMNS. A service area may consist of one country, be a part of a country or comprise severalcountries.





311 GSM PLMN fixed infrastructure

The part of a GSM PLMN consisting of all fixed equipment,including the BSS’s,the MSC’s and associatedfunctional entities(such as VLR,HLR,AuC,EIR and IWF)..

312 Mobile-services switching centre (MSC)

The MSC performs the functions of switching, routing and control of the call and charging andaccounting.The MSC also controls the interworking with fixed networks.

313 Gateway MSC (GMSC)

An MSC that provides an entry point into the PLMN from another network or service. A gateway MSC isalso an Interrogating Node for incoming PLMN calls.

314 Connection (309)

A concatenation of transmission channels or telecommunication circuits, switching and other functional unitsset up to provide for the transfer of signals between two or more points in a telecommunication network, tosupport a single communication.

315 Digital connection (310)

A concatenation of digital transmission channels or digital telecommunication circuits, switching and otherfunctional units set up to provide for the transfer of digital signals between two or more points in atelecommunication network, to support a single communication.

316 Switched connection

A connection that is established by means of switching.

GSM note: In a GSM PLMN a switched connection only supports demand services since noreserved circuit services as defined in CCITT Recommendation I.112, 206 are foreseen.

317 GSM PLMN connection (314) 03.10

A connection that is established through a GSM PLMN between specified GSM PLMN reference points.

318 GSM PLMN connection type attribute

A specific characteristic of a GSM PLMN connection type whose values distinguish it from another GSMPLMN connection type.

319 GSM PLMN connection type,connection type (316) 03.10

A description of a set of GSM PLMN connections which have the same attributes.

320 GSM PLMN connection element,connection element (317)

A partition of a GSM PLMN connection,see GSM 03.10 for the basis of partitioning.

321 GSM PLMN connection element attribute

An attribute of a GSM PLMN connection element,eg information transfer rate.





322 Point to point GSM PLMN connection (320)

A GSM PLMN connection that is established between two specified GSM PLMN reference points.

323 Point to multipoint GSM PLMN connection (321)

A GSM PLMN connection that is established between a single specified GSM PLMN reference point, andmore than one other specified GSM PLMN reference points.

324 Public Data Network (PDN)

A network established and operated by an administration for the specific purpose of providing datatransmission services to the public. Circuit switched (CSPDN),packet switched (PSPDN) and leased circuitdata transmission services are feasible depending on national regulations. The Public Data Network maycarry other services.(Adapted from CCITT Rec. X.15)

325 Network interworking

The interworking required between two different networks (e.g. between a PLMN and ISDN, a GSM PLMNand a non-GSM PLMN, between two GSM PLMN) in order to provide an end to end connection.

326 Terminating Network

Network which in cooperation with a GSM PLMN provides telecommunication services between theirrespective users. Examples of terminating networks are the PSTN, the ISDN, PDNs, GSM PLMNs.

327 Interworking function (IWF)

A network functional entity which provides interworking (network interworking, service interworking,supplementary service interworking or signalling interworking). It may be a part of one or more logical orphysical entities in a GSM PLMN.

328 Interrogating Node (IN)

A switching node that interrogates a HLR, to route a call for an MS to the visited MSC.





2.4 Stations

401 Station

One or more transmitters or receivers or a combination of transmitters and receivers, including the accessoryequipment, necessary at one location for carrying on a radiocommunication service, or the radio astronomyservice. Each station shall be classified by the service in which it operates permanently or temporarily.(Quoted from the Radio Regulations Nx 58).

402 Mobile Station (MS)

A station in the mobile service intended to be used while in motion or during halts at unspecified points.(Quoted from the Radio Regulations Nx 65).

403 Land Station

A station in the mobile service not intended to be used while in motion. (Quoted from the Radio RegulationsNx 67).

404 Base Station (BS)

A land station in the land mobile service. (Quoted from the Radio Regulations No 68).

405 Land Mobile Station

A mobile station in the land mobile service capable of surface movement within the geographical limits of acountry or continent. (Quoted from the Radio Regulations Nx 69).

406 GSM Mobile Station (GSM MS)

Equipment intended to access a set of GSM PLMN telecommunication services. Services may be accessedwhile the equipment capable of surface movement within the GSM system area is in motion or during halts atunspecified points. Note : This definition has been adapted from the definitions of a Mobile Station and aLand Mobile Station in the Radio Regulations.

407 Mobile Equipment (ME)

The ME is the Mobile Station (MS) without the SIM.

408 Base Station System (BSS)

The system of base station equipment (transceivers, controllers, etc..) which is viewed by the MSC through asingle interface as defined by the GSM 08 0x series of recommendations, as being the entity responsible forcommunicating with Mobile Stations in a certain area. The radio equipment of a BSS may cover one or morecells. A BSS may consist of one or more base stations. If an internal interface according to the GSM 08.5xseries at recommendations is implemented, then the BSS shall consist of one Base Station Controller (BSC)and several Base Transceiver Stations (BTSs). The functionality is described in Recommendation GSM08.02.

409 Base Station Controller (BSC)

A network component in the PLMN with the functions for control of one or more Base Transceiver Stations(BTSs).





410 Base Transceiver Station (BTS)

A network component which serves one cell, and is controlled by a Base Station Controller. The BTScontains one or more Transceivers (TRXs).

411 Transceiver (TRX)

A network component which can serve full duplex communication on 8 full-rate traffic channels according torecommendation GSM 05.02. If Slow Frequency Hopping SFH is not used, then the TRX serves thecommunication on one RF carrier.





2.5 Access

501 User access. user network access (402)

The means by which a user is connected to a telecommunication network in order to use the services and/orfacilities of that network.

502 Interface (408)

The common boundary between two associated systems.

503 Service Access Point (SAP)

In the reference model for Open System Interconnection, Service Access Points (SAPs)of a layer are definedas gates through which services are offerred to an adjacent higher layer.

504 Physical interface (411)

The interface between two equipments.

505 Access capability. GSM PLMN access capability (416)

The number and type of the access channels at a GSM PLMN access interface that are actually available fortelecommunication purposes.

506 Terminal Equipment (TE) (417)

Equipment that provides the functions necessary for the operation of the access protocols by the user.

507 Terminal adaptor (TA)

A physical entity in the MS providing terminal adaptation functions. (GSM 04.02)

508 Mobile Termination (MT)

The part of the Mobile Station which terminates the radio transmission to and from the network and adaptsterminal equipment (TE) capabilities to those of the radio transmission.

509 Reference point (420)

A conceptual point at the conjunction of two non-overlapping functional groups.

510 Reference configuration (421)

A combination of functional groups and reference points that shows possible network arrangements.

511 Multipoint access (422)

User access in which more than one terminal equipment is supported by a single mobile termination.

512 Functional group, functional grouping (419)

A set of functions that may be performed by a single equipment.

513 Terminal adaptation function(TAF)

The terminal adaptation function is a functional entity associated with an MS. The TAF provides thefunctionality necessary to permit interworking between an MT and Terminal equipment(TE). The function ofthe TAF depends on the service and the type of TE. The TAF is required to convert the





protocols provided by the MT to those used by the TE. The terminal adaptation functions are described inGSM 07.01,07.02 and 07.03.

514 Direct access

Interworking to a Private Telecommunciations Network via a dedicated link.

515 Mobile Originated (MO)

Call or short message originated from the Mobile Station.

516 Mobile Terminated (MT)

Call or short message intended to be delivered to the Mobile Station.





2.6 Location and handover

601 Location register (LR) 03.01

The functional unit in which the location information is stored.

602 Location information 03.01

The information, indicating where a mobile station is located in the system area.

603 Location registration 03.01

The function whereby PLMNs keep track of the location information of Mobile Stations located in thesystem area.

604 Home location register (HLR) 03.01

The location register where the current location and all subscriber parameters of a mobile station arepermanently stored.

605 Visited location register (VLR) 03.01

The location register where all relevant parameters concerning a mobile station are stored as long as themobile station is in a location area controlled by this register.

606 Location area Q.9/ Q.1001

An area in which a mobile station may move freely without up-dating the location register. A location areamay comprise one or several base station areas.

607 MSC area Q.1001, 03.02

The part of the PLMN covered by an MSC. An MSC area may consist of one or several location areas.

608 Base station area

The part of the GSM area to which a base station gives service.

609 Paging, Paging procedure 04.08

The procedure by which a GSM PLMN fixed infrastructure attempts to reach a Mobile Station within itslocation area , before any other network-initiated procedure can take place.

610 Location area identification 03.03

The information indicating the location area in which a cell is located.

611 Deregistration, location deregistration

The updating of a location register by removing location information.

612 Location updating procedure 09.02

The procedure by which location register updating takes place.

613 Location cancellation procedure 03.01

The procedure by which the location information is removed from a location register.





614 Location information requested procedure 03.01

The procedure by which a VLR enquires whether or not a MS should be kept in the register.

615 Location information retrieval procedure 03.01

The procedure by which the home location register obtains information on which of its mobile stations areregistered with a visited location register.

616 Reset procedure

The procedure for recovery of information for a location register after restart.

617 Restart (Restart procedure)

The procedure to recover the information in a location register after the location information is lost due to afailure.

618 Restoration, Restoration procedure

The procedure to recover the information in a location register, after the location information is lost due to afailure. It consists of a restart procedure, after which some mechanisms are provided to keep track of thereliability of each element in memory.

619 Handover

The action of switching a call in progress from one radio channel to another radio channel. Handover is usedto allow established calls to continue by switching them to another radio resource, e.g. when mobile stationsmove from one base station area to another. Handover may take place between the following GSM entities;timeslot ,RF carrier, cell, base station, BSS, MSC. The prefixes "inter" and "intra" are used to describe thetype of handover according to context, e.g. inter-cell handover. These entities are listed in nested order suchthat "inter-BSS handover" is implicitly inter -BS, inter-cell, etc. Additionally, the words "internal" or"external" may prefix the term intra-BSS handover with the following meanings "Internal intra-BSShandover" is an intra-BSS handover which takes place without reference to the MSC (although the MSC willbe informed on completion). "External intra-BSS handover" is an intra-BSS handover which is controlled byan MSC.

620 Basic handover procedure 03.09

A procedure in which a call is handed over from the MSC under which the call was originated to anotherMSC.

621 Subsequent handover procedure 03.09

A procedure in which a call is handed over from an MSC under which the call was not originated to anotherMSC.

622 Cell

The area of radio coverage locally defined as seen by the Mobile Station with a Base Station Identity Code(BSIC) and uniquely defined as seen by the network with a cell global Identification.





2.7 Identity and Security

701 Algorithm A3

Cryptographic algorithm that produces SRES, using RAND AND Ki.

702 Algorithm A5

Cryptographic algorithm that produces ciphertext out of cleartext, using Kc.

703 Algorithm A8

Cryptographic algorithm that produces Kc using RAND and Ki.

704 Authentication

The corroboration that a peer entity is the one claimed.

705 Authentication centre (AUC)

Component of the fixed part of the PLMN which contains subscriber authentication keys (Ki) and generatessecurity related parameters (RAND, SRES, Kc) - depending on implementation.

706 Base station identity code (BSIC)

A block of code, consisting of the PLMN colour code and a base station colour code. One Base Station canhave several Base Station Colour Codes.

707 Cell Global Identification

A block of code which uniquely identifies a cell within all GSM PLMNs. It consists of the LAI and CI.

708 Cell Identity (CI)

A block of code which identifies a cell within a location area.

709 Reserved

710 Cipherkey

A sequence of symbols that controls the operation of encipherment and decipherment.

711 Cipherkey setting

Mutual agreement between the Mobile Station and the fixed part of the system upon a common cipherkey(Kc) to be used in a subsequent encipherment/ decipherment process.

712 Ciphertext

Unintelligible data produced through the use of encipherment.

713 Cryptographic algorithm [ cryptological algorithm]

Mathematical method used in encipherment and decipherment or in non-reversible encipherment.

714 Decipherment

The transformation by cryptographic techniques to produce plaintext from ciphertext.





715 Encipherment

Transformation by cryptographic techniques to produce ciphertext from plaintext.

716 International mobile station equipment identity (IMEI)

Uniquely identifies the mobile station as a piece or assembly of equipment.

717 International mobile subscriber identity (IMSI)

Uniquely identifies the subscription. It can serve as a key to derive subscriber information such as directorynumber(s) from the HLR.

718 Key setting

See cipherkey setting.

719 Mobile station international ISDN number(MSISDN) 03.03

Uniquely defines the mobile station as an ISDN terminal. It consists of three parts; the country code (CC), thenational destination code (NDC) and the subscriber number (SN).

720 Mobile Station Roaming Number (MSRN) 03.03

A code which is allocated to a mobile station when registered with a VLR for the purpose of routing calls tothe MSC in which area the Mobile Station is located.1. The MSRN is used by the home location register forrerouting calls to the mobile station.

721 Personal Identification Number (PIN)

Confidential information which may be used in the authentication between subscriber and SIM to corroboratethat the subscriber is the one claimed.

722 Plaintext

Unciphered Data.

723 RAND

Random number to be used as challenge in a challenge response protocol.

724 Random number

Non-predictable number.

725 Security feature

Security features protect

• the access to the mobile services

• any relevant item from being disclosed on the radio path, mainly in order to ensure the privacy of userrelated information.

726 Signed Response (SRES)

Response to a challenge in the challenge response protocol.





727 Reserved

728 Stream cipher

Bit by bit binary addition of plaintext bitstream and cipherkey bitstream.

729 Subscriber authentication key

Subscriber individual confidential information used in authentication and in the cipher key generation process

730 Subscriber identity authentication

The corroboration by the fixed part of the PLMN that the subscriber identity (IMSI, TMSI), transferred by themobile subscriber within the authentication procedure at the radiopath, is the one claimed.

731 Subscriber identity confidentiality

The property that the subscriber identity (IMSI) is not made available or disclosed on the radio interface.

732 Subscriber Identity Module (SIM)

Removable module which is inserted into a Mobile Equipment; it is considered as part of the Mobile Station.It contains security related information (IMSI, Ki, PIN), other subscriber related information and theAlgorithms A3/A8.

733 Temporary Mobile Subscriber Identity (TMSI) 03.03

A unique identity temporarily allocated to visiting mobile subscribers in order to support the subscriberidentity confidentiality service.

734 Local Mobile Station Identity(LMSI)

A unique identity temporarily allocated to visiting mobile subscribers in order to speed up the search forsubscriber data in the VLR, when the MSRN allocation is done on a per call basis (see definition 720)





2.8 Administrative and commercial definitions

801 CEPT Administration

The national administration which has signed the "Arrangement instituant la Confrence Europenne desAdministrations des Postes et des Telcommunications".

802 GSM PLMN operator

An administration or its licensed operator(s) which provides a GSM PLMN and its telecommunicationservices.

803 Service Provider

The organisation through which the subscriber obtains GSM telecommunication services. This may be anetwork operator or possibly a separate body.

804 Subscription

The subscription permits participation in telecommunication services (basic telecommunication services andthose supplementary services for which it is necessary).

805 Customer

The customer is the individual or entity who, or which, obtains a service from a GSM PLMN operator or anauthorized agent and is responsible for payment of all charges and rentals due. Note : This definition isadapted from CCITT Rec. D.000.

806 Subscriber

The definition of this term is identical with that of the term "customer" under 805.

807 User

The user is the individual or entity designated by the customer, individually or by class, as having access tothe service and having such authorization, individually or by class, as may be required by the GSM PLMNoperator or an authorized agent concerned. Note : This definition is adapted from CCITT Rec. D.000.

808 Collection charge

The collection charge is the charge in its national currency collected by a GSM PLMN operator or anauthorized agent from its customers for the use of the service. The establishment of the collection charge is anational matter. Note : This definition is adapted from CCITT Rec. D.000.

809 Network access charge

Part of the collection charge, intended to cover cost of service which is not dependent on the actual use ofnetworks/telecommunications services. It may consist of an initial fee and a subscription fee.

810 Network utilization charge

Part of the collection charge which is intended to cover use of the networks/telecommunications services. Thecharge is registered on a per case basis.





811 Rental

Payment(s) due to a GSM PLMN operator or an authorized agent for the access to certain services for thedesignated periods. Note : This definition is adapted from CCITT Rec. D.000.

812 NET (Norme Europeenne de Telecommunications)

An approved conformity specification recommendation of the CEPT or part or parts hereof, which thesignatories of the Memorandum of Understanding (MoU) on European Telecommunications Standards forterminal equipment (Nov. 15; 1985). adopted in accordance with the procedures set down in that MoU. Itincludes, where appropriate, requirements made necessary in a given country by historical networkpeculiarities or established national provisions concerning the use of radio frequencies.

813 Conformity specification

A document giving a full description of the technical characteristics of the relevant telecommunicationsterminal equipment (such as safety, technical parameters, functions and procedures and service requirements)together with a precise definition of the test and test methods enabling the conformity of the equipment withthe prescribed technical characteristics to be verified.

814 Approved testing laboratory

A laboratory which has been accredited by the appropriate Administration or an accrediting body recognizedas competent in its country, according to Rec. T/G 01-01, and which is approved by that Administration orState as competent for conducting conformity tests on telecommunications terminal equipment.

815 Certificate of conformity

A certificate, issued in accordance with the Recommendation T/SF 48, which indicates that atelecommunications terminal equipment has been tested by an approved testing laboratory, using appropriatetest methods, and is in conformity with defined standards, such as NETs, or parts thereof.

816 Certifying body

A body which determines whether a test report from an approved testing laboratory shows that atelecommunications terminal equipment has been tested using appropriate test methods and is in conformitywith defined standards. If so, the body issues a certificate of conformity. Note : This body may be theappropriate national authority, or the national Approval Authority such as an independent body or theapproved testing laboratory which conducted the tests.





2.9 Operations and maintenance

901 Controlled maintenance CCITT G.106, Nx 4123/CEPT T/CS 10-13

A method to sustain (or sustaining) a desired"quality of service" (network technical performance) bysystematic application of analysis techniques using centralized supervisory facilities and /or sampling tominimize "preventive maintenance" and to reduce "corrective maintenance".

902 Corrective maintenance ; repair CCITT G.106,Nx 4105/CEPT T/CS 10-13

The "maintenance" carried out after "fault" (failure) recognition" and intended to restore an "item" to a statein which it can perform a (its) "required function".

903 Data Communication Network (DCN) CCITT M 2x

A DCN connects Network Elements (NEs) with internal mediation functions or mediation devices (MOs) tothe Operations Systems (0Ss). (The reference model for open systems interconnection - CCITT Rec. X. 200 -should be followed). Note: In general, a DCN does not provide all the data communication functions for aTMN. Data communication links may be required as part of a Local Communication Network.

904 Fault GSM 12.00

The inability of an "item" to perform a "required function".

905 Failure GSM 12.00

The termination of the ability of an "item" to perform a "required function".

906 Indenture level CCITT G.106, Nx4119

A level of subdivision of an item from the point of view of a "maintenance action". Note 1: examples ofindenture levels could be a subsystem, a circuit board, a component. Note 2: the indenture level depends onthe complexity of the item’s construction, the accessibility to subitems, skill level of maintenance personnel,test equipment facilities, safety considerations, etc.

907 Local Communication Network (LCN) CCITT M. 2x

A LCN connects NEs to MDs or MDs to MDs within a telecommunication centre. However, for practicalreasons, a LCN may connect remote NEs to local MDs.

908 Maintenance CCITT G.106,Nx 4103 CEPT T/CS 10-13

The combination of all technical and corresponding administrative actions including supervision actions,intended to retain an "item" in, or restore it to, a state in which it can perform a "required function".





909 Maintenance entity (ME) CCITT 6. 106,Nx 4130‘

A sub-item of a given "item" defined with the intention that an alarm caused by a "fault" in that sub-item willbe unambiguously referrable to the sub-item. Note The definitions of CCITT and CEPT seem to besomewhat divergent. Since CEPT Recommendations are referring to CCITT Recommendation G.106, andthe CCITT definition is more precise, the CCITT view shall be applied.

910 Mediation CCITT M. 2x‘

A process that routes and/or acts on information passing between NEs and OSs via DCN. Mediation can beshared among NE (s) and/or OS (s). The processes that can form mediation can be classified into followingfive general process categories

1 . Communication control

2 . Protocol conversion and data handling

3 . Communication (passing) of primitive functions

4 . Processes involving decision making

5 . Data storage.

911 Network administration GSM 12.00‘

(not in the sense of a body) Network administration is the network related part of the Operator’s ServiceProvider’s overall administration and any organization, non-technical action to provide or to help to provideservices of a telecommunication network.

912 Network Management (NM) GSM 12.00‘

NM is all activities which control, monitor and record the use and the performance of resources of atelecommunication network in order to provide telecommunication services to customers/users at a certainlevel of quality.

913 Network Management Centre (NMC) GSM 12.01/12.07‘

The NMC node of the GSM TMN provides global and centralised PLMN monitoring and control, by being atthe top of the TMN hierarchy and linked to subordinate OMC nodes.

914 Operations CCITT G.106,Nx1012‘

Combination of all technical and corresponding administrative actions intended so that any "item" canperform a "required function", recognizing necessary adaptation to changes in external conditions. (Note: byexternal conditions are understood, for example, service demand and environmental conditions).

915 Operations and Maintenance Centre (OMC) GSM 12.01/12.07‘

The OMC node of the GSM TMN provides dynamic O&M monitoring and control of the PLMN nodesoperating in the geographical area controlled by the specific OMC.

916 Operations System (OS) CCITT M.2x‘

There are, at least, three functional types of OSs, i.e. basic, network, and services





• Basic OSs perform TMN application functions related to Network Elements (NEs) located in specificregions.

• Network OSs cover the realization of network based TMN application functions by communicatingwith basic OSs.

• Service OSs perform specific application functions for managing and individual service.

Basic OSs and Network OSs share infrastructural aspects of the telecommunication network. Service OSs areconcerned with service aspects of one or more telecommunication networks.

917 Preventive maintenance CCITT G.106,Nx4104

The "maintenance" carried out at predetermined intervals or according (corresponding) to prescribed criteriaand intended to reduce the "probability" of "failure" or the (performance) degradation of the functioning of an"item".

918 Performance Management GSM 12.07

Performance Management of PLMN implies the maintaining of quality of service without sacrificing the setfinancial objectives of the Operator.

919 Resource Management GSM 12.00

Resource Management (by planning functions, procurement etc.) provides the network resources (active andpassive telecommunication equipment) and the NM resources.

920 Security Management GSM 12.03

Security Management is the control and distribution of security-relevant information to various users andsystems for

• use in providing security services,

• reporting on security services and mechanisms,

• reporting on security-relevant events that have occurred.

921 System change control GSM 12.06

The mechanism which assumes the satisfactory function of the programmes controlling the system alsoensures that programme change and updating are satisfactorily carried out.

922 TMN Standard Interfaces CCITT M. 2x

The standard interfaces which provide for the interconnection of NEs, 0Ss, MDs and WSs through the DCNor LCN. Note: This requires compatible communication protocols and a compatible data representationmethod for the messages, including compatible generic message definitions for TMN application functions.

923 Work Station (WS) GSM 12.00

The remote device via which O&M personnel executes input and output transactions for NM purposes.

924 Administration Centre (ADC)

The ADC node of the TMN provides for PLMN Operator-specific requirements in the administration andcommercial areas.





925 Telecommunications Management Network (TMN)

The implementation of the Network Management functionality required for the PLMN is in terms of physicalentities, the full ste of which constitutes the TMN





2.10 Expressions related to the radiosubsystem

1001 Absolute RF Channel Number (ARFCN) 05.05

An integer which defines the absolute RF channel number.

1002 Active mode 05.08

The state of a MS when processing a call.

1003 Active part of timeslot 05.02

Identical with burst.

1004 Adaptive Frame Alignment 05.08

Means of ensuring that the timeslots received at the BS from active MSs at different distances from the BSare in time alignment. Transmit timeslot advance period in the MS necessary to ensure this. The value can beassessed by measuring the "roundtrip delay"; this depends on the distance of the MS from the serving BS.

1005 BCCH allocation (BA) 05.08

The radio frequency channels allocated in a cell for BCCH transmission.

1006 Bit number (BN) 05.02

Number which identifies the position of a particular bit period within a timeslot.

1007 Burst 05.02

A period of modulated carrier less than one timeslot. The physical content of a timeslot.

1008 Call Release 05.08

Forced disconnection after a fixed period when the ACCH data is no longer decoded correctly.

1009 Cell allocation 05.02

The radio frequency channels allocated to a particular cell.

1010 Cell Coverage Area 03.30

Area within which a defined quality of reception is provided. The planned radio coverage of a cell.

1011 Channel 05.02

A means of one-way transmission. A defined sequence of periods (e.g. timeslots) in a TDMA system; adefined frequency band in an FDMA system; a defined sequence of periods and frequency bands in afrequency hopped system.

1012 Class IA. lB. II 05.03/05.04

The classification of speech encoder bits depending on the degree of protection needed. Class IA and class IBbits have protection, while Class II bits have no protection. Error detection is performed on class IA bits.

1013 Control Channels (CCH) 05.01

Channels which carry system management messages.





1014 Current Serving BS 05.10

BS on one of whose channels (TCH, DCCH, or CCCH) the MS is currently operating.

1015 Discontinuous Reception (DRX) 05.08

Means of saving battery power (e.g. in HPUs) by periodically and automatically switching the MS receiveron and off.

1016 Discontinuous Transmission (DTX) 05.08

Means of saving battery power (e.g. in HPUs) and reducing interference by automatically switching thetransmitter off when no speech or data are to be sent.

1017 Downlink 05.02.

Physical link from the BS towards the MS (BS transmits, MS receives).

1018 Dummy bits 05.04

Internal states of the modulator before and after a burst.

1019 Dummy Burst (DB) 05.02

A period of carrier less than one timeslot whose modulation is a defined sequence that carries no usefulinformation. Means of filling a timeslot with an RF signal when no information is to be delivered to achannel.

1020 Ec/No

Ratio of energy per modulating bit to the noise spectral density.

1021 Frame number (FN) 05.02

Identifies the position of a particular TDMA time-frame within a hyperframe.

1022 Frequency correction burst (FB) 05.02

Period of RF carrier less than one timeslot whose modulation bit stream allows frequency correction to beperformed easily within a mobile station.

1023 Guard Period 05.05

Period at beginning and end of timeslot during which MS transmission is attenuated.

1024 Handover 05.08

Change of dedicated channel during call.

1025 Handover Access Burst 05.08

Access burst used during handover.

1026 Handover Execution 05.08/03.09

Signalling message sequence that causes the MS to continue the call in another (predetermined) cell.

1027 Handover Execution Interval 05.08

Period of time between consecutive handover execution commands.





1028 Handover Margin 05.08

Hysteresis factor that minimises repetitive handovers between adjacent cells. Means to affect the trafficdistribution between cells.

1029 Handover Strategy 05.08

Procedure defined by an algorithm that prescribes how handover shall be carried out e.g. handover to a cellwhich offers better signal strength or to a cell which allows communication with less power.

1030 Hyperframe 05.02

A hyperframe consists of 2048 superframes (see definition 1055) It is the longest recurrent time period of theframe structure (12 533.76s).

1031 Idle Mode 05.08

State of an MS not actively processing a call.

1032 Inactive part of timeslot 05.02

Identical with guard period.

1033 Inter-Cell Handover 05.08

Handover between cells. Change of serving cell.

1034 Intra-Cell Handover 05.08

Handover between different RF carriers or different timeslots of the same RF carrier within one cell.

1035 Logical channels 05.02

Two classes of logical channels are defined, control channels (CCH) which carry system managementmessages and traffic channels (TCH) which carry users’ speech or data.

1036 Mobile allocation (MA) 05.02

The radio frequency channels allocated to a MS for use in its hopping sequence.

1037 Multiframe (Multiple time-frame) 05.01

Two types of multiframe are defined in the system: a 26-frame multiframe with a period of 120ms and a 51-frame multiframe with a period of 3060/13ms.

1038 Multiple timeframe

See multiframe.

1039 Network Directed Criteria 05.08

Handover criteria originating from network management requirements, e.g. traffic, precedence requests etc...

1040 Network Management Requirements 05.08

See network directed criteria.

1041 Normal Burst (NB) 05.02

A period of modulated carrier less than a timeslot.





1042 Peak power

Measure of the maximum RF power when averaged over one radio frequency cycle, during the useful part ofthe burst.

1043 Power Class (of MS) 05.05

Class of maximum output power to which a MS belongs; e.g. handheld portable, mobile. Defined by themaximum peak power that can be output by a MS. Five power classes are defined.

1044 Power control Level 05.05

Peak power level (less than or equal to the maximum peak power corresponding to the power class) that aMS outputs on command from the BS of the serving cell.

1045 Power Control Message 05.08

Message that controls the MS transmitted RF power level (see MS_TXPWR_REQUEST).

1046 Quarter Bit Number 05.10

Timing of quarter bit periods (12/13 us) within a timeslot.

1047 Radiofrequency channel (RFCH)

A partition of the system RF spectrum allocation with a defined bandwidth and centre frequency.

1048 Radio Sub-System Criteria 05.08

Criteria used in the handover and transmitted RF power control processes (e.g. signal strength, signal quality,absolute MS-BS distance).

1049 Radio Sub-System Directed Handover 05.08

Change of channel during a call because of either degradation of quality of the current serving channel or theavailability of another channel which can allow communication at a lower transmitted RF power, or toprevent a MS grossly exceeding the planned cell area.

1050 Roundtrip Delay 05.08

Time period between transmit and receive instant of a timeslot in the BS, determined by the responsebehaviour of the MS and the MS-BS distance.

1051 Serving BS 05.08

BS with which the MS is currently communicating.

1052 Serving Cell 05.08

Cell containing the serving BS.

1053 SID-frame 06.31

Frame which carries the averaged background noise information

1054 Sub-channel number (SCN) 05.02

One of the parameters defining a particular physical channel in a BS.





1055 Superframe 05.01

A superframe is 51 traffic/associated control multiframes or 26 broadcast/common controlmultiframes.(period 6.12s).

1056 Synchronization burst (SB) 05.02

Period of RF carrier less than one timeslot whose modulation bit stream carries information for the MS tosynchronize its time-frame start to that of the received signal.

1057 Tail bits 05.03/05.04

Known bits that are added at the end of the information stream to allow use of a convolutional code to build a(non-systematic) block code while preserving the minimum distance properties.

1058 TDMA Frame Number 05.02

The number of a particular TDMA frame in the cyclic TDMA frame numbering range (2715647).

1059 Timebase Counters 05.10

A set of counters which determine the timing state of signals transmitted by a BS or MS.

1060 Time-frame 05.01

The repetition period of the (8) timeslots of a particular RF channel (period 60/13 = 4.62 ms approx.).This isreferred to as a frame in the definition of multiframes.

1061 Timeslot 05.01

One of a number of periods in a time-frame (period 15/26ms). Physical channel in a TDMA system.

1062 Timing Advance 05.10

A signal sent by the BS to the MS. It enables the MS to advance the timing of its transmissions to the BS soas to compensate for propagation delay.

1063 Timeslot Number (TN) 05.02

Identifies a particular timeslot within a TDMA frame frame.

1064 Traffic channels 05.02

Channels which carry users’ speech or data.

1065 Training sequence 05.02

Sequence of modulating bits employed to facilitate timing recovery and channel equalisation in the receiver.

1066 Training sequence code 05.02

Parameter used to select one of a number of training sequences.

1067 Uplink 05.02

Physical link from MS towards BS (MS transmits, BS receives)

1068 Useful part of timeslot 05.04

That part of the burst used by the demodulator; differs from the full burst because of the 1/2 bit shift of the Iand Q parts of the GMSK signal.





1069 Voice activity detection (VAD) 05.03/05.04

A process used to identify presence or absence of speech data bits.This is used along with DTX (seedefinition 1016)





2.11 Miscellaneous

1101 Mobile Station Feature

A MS feature is a function or a piece of equipment which directly relates to the man-machine operation of theMS. Three categories of MS features are distinguished: basic, supplementary and additional features.

1102 Queuing

The procedure in which calls, originating from a MS or terminating in a MS are kept pending for reasons ofcongestion or when the called party is occupied.

1103 Off-air-call-set-up (OACSU)

The procedure in which a telecommunication connection is being established whilst the r.f. link between theMS and the BS is not occupied.

1104 Mobile Application Part (MAP) 09.01/03.01

The internetworking signalling between MSCs and LRs and EIRs. A part of CCITT Signalling System No. 7

1105 Signalling Interworking

Signalling Interworking is the function required to connect the signalling protocols used in a GSM PLMN tothose used in the appropriate fixed network.

1106 Layer 2 relay (L2R)

A function of an MS and IWF that adapts a user’s known layer2 protocol onto RLP for transmission over theGSM radio interface. See also GSM 07.01,07.02 and 07.03.

1107 Radio Link Protocol (RLP)

An Automatic Repeat reQuest (ARQ) protocol used to reliably transfer user data between an MS andIWF.See also GSM 04.22





3. ABBREVIATIONS AND ACRONYMS

A3 see Algorithm A3 (701)A5 see Algorithm A5 (702)A8 see Algorithm A8 (703)AB Access BurstACCH Associated Control ChannelACM Address Complete MessageACU Antenna Combining UnitADC ADministration Centre (924)AEF Additional Elementary FunctionsAGCH Access Grant CHannelAOC Advice Of Charge (223)ARFCN Absolute Radio Frequency Channel Number (1001)ARQ Automatic Request for Retransmission (1007)AUC Authentication Centre (705)AUT(H) Authentication (704)BA BCCH Allocation (1005)BAIC Barring of All Incoming Calls (231)BAOC Barring of All Outgoing Calls (228)BCC Base Transceiver Station (BTS) Colour Code 05.02BCCH Broadcast Control ChannelBCCH_FREQ_NCELL Frequency of the RF carrier on which the BCCH of a neighbouring cell

is transmitted. 05.08BCD Binary Coded DecimalBCU (See 08.56)BIC-Roam Barring of Incoming Calls when Roaming Outside the Home PLMN

Country (232)Bm Full-rate traffic channelBN Bit Number (1006)BNHO Barring all outgoing calls except those to Home PLMNBOIC Barring of Outgoing International Calls (229)BOIC-exHC Barring of Outgoing international Calls except those directed to the

Home PLMN Country (230)BS Base Station (404)BS_BCCH_SDCCH_C0MB Logical variable that indicates the combination of dedicated and

associated control channels on the same physical channel 05.02





BS_CC_CHANS Number of basic physical channels supporting common controlchannels 05.02

BS_G_BLKS_RES Number of blocks on each common control channel reserved for accessgrant messages 05.02

BS_PA_MFRMS Number of multiframes between two transmissions of the same pagingmessage to MSs of the same paging group 05.02

BSC Base Station Controller (409) 05.02BSIC Base Transceiver Station Identity Code (706) 05.02BSIC-NCELL BSIC of an adjacent cell 05.08BSS Base Station System (408)BTS Base Transceiver Station (410)C ConditionalCA Cell AllocationCA_BAND_NUMB Number of the frequency band that contains the cell allocation 05.05CBCH Cell Broadcast CHannel 05.02CC Country CodeCCBS Completion of Calls to Busy Subscribers (221)CCCH_GROUP Group of MSs in idle modeCCH Control CHannel (1013)CCPE Control Channel Protocol EntityCELL-BAR-ACCESS Cell Access BarredCELL_RESELECT_HYSTERESIS RXLEV Hysteresis required for Cell ReselectionCFB Call Forwarding on mobile subscriber Busy (217)CFNRc Call Forwarding on MS Not REAchable (219)CFNRy Call Forwarding on No Reply (218)CFU Call Forwarding Unconditional (216)CI Cell Identity (708)CLIP Calling Line Identification Presentation (211)CLIR Calling Line Identification Restriction (212)CMD CommandCOLI Connect Line IdentityCOLP Connected Line Identification Presentation (213)COLR Connected Line identification Restriction (214)COM CompleteCONF Conference Call,add on (227)CONN ConnectCRE Call RE-establishment procedureCSPDN Circuit Switched Public Data Network(324)CT Channel TesterCT Call Transfer (225)CUG Closed User Group (222)CW Call Waiting (220)





DB Dummy Burst (1019)DCCH Dedicated Control ChannelDCF Data Communication FunctionDCN Data Communication Network (903)DET DetachDISC DISConnectDL Data Link (layer)DLCI Data Link Connection IdentifierDLD Data Link DiscriminatorDm Control Channel (ISDN terminology applied to mobile service)DP Dialled PulseDRX Discontinuous Reception (Mechanism) (1015)DTAP Direct Transfer Application PartDTE Data Terminal EquipmentDTMF Dual Tone Multi-Frequency (signalling)DTX Discontinuous Transmission (Mechanism) (1016)EA External AlarmsEc/No Ratio of energy per modulating bit to the noise spectral density (1020)EIR Equipment Identity RegisterERR ERRorFA Full AllocationFACCH Fast ACCHFACCH/F Full rate Fast Associated Control ChannelFACCH/H Half rate Fast Associated Control ChannelFB Frequency correction Burst (1022)FCCH Frequency Correction CHannelFEC Forward Error CorrectionFN Frame Number (1021)GMSC Gateway Mobile Services Switching Centre (313)GPA GSM PLMN area (308)GSA GSM System Area (309)GSM Groupe Special MobileGSM MS GSM Mobile Station (406)GSM PLMN GSM Public Land Mobile Network (304)





HANDO HandoverHDLC High Level Data Link ControlHLR Home Location Register (604)HO_MARGIN SDL Message name for Handover MarginHOLD Call Hold (Supplementary Service) (224)HPLMN Home PLMN (305)HPU Hand Portable UnitHSN Hopping Sequence Number 05.02I Information (frames)IAM Initial Address MessageICB Incoming Calls BarredID IdentificationIDN Integrated Digital NetworkIE Signalling Information ElementIMEI International Mobile station Equipment Identity (716)IMSI International Mobile Subscriber Identity (717)IN Interrogating Node (328)INU Interworking UnitISDN Integrated Services Digital Network (302)IWF Inter Working Function (327)K Constraint Length of the Convolutional CodeKc Cipher KeyKi see "subscriber authentication key" (729)L2R Layer 2 Relay (1106)LAC Location Area CodeLAI Location Area Identity 05.08LAN Local Area NetworkLAPDm Link Access Protocol on the Dm channelLCN Local Communication Network (908)LE Local ExchangeLm Traffic channel with capacity lower than BmLPLMN Local PLMN (307)LR Location Register (601)M MandatorMA Mobile Allocation (1036)MACN Mobile Allocation Channel NumberMAF Mobile Additional Function





MAH Mobile Access Hunting (233)MAI Mobile Allocation Index 05.02MAIO Mobile Allocation Index Offset 05.02MAP Mobile Application Part (1104)MCC Mobile Country CodeMCI Malicious Cell Identification (215)MD Mediation DeviceMDL (mobile) Management (entity) - Data Link (layer)ME Maintenance Entity (909)ME Mobile Equipment (407)MEF Maintenance Entity FunctionMIC Mobile Interface ControllerMM Man MachineMME Mobile Management EntityMMI Man Machine InterfaceMNC Mobile Network CodeMO Mobile Originated (515)MPH (mobile) Management (entity) - PHysical (layer) [primitive]MS Mobile Station (402)MS_PWR_CLASS MS PoWer Class. Parameter defining the power class of an MS

expressed in the same way as the R parameters 05.08MS_RANGE_MAX Mobile Station Range Maximum. Handover criterion to determine

serving cellMS_RXLEV_L Lower Receive Level. Threshold of RXLEV received from the serving

BS below which either power control or handover must take place toimprove the cell quality 05.08

MS_TXPWR_CONF MS Transmitted RF Power Confirmation. Parameter sent by the MS toindicate its current transmitted RF power level

MS_TXPWR_MAX_CCH Maximum Allowed Transmitted RF Power for MSs to Access theSystem until commanded otherwise

MS_TXPWR_REQUEST MS Transmitted RF Power Request. Parameter sent by the BSS thatcommands the required MS RF Power Level

MSC Mobile-services Switching Centre (312)MSCM Mobile Station Class MarkMSCU Mobile Station Control UnitMSISDN Mobile Station ISDN Number (719MSRN Mobile Station Roaming Number (720)MT Mobile Terminated (516)MT Mobile Termination (508)MTP Message Transfer PartMUMS Multi User Mobile StationN/W NetworkNB Normal Burst (1041)NBIN A parameter in the hopping sequence 05.02NCELL Neighbouring (or current serving) Cell 05.08NDC National Destination CodeNE Network Element








Contents

Unit 1: Background and Fundamentals

Overview of AGS1200 — The Pan-European GSM Cellular System ................. 1-2AGW1200 Versus CC1200 ................................................................................. 1-4What is GSM? ..................................................................................................... 1-6AGS1200 and the GSM Specification ................................................................. 1-8

BackgroundEvolution of Wireless Access Technology ........................................................ 1-12Wireless Services Technology Perspective........................................................ 1-14Market Trends in Wireless Communication ...................................................... 1-16Cellular Systems in Europe Today .................................................................... 1-18Objectives Of The Pan-European GSM Based System ..................................... 1-20Adoption of GSM Standard ............................................................................... 1-22Key Events ........................................................................................................ 1-24Expected Growth in European — Cellular 1991-1994 ...................................... 1-26Second Generation Cellular Standards .............................................................. 1-28The Radio Spectrum .......................................................................................... 1-30

Cellular SystemPOTS / Mobile Telephone Connections ............................................................ 1-34Layout of a Cellular System .............................................................................. 1-36Multiple Access Methods .................................................................................. 1-38FDMA/TDMA Structure Used in GSM ............................................................ 1-40Spectral Allocation ............................................................................................ 1-42TDMA Operation .............................................................................................. 1-44TDMA Frame Organization for Traffic Channels ............................................. 1-46Multiplexing Voice and Signaling Using 13k bps Speech Coding .................... 1-48Multiplexing 2 Voice Calls Using 6.5k bps Speech Coding.............................. 1-50ISDN-Like Channel Structure Requires 6.5k bps Speech Coding ..................... 1-52

Cellular ConceptsSimple Non-cellular (Non-practical) Wireless System ...................................... 1-56Basic Cellular Principles ................................................................................... 1-58Channel Reuse................................................................................................... 1-60Channel Reuse Example — Using GSM Frequencies ....................................... 1-62Cell Coverage Area ........................................................................................... 1-64Other Cell Clusters ............................................................................................ 1-66Cellular Growth Through Cell Splitting ............................................................ 1-68Continued Growth ............................................................................................. 1-70Sectorized Antennas .......................................................................................... 1-72

Mobile Stations and FeaturesTypes of Mobile Stations .................................................................................. 1-76

Version 1.0


Overview of the GSM Cellular System Contents-1

Unit 2: System Architecture Overview

GSM Land-Mobile Network Reference Model ................................................... 2-2GSM Network Management Architecture ........................................................... 2-4The SS7 Architecture .......................................................................................... 2-6Base Station System (BSS) Architecture ............................................................. 2-8BSS - Continued ............................................................................................... 2-10Mobile-Station/Base-Station Interface .............................................................. 2-12Mobile Services Switching Center (MSC) ........................................................ 2-14BSS/MSC Interface (A) .................................................................................... 2-16MS-BTS-BSC-MSC Signaling Protocol Model ................................................ 2-18Home Location Register (HLR) ........................................................................ 2-20Visitor Location Register (VLR) ....................................................................... 2-22Equipment Identity Register (EIR) .................................................................... 2-24Authentication Center (AUC)............................................................................ 2-26Mobile Application Part (MAP) ........................................................................ 2-28Major Procedures Supported — By Map .......................................................... 2-30Public Land Mobile Networks (PLMNs) .......................................................... 2-32GSM System Area (GSA) ................................................................................. 2-34Service Quality Requirements ........................................................................... 2-36

Unit 3: Mobility Management

Unit Overview ..................................................................................................... 3-2GSM Reference Model ........................................................................................ 3-4

Location AreasPaging a Mobile Station ...................................................................................... 3-8Where is the Mobile Station? ............................................................................ 3-10Paging Performance .......................................................................................... 3-12Location Areas and Cell Areas .......................................................................... 3-14Location and Cell Area Identification................................................................ 3-16Country Codes and Mobile Country Codes — Partial List ............................... 3-18MSC Areas and Location Areas ........................................................................ 3-20Summary of Area Relationships ........................................................................ 3-22Where the HLR Fits in the Picture .................................................................... 3-24

Mobile StationFixed vs. Mobile Station Directory Number Translation................................... 3-28Mobile Station ................................................................................................... 3-30Mobile Station Identification ............................................................................. 3-32Subscriber Identity Module (SIM) .................................................................... 3-34Home Location Register (HLR) ........................................................................ 3-36

Version 1.0


Contents-2 Overview of the GSM Cellular System

Visitor Location Register (VLR) ....................................................................... 3-38Location Update Example — First Time........................................................... 3-40Location Update Example — First Time -- Continued ...................................... 3-42Location Update Example — Movement within VLR Area .............................. 3-44Location Update Example — Movement within VLR Area -- cont. ................. 3-46Location Update Example — Movement between VLRs .................................. 3-48Location Update Example — Movement between VLRs -- cont. ..................... 3-50

Routing CallsMobile Station Roaming Number (MSRN) ....................................................... 3-54MSC Directory Number Allocation .................................................................. 3-56Land to Mobile Call Routing — Mobile Located in Non-Home MSC Area ..... 3-58Land to Mobile Call Routing — Mobile in Home MSC Area ........................... 3-60Land to Mobile Call Routing — Via Gateway MSC ......................................... 3-62Land to Mobile Call Routing — Intelligent PSTN ............................................ 3-64

Mobile Station3 Types of Mobile Station Registration ............................................................. 3-68Geographic Based Registration ......................................................................... 3-70Time Based Registration ................................................................................... 3-72ON/OFF Based Registration ............................................................................. 3-74

Confidentiality andConfidentiality & Security Mechanisms............................................................ 3-78Why Authenticate? ............................................................................................ 3-80Subscriber Identity Authentication and CipherKey Setting ............................... 3-82Authentication Process — Network View ......................................................... 3-84Encrypted Traffic Channel Information ............................................................. 3-86Data Encryption Process ................................................................................... 3-88Why Validate Mobile Equipment? .................................................................... 3-90Equipment Validation Process .......................................................................... 3-92

Detailed LocationPhases of a Mobile Station — Location Registration Update ............................ 3-96Mobile Location Update — Request for Service ............................................... 3-98Mobile Location Update — Authentication .................................................... 3-100Mobile Location Update — Update Location.................................................. 3-102Mobile Location Update — Ciphering ............................................................ 3-104Mobile Location Update — TMSI Reallocation.............................................. 3-106

Unit 4: Call Management

Unit Overview ..................................................................................................... 4-2GSM Reference Model ........................................................................................ 4-4Required Facilities for a Mobile-Land Call ......................................................... 4-6

Mobile to Land

Version 1.0


Overview of the GSM Cellular System Contents-3

Phases of a Mobile to Land Call........................................................................ 4-10Mobile to Land Call — Request for Service ..................................................... 4-12Mobile to Land Call — Authentication ............................................................. 4-14Mobile to Land Call — Ciphering..................................................................... 4-16Mobile to Land Call — Equipment Validation ................................................. 4-18Mobile to Land Call — Call Setup -- with Mobile ............................................ 4-20Mobile to Land Call — Call Setup -- with Land Network ................................ 4-22Mobile to Land Call — Release -- Mobile Initiated .......................................... 4-24

Land to MobilePhases of a Land to Mobile Call........................................................................ 4-28Land to Mobile Call — Routing Analysis ......................................................... 4-30Land to Mobile Call — Paging ......................................................................... 4-32Land to Mobile Call — Authentication ............................................................. 4-34Land to Mobile Call — Ciphering..................................................................... 4-36Land to Mobile Call — Equipment Validation ................................................. 4-38Land to Mobile Call — Call Setup -- with Mobile ............................................ 4-40Land to Mobile Call — Call Setup -- with Land Network ................................ 4-42Land to Mobile Call — Release -- Network Initiated ........................................ 4-44

Mobile to MobilePhases of a Mobile to Mobile Call .................................................................... 4-48

Handover OverviewWhy Handover? ................................................................................................ 4-52Handover Opportunity Window ........................................................................ 4-54Handover Process .............................................................................................. 4-56Mobile Station Measurement Process for Handover -- Example ....................... 4-58Factors that can Influence the Decision to Handover ......................................... 4-60Handover Types — 4 Levels ............................................................................. 4-62Example of Different Handover Types .............................................................. 4-64Intra-MSC Inter-BSS Handover Steps............................................................... 4-66Intra-MSC Inter-BSS Handover Steps — Continued ........................................ 4-68Handover Open Interval Gap -- Example .......................................................... 4-70Inter-MSC Handover Types .............................................................................. 4-72Basic Inter-MSC Handover Steps...................................................................... 4-74Basic Inter-MSC Handover Steps — Continued ............................................... 4-76Subsequent Inter-MSC Handover Steps — Handback ...................................... 4-78Subsequent Inter-MSC Handover Steps — Handback -- Continued ................. 4-80Subsequent Inter-MSC Handover Exercise — 3rd MSC ................................... 4-82Subsequent Inter-MSC Handover Exercise — 3rd MSC -- Continued .............. 4-84Inter-MSC Handover Voice Facilities ............................................................... 4-86MSC Directory Number Spectrum .................................................................... 4-88Inter-MSC Signaling ......................................................................................... 4-90Basic Inter-MSC Handover — Initial Condition ............................................... 4-92

Version 1.0


Contents-4 Overview of the GSM Cellular System

Basic Inter-MSC Handover — Handover Number Allocation .......................... 4-94Basic Inter-MSC Handover — Inter-MSC Trunk Setup .................................... 4-96Basic Inter-MSC Handover — Facilities Before Handover ............................... 4-98Basic Inter-MSC Handover — Events After Handover Command.................. 4-100

Handover ScenariosIntra-BSS Handover ........................................................................................ 4-104Intra-MSC Handover — Steps 1 & 2 .............................................................. 4-106Intra-MSC Handover — Steps 3 & 4 .............................................................. 4-108Inter-MSC Handover — Basic -- Steps 1 & 2 ................................................. 4-110Inter-MSC Handover — Basic -- Steps 3 & 4 ................................................. 4-112Inter-MSC Handover — Basic -- After Call Ends ........................................... 4-114Inter-MSC Handover — Handback -- Steps 1 & 2 .......................................... 4-116Inter-MSC Handover — Handback -- Steps 3 & 4 .......................................... 4-118Inter-MSC Handover — 3rd MSC -- Steps 1 & 2 ........................................... 4-120Inter-MSC Handover — 3rd MSC -- Step 2 continued ................................... 4-122Inter-MSC Handover — 3rd MSC -- Step 3 .................................................... 4-126Inter-MSC Handover — 3rd MSC -- Step 4 .................................................... 4-128

Unit 5: 5ESS MSC

Unit Overview ..................................................................................................... 5-2GSM Reference Model ........................................................................................ 5-4GSM Reference Model — AT&T Product Offering ........................................... 5-6

INTERNATIONAL 5ESSSystem Architecture Overview .......................................................................... 5-10Basic 5ESS Architecture ................................................................................... 5-12Basic 5ESS Wireless Switch Architecture......................................................... 5-1432 Channel Digital Facilities used between MSC and BSSs ............................. 5-16Maximum Digital Facilities per WSM .............................................................. 5-18WSM Trunk Engineering .................................................................................. 5-205ESS WSM Architecture................................................................................... 5-22Wireless Global SM (WGSM) — Logical Signaling Path View ....................... 5-24Example: Facilities between 5ESS and 1 BSS .................................................. 5-26Wireless Global SM (WGSM) — Actual Signaling Path View ........................ 5-28BSS-5ESS Signaling Architecture .................................................................... 5-30MS-BTS-BSC-MSC SIGNALING PROTOCOL MODEL............................... 5-32PSTN & PLMN-5ESS Signaling Architecture .................................................. 5-34MAP SIGNAL PROTOCOL STACK ARCHITECTURE ................................ 5-36PACKET SWITCH UNIT SIGNAL LINK ARCHITECTURE ........................ 5-38GSM Terminology ............................................................................................ 5-40Inter-SM Message Communication ................................................................... 5-42Summary of 5ESS Message — Switching Architecture .................................... 5-44

Version 1.0


The Pan-European GSM Cellular System Contents-5

EXTERNAL DATABASE ACCESS )em High Level View ............................ 5-46WIRELESS DATABASE ACCESS )em Example ........................................... 5-48WIRELESS DATABASE ACCESS )em MAP Message Routing .................... 5-50

HLR, VLR, AUC, and EIRAT&T GSM HLR, VLR, AUC, & EIR............................................................. 5-54Implementation of HLR & VLR on 5ESS......................................................... 5-56Routing Service Requests )em to the Correct VLR ........................................... 5-58TMSI Organization ........................................................................................... 5-60Location of Authentication Center .................................................................... 5-62Location of Equipment Identity Register .......................................................... 5-64

ROAMING MOBILE REGISTRATION SCENARIOROAMING MOBILE REGISTRATION .......................................................... 5-68ROAMING MOBILE REGISTRATION - Cont ............................................... 5-70ROAMING MOBILE REGISTRATION — Request for Service and IMSI

Query............................................................................................................. 5-72ROAMING MOBILE REGISTRATION — Auth., Create New & Cancel

Old VLR........................................................................................................ 5-74ROAMING MOBILE REGISTRATION — TMSI Reallocation, LU

Complete ....................................................................................................... 5-76MOBILE TO LAND CALL SCENARIO

VLR SM & Trunk SM Relationship ................................................................. 5-80SMs Used for a Mobile To Land Call ............................................................... 5-82Phases of a Mobile to Land Call........................................................................ 5-84Mobile to Land Call — Request for Service ..................................................... 5-86Mobile to Land Call — Authentication and Call Setup ..................................... 5-88Mobile to Land Call — Ciphering and Call Setup ............................................ 5-90Mobile to Land Call — Equipment Validation and Call Setup ......................... 5-92Mobile to Land Call — Call Setup .................................................................... 5-94Mobile to Land Call — Mobile Release ............................................................ 5-96

LAND TO ROAMING MOBILE CALLCALL DELIVERY TO A MOBILE STATION — Via Gateway with

External HLR .............................................................................................. 5-102LAND TO ROAMING MOBILE CALL — Routing Information Query ....... 5-104LAND TO ROAMING MOBILE CALL — Routing to VLR MSC and

Paging ......................................................................................................... 5-106LAND TO ROAMING MOBILE CALL — Authentication, BSS Trunk

Hunt, Ciphering ........................................................................................... 5-108LAND TO ROAMING MOBILE CALL — Radio Channel Assignment,

Call Connection ........................................................................................... 5-110INTRA-MSC HANDOVER

Handover Steps ............................................................................................... 5-1144 Steps to a Handover — Switching Voice Paths ............................................ 5-116

Version 1.0


Contents-6 The Pan-European GSM Cellular System

4 Steps to a Handover - continue — Switching Voice Paths ........................... 5-118Intra-MSC Handover — Part 1 ........................................................................ 5-120Intra-MSC Handover — Part 2 ........................................................................ 5-122Intra-MSC Handover — Part 3 ........................................................................ 5-124Intra-MSC Handover — Part 4 ........................................................................ 5-126

INTER-MSC HANDOVER4 Steps to a INTER-MSC Handover — Switching Voice Paths ...................... 5-1304 Steps to a INTER-MSC Handover - continue — Switching Voice Paths ..... 5-132INTER-MSC HANDOVER — Handover Required , New BSS Trunk

Assignment.................................................................................................. 5-134INTER-MSC HANDOVER — ISUP Trunk Setup, Radio Channel

Assignment.................................................................................................. 5-136INTER-MSC HANDOVER — Handover Command, Mobile Retune ............ 5-138INTER-MSC HANDOVER — Handover End, Old BSS Trunk Release ........ 5-1405ESS Terminology Clarification ..................................................................... 5-142

Unit 7: Overview of Japan Cellular

Unit Overview ..................................................................................................... 7-2Overview of Japan Cellular

Japan’s Cellular Networks................................................................................... 7-6800 MHz Band Analog Cellular Telephone Company Overview........................ 7-8800 MHz Band Analog Cellular Telephone Company Map .............................. 7-10Terminal Unit Charges ...................................................................................... 7-12800 MHz Band Digital Cellular Telephone Companies .................................... 7-141.5 GHz Band Digital PCN Cellular Telephone Companies ............................. 7-161.9 GHz Band Digital PHP’s Cellular Telephone Companies ........................... 7-18Japan’s Telecommunication Standards .............................................................. 7-20Japan TTC OVERVIEW ................................................................................... 7-24Japan TTC Overview Diagram .......................................................................... 7-26Japan RCR Overview ........................................................................................ 7-28Japan RCR Overview Diagram ......................................................................... 7-30MSC<->BSS<->MS Protocol Model ................................................................ 7-32Japan DMNI Overview ..................................................................................... 7-34Japan DMNI Overview Diagram ....................................................................... 7-36JAPAN to GSM Model Comparison Diagram .................................................. 7-42JAPAN Network Parameters ............................................................................. 7-44

IDO OverviewIDO Overview ................................................................................................... 7-48IDO’s Network Architecture ............................................................................. 7-50IDO’s 5ESS Architecture .................................................................................. 7-52IDO’s 5ESS Supplementary Services ................................................................ 7-54

Version 1.0


The Japan Digital Cellular System Contents-7

IDO Documentation Status ............................................................................... 7-56Japan Cellular Network Call Scenarios

Location Registration - Home Subscriber ......................................................... 7-60Location Registration - Visiting Subscriber ...................................................... 7-62Call Termination - Home MS ............................................................................ 7-64Call Termination - Visitor ................................................................................. 7-66

Appendix 1: Index to GSM Specification Document

Index to GSM Specification Document ............................................... Appendix 1-2

Appendix 2: Obtaining Copies of the GSM Recommedations

Requesting a Copy of GSM via LINUS ............................................... Appendix 2-2

Appendix 3: Glossary of GSM Terms -- GSM 01.04

Glossary of GSM Terms -- GSM 01.04 ............................................... Appendix 3-2

Version 1.0


Contents-8 The Pan-European GSM Cellular System

Version 1.0


The Pan-European GSM Cellular System Contents-10

Date post:	27-Apr-2015
Category:	Documents
Upload:	jhon-vargas-reyes
View:	832 times
Download:	2 times