PRESENTED BY - AMAN RAJ - KIIT UNIVERSITY

SCHOOL OF COMPUTER ENGINEERINGDATE – 09/06/2015

MENTOR – ANURAKAR MISHRA NSS ENGINEER

( ERICSON PATNA)

GSM TECHNOLOGY

GLOBAL SYSTEM FORMOBILE COMMUNICATION

Points covered• History of GSM technology• Definition of GSM• Basic definition of terms used in GSM • GSM architecture• Call flow• Present scenario of GSM

HISTORY OF GSMThe idea of the first cellular network was brainstormed in 1947It was intended to be used for military purpose as a way of supplying troops with more advanced forms Of communicationFrom 1947 -1979 several different forms of brodcasting technology emerged• USA began to develop AMPS(advance mobile phone

service) network• European countries were developing their own forms of

communication

DEVELOPMENT OF GSM

Europeans quickly realized the disadvantages of each European country operating on their mobile network, it prevents cell phone use from country to country within EuropeFor the purpose of rectifying the situation the conference of European posts and telegraphs(C E P T)Assembled a research group with intentions of researching the mobile phone system in EuropeGroup called group special mobile (GSM)For the next 10 years GSM group outlined standardsResearched technology and designed a way to implement pan European mobile phone network

IMPLEMENTATION OF GSMIn 1989 work done by GSM was transferred to European telecommunication standard institute(ETSI)GSM new name was given global system mobile telecommunicationIn 1991 commercial service of GSM network had begunIn 1993 there were 36 GSM networks in over 22 countriesTill now usa was using old analog AMPS network and tdmaIn October 2001 ,cingular the first to anounce to switch to 3g GSM network involved more then 22 million customers switching from tdma to GSM networkIn 2005 cingular stopped new phone activation on TDMA ,began Selling only GSM service

GSM FREQUENCY STANDARD WORLDWIDE

GSM-900 AND GSM-1800Standard used mostly worldwide, frequency where European phones operate on as well as Asia and Australia

GSM-850 AND GSM-1900Used primarily by usa, also standard for Canada, countries in Latin and south AmericaCingular network operate on GSM-850T-Mobile operate on GSM-1900T mobile has roaming agreements with cingularMeaning in case no service at GSM-1900,the phone will switch to GSM-850 and operate on cingular network

GSM-400Least popular of the bunch and rarely used

WHICH PHONE OPERATES ON WHICH NETWORKThere are four different frequencies that GSM phones operate on,it is important to purchase your phone from cell phone company, must match with the frequency of the service provider we useissues arises when we buy a cell phone internationally• DUAL BAND PHONEOperating on two frequency any two• TRI BAND PHONEOperating on three frequency• QUAD BAND PHONEOperating on four frequency

DEFINITION OF GSMGlobal system for mobile communication is an openDigital cellular technology used for transmitting mobile voice and data services• GSM supports voice calls & data transfer speed up to

9.6kbps• Allows travellers to access the same mobile service at home

or abroad• It enables individual to reach via same mobile number over

219 countries• GSM network covers almost 90% of world population

S I msubscriber identity module

WHAT IS SIMA sim card known as a subscriber identity module, is a subscriber identity module application on a smartcard that stores data for GSM –CDMA cellular telephone subscribersSuch data includes user identity, network authorization data, personal security keys, contact lists and stored text messages

Security features include authentication and encryption to protect data and prevent eavesdropping

A smart card with subscriber identity module application is generally known as simcard

When a simcard is viewed as a smartcard, it opens up security possibilities that resonate far beyond mobile world

FUNCTIONS OF SIM CARD

IDENTIFICATIONIdentification of a subscribe::the IMSI programed on the sim card is the identity of the subscriber Each IMSI is mapped to a mobile number and provisioned on the HLR to allow a subscriber to be identified

AUTHETICATIONHere we use authentication algorithm on the sim cardA unique response is provided by each subscriber based onIMSI,KI(STORED ON SIM)::RAND (PROVIDED BY NETWORK)By matching this response with values computed on the network a legal subscriber is logged on and now he can use the services of the mobile service provider

STORAGETo store phone number and sms

APPLICATIONThe sim tool kit or GSM 11.14 standard allows creating application on the sim to provide basic info on demand like chatting

WHY SIM CARD IS SECURESIMCARD IN REALITY IS A MASS MARKET SMARTCARD WITH SUBSCRIBER IDENTITY MODULESMART CARD IS VERY SECURE• SECURE LOADING OF APPLICATION• SECURE DATA STORAGE FOR APPLICATION DATA• SECURE CRYPTO OPERATION SUPPORTPRESENCE OF CRYPTOGRAPHIC ALGORITHM AND SECRET KEY IN SIM CARD MAKES THE SIM CARD SECUREPINPERSONAL IDENTIFICATION NUMBER2 PINs EXISTS(PIN1 & PIN2)LIMITED ATTEMPT OF PIN ACESSPUKPIN UNBLOCKING CODERESETTING PUK RESETS PIN AND ATTEMOT COUNTERTOO MANY ATTEMPTS ON PUK BLOCKS USE PERMANENTLY

TWO WAYS OF STORING DATA IN SIMAs GSM filesThe data used for telco and GSM operation are all stored over filesTelco operator can change the data through RFM in secure channelAs application dataM check STORES ALL ITS SECURED ENCRYPTED INFORMATION WITHIN APPLICATION DATAData on sim is protected by administrative keys which are in hexadecimal and it has been proved that compromising the security of sim requires enormous supercomputing abilityAnd lots of time to crack a single cardWe can conclude that sim card is so secure that it is ideal for banking operation to be ported on.

wireless system

MEANING OF WIRELESS

Wireless is defined as having no wires

In networking terminilogy,wireless is term used to describe any computer network where there is no physical wired connection between sender and receiver

Network is connected by radio waves or microwaves to maintain communication

Wireless networking utilizes specific equipment such as nic and routers in place of wires

1G TECHNOLOGY• Refers to first generation of wireless telephone

technology• Introduced in 1980 and completed in 1990• Speed 2.4kbps• Allows voice call in one country• Uses analog signal• Amps was first launched in usa in 1G mobile system Drawbacks of 1G• Poor voice quality• Poor battery life• Large phone size• No security• Limited capacity

2G TECHNOLOGY• 2G technology refers to 2nd generation based on GSM• Launched in Finland in 1991• Uses digital signal• Data speed was 64kbps• Enables services such as text messages picture messages

& MMS(multi media message)• Better quality and capacityDrawbacks of 2G• Requires strong digital signal to help mobile phones work,

no network coverage, weak digital signal• Unable to handle complex data such as videos

3G TECHNOLOGY• Introduced in year 2000• Data transmission speed increased from 144kbps-2mbps• Generally called as smart phones with increased

bandwidth and data transmission rate to accommodate web based application

• Faster coomunication,send receive large email,High speed web, more security, video conferencing,3d games,mobile tvDrawbacks of 3G• Expensive fees of 3G licenses services• Expensive 3G phones• Large cell phones• High bandwidth requirement

4G TECHNOLOGY

• Started from late 2000• Capable of providing up to 1gbps speed• One of the basic term used to describe 4G is magic• Mobile multimedia, global mobility support,

integrated wireless solution, customized personnel service

Drawbacks of 4G• Battery use is more• Hard to implement• Complicated hardware

5G TECHNOLOGY

• Started in 2010• Complete wireless communication• High speed & high capacity• Support interactive multimedia• 5G is more effective and more attractive

EVOLUTION OF TECHNOLOGY

GSM Concepts - Cellular Structure

CellularNetworking technology that breaks geographic area into cells shaped like honey comb

CellIs the radio coverage area of one base transceiver station

1

23

45

6

76

72

1

5

• Frequency band • uplink 890 - 915 m h z• Downlink 935 – 960 m h z• Duplex frequency spacing 45mhz• Carrier separation 200 k h z• Frequency channels 124• Time slots /frame(full rate) 8• Voice coder bit rate 13kbps• Modulation g m s k• Air transmission rate 270.833333 kbps• Access method FDMA/TDMA• Speech coder RPE-LTP-LPC

GSM SYSTEM SPECIFICATION

GSM TECHNOLOGY LAYERS

7-layer osi model• ISO

– International standards organizationOSI– Open systems interconnect

OSI model background

• Introduced in 1978 and revised in 1984• Formulates the communication process into structured layers• There are seven layers in the model, hence the name the 7-layer model• The model acts as a frame of reference in the design of communications

and networking products

THE LAYERED APPROACH TO COMMUNICATION

7. Application

6. Presentation

5. Session

4. Transport

3. Network

2. Data Link

1. Physical

7.Application layer• Purpose

– User application to network service interface• Examples

– File request from server– E-mail services– Etc.

• General network access• Flow control• Error recovery

6. Presentation layer• Purpose

– Formats data for exchange between points of communication• Ex: between nodes in a network

• Example:– Redirector software

• Formats for transmission to the server• Protocol conversion• Data translation• Encryption• Character set conversion• Expansion of graphics command

5. Session layer• Purpose

– Oversee a communication session• Establish• Maintain• Terminate

• Performs name recognition and related security• Synchronization between sender and receiver• Assignment of time for transmission

– Start time– End time etc.

4. Transport layer• Purpose

– Repackage proper and efficient delivery of packages• Error free• In sequence• Without duplication

• Example• For sending data

– Repackage the message to fit into packets• Split long messages• Assemble small messages

• On receiving data– Perform the reverse– Send an acknowledgment to the sender

• Solve packet problems– During transmission and reception

3. Network layer• Purpose

– Addressing and routing the packets• Example application at the router

– If the packet size is large, splits into small packets• Purpose

– Addressing and routing the packets• Example application at the router

– If the packet size is large, splits into small packets

2. Data link layer• Purpose

– Manages the flow of data over the physical media• Responsible for error-free transmission over the physical media• Assures error-free data submission to the network layer• Point of origin

– Packages data for transmission over physical line• Receiving end

– Packages data for submission to the network layer• Deals with network transmission protocols

– Ieee 802. Protocols

1. Physical layer• Purpose

– Deals with the transmission of 0s and 1s over the physical media• Translation of bits into signals

• Example– Pulse duration determination– Transmission synchronization– Etc.

• Encode bits into signals– Carry data from the h higher layers

• Define the interface to the card– Electrical– Mechanical– Functional– Example: pin count on the connector

SIGNALING SYSTEM – (SS7)• Common channel signalling system no. 7 (i.E., SS 7or C7) is a global standard for• Telecommunications defined by the international telecommunication union (ITU)• Telecommunication standardization sector (ITU-T). The standard defines the

procedures and• Protocol by which network elements in the public switched telephone network

(PSTN) exchange• Information over a digital signalling network to effect wireless (cellular) and wire

line call setup,• Routing and control. The itu definition of SS7 allows for national variants such as

the American• National standards institute (ANSI) and bell communications research (telcordia

technologies)• Standards used in north America and the European telecommunications standards

institute• (ETSI) standard used in Europe.

CONCEPT OF E1….1 e1 = 8000 frames / sec1 frame = 32 timeslots1 timeslot = 8 bits

E1 (2048 kbps) = 8000 frames/sec X 32 timeslots/frame X 8 bits/timeslot

= 8000 frames/sec X 256 bits/frame

= 2048000 bits/sec

E1 STRUCTURE

1ST FRAME 2ND FRAME 3RD FRAME 8000TH FRAME

32 TIMESLOTS / FRAME0TH 1ST 2ND 3RD 31ST

1ST 2ND 8TH7TH6TH5TH4TH3RD

8 BITS / TIMESLOT

8000 FRAMES / SEC

CHANNEL CONCEPTS….• Physical channel:• One timeslot of a tdma-frame on one carrier• Is referred to as a physical channel.• There are 8 physical channels per carrier in• GSM,channel 0-7(timeslot 0-7)

• Logical channel:• A great variety of information must be • Transmitted between bts and the MS, for e.g.• User data and control signaling. Depending• On the kind of information transmitted we • Refer to different logical channels.These logical• Channels are mapped on physical channel.

LOGICAL CHANNELS ON AIR INTERFACELOGICALCHANNELS

COMMONCHANNELS

DEDICATED CHANNELS

BROADCAST CHANNELS

COMMONCONTROLCHANNELS

DEDICATED CONTROL CHANNELS

TRAFFIC CHANNELS

FCCH BCCHSCH SDCCH SACCH FACCH

PCH AGCHRACH TCH/F TCH/EFRTCH/H

Broadcast channels BCH • Broadcast channel-BCH

– Allowed one arfcn & is on all the time in every cell. Present in TS s 0 and other 7 TS used by TCH.

• Frequency correction channel-FCCH • To make sure this is the BCCH carrier.

– Allow the m s to synchronize to the frequency.– Carries a 142 bit zero sequence and repeats once in every 10 frames on the BCH.

• Synchronization channel-SCH– This is used by the m s to synchronize to the TDMA frame structure within the particular cell.– Listening to the s c h the m s receives the tdma frame number and also the BSIC ( in the coded part- 39 bits).– Repeats once in every 10 frames.

Common control channels CCCH • CCCH

– Shares ts-0 with bch on a multiframe.

• Random access channel-RACH:– Used by mobile station for requesting for a channel. When the mobile realizes it is paged it answers by

requesting a signaling channel (SDCCH) on r ach. RACH is also used by the MS if it wants to originate a call.– Initially MS doesn’t know the path delay (timing advance), hence uses a short burst (with a large guard period

= 68.25 bits).– M s sends normal burst only after getting the timing advance info on the SACCH– It is transmitted in uplink point to point.

• Access grant channel-AGCH– On request for a signaling channel by MS the network assigns a signaling channel( SDCCH) through AGCH.

AGCH is transmitted on the downlink point to point.

• Paging channel-PCH– The information on this channel is a paging message including the m s’s identity(IMSI/TMSI).This is

transmitted on downlink, point-to-multipoint.

Dedicated control channels-dcch

• Stand alone dedicated control channel(SDCCH)• A g c h assigns SDCCH as signaling channel on request by MS .The MS is informed about which

frequency(ARFCN) & timeslot to use for traffic. • Used for location update, subscriber authentication, ciphering information, equipment validation and

assignment of TCH.• This is used both sides, up and downlink point-point.• Slow associated control channel-SACCH

– Transmission of radio link signal measurement, power control etc.– Average signal strengths(RXLEV) and quality of service (RXQUAI) of the serving base station and of the

neighboring cells is sent on SACCH (on uplink).– Mobile receives information like what TX power it has to transmit and the timing advance. It is associated

with TCH or SDCCH• Fast associated control channel-FACCH

– Used for hand over commands and during call setup and release. FACCH data is sent over TCH with stealing flag set

– Traffic channels-tch

• TCH carries the voice data.• Two blocks of 57 bits contain voice data in the normal burst.• One TCH is allocated for every active call.• Full rate traffic channel occupies one physical channel(one TS on a carrier) and carries voice data at 13kbps• Two half rate (6.5kbps) TCH can share one physical channel.

C D M A GSM• global system for mobile

communication• sim storage type• dominant standard worldwide

except us• G p r s/e/3g/4g/l t e• every cell has corresponding

network tower which serves mobile phones in that area

• most accessible• multiple(850/900/1800/1900)• sim specific. User has option to

select handset of his choice

C d m a vs GSM

• code division multiple access• internal memory storag e type• global market 25%• dominant standard in us• data transfer eddo/3g/4g/l t e• international roaming less

accessible• frequency band single(850 m

h z )• network service ,handset

specific

GSM ARCHITECTURE

TERMS USED IN GSMMobile station(MS)The mobile station (MS) consists of the physical equipment used by PLMN

Subscriber to connect to the networkIt comprises the mobile equipment(ME)and sim

The me forms part of mobile termination (MT) depending upon the application and the services may also include various kind of terminal equipment (TE) & terminal adapter(TA)

COMPONENTS OF MOBILE STATION

Subscriber identity -MSISDN• The MSISDN is a GSM directory number which uniquely

identifies a mobile subscription in the public switched telephone network (PSTN).

• Calls will be routed from the PSTN and other networks based on the mobile subscribers’ MSISDN number.

• MSISDN= CC + NDC + SN– CC= country code (91)– NDC= national destination code(98370)– SN= subscriber number (12345)

INTERNATIONAL MOBILE SUBSCRIBER IDENTITY [IMSI]

• Subscriber always identified within the GSM network by the IMSI

• This is used for all signaling in the p l m n stored in s I m and H L R/V L R

• The I m s i consists of three different parts– M NC = mobile network code(2 digits)– M CC = mobile country code(3 digits)– MSIN = mobile station identification number(up to 10 digits)

TEMPORARY MOBILE SUBSCRIBER IDENTITY [TMSI]

• The TMSI is used for the subscriber’s confidentiality.

• It should be combined with the l a i to uniquely identify AMS.

• Since the t m s i has only local significance (that is, within the M S C/V L R area), the structure may be chosen by each administration.

• The T M S I should not consist of more than four octets.

Mobile Station Roaming Number[MSRN]

• HLR knows in what service area the subscriber is located.

• In order to provide a temporary number to be used for routing, the HLR requests the current M S C/V L R to allocate a mobile station roaming number(MSRN) to the called subscriber and to return it.

• At reception of the M S R N, H L R sends it to the MSC, which now can route the call to the VLR where the called subscriber is currently registered.

INTERNATIONAL MOBILE EQUIPMENT IDENTITY [IMEI]

• The IMEI is used for equipment identification. An IMEI Uniquely identifies a mobile station as a piece or assembly of equipment.

• IMEI = TAC + FAC + SNR + SP– T A C= type approval code (6 digits),determined by GSM body– F A C= final assembly code (2 digits), identifies the manufacturer– S N R= serial number (6 digits), uniquely identifying all

equipment within each TAC and FAC– S P = spare for future use (1 digit)

BASE STATION SUBSYSTEM (BSS)TWO PARTS OF BSS• BTS• BSC

Base Station Subsystem (BSS)Base Transceiver Station (BTS)Base Station Controller (BSC)

• Network SubsystemMobile Switching Center (MSC)Home Location Register (HLR)Visitor Location Register (VLR)Authentication Center (AUC)Equipment Identity Register (EIR)

• Authentication Center (AUC) - mainly used for security- data storage location and functional part of the network- Ki is the primary element

• Equipment Identity Register (EIR)- Database that is used to track handsets using the IMEI

(International Mobile Equipment Identity)- Made up of three sub-classes: The White List, The Black List

and the Gray List- Optional database

BASE TRANSCEIVER STATION (BTS)

The base transceiver station (BTS) is a term used to denote a base station in GSM terminology. A BTS consists of an antenna and the radio equipment necessary to communicate by radio with a mobile station (MS). Each b t s covers a defined area, known as a cell. A BTS is under control of a BSC, which is in turn under control of a MSC (mobile switching centre).

POWER SUPPLY TO BTS

BASE STATION CONTROLER (BSC)

• He base station controller (BSC) is in control of and supervises a number of base transceiver stations (BTS). The BSC is responsible for the allocation of radio resources to a mobile call and for the handovers that are made between base stations under his control. Other handovers are under control of the MSC.

Mobile switching centre-m s c

The mobile switching centre (MSC)Is a telephone exchange that makes the connection between mobile users within the network from mobile users within the network and from mobile users to other mobile network The MSC also administrate handovers to neighbouring base station, keeps a record of the location of the mobile subcriber,is responsible for subscriber service and billing

HOME LOCATION REGISTER(HLR)The home location register is a database from a mobile network in which information from all mobile subscribers is stored. The HLR contains information about the subscribers identity, his telephone

number, the associated services and general information about the location of the subscriber. The exact location of the subscriber is kept in a visitor location register.Visitor location register (VLR)The visitor location register (VLR) is a database in a mobile communications network associated to a mobile switching centre (MSC). The VLR contains the exact location of all mobile subscribers currently present in the service area of the MSC. This information is necessary to route a call to the right base station. The database entry of the subscriber is deleted when the subscriber leaves the service area.

GATEWAY MOBILE SWITCHING CENTRE(GMSC)

• The gateway mobile switching centre (GMSC) is a special kind of MSC that is used to route calls outside the mobile network. Whenever a call for a mobile subscriber comes from outside the mobile network, or the subscriber wants to make a call to somebody outside the mobile network the call is routed through the GMSC.

• In practice, the GMSC is just a function that can be part of AMSC.

AUTHENTICATION CENTER (AUC)

• Stores subscriber authentication data called k I, a copy of which is also stored in in the SIM card

• Generates security related parameters to authorize a subscriber (SRES-signed response)

• Generates unique data pattern called cipher key (KC) for user data encryption

• Provides triplets - RAND, SRES & KC, to the HLR on request.

CALL FLOW

MOBILE ORIGINATED CALL

54

MS

MS

BTS

BTS

BTS

BSC

BSCMSC

VLR

GMSC

HLR

PSTN

EIR

AuC

Req for dedicated channel for signaling (RACH)

Give SDCCH

Allocates SDCCH using the AGCH

Sends call set-up request including dialled digits on SDCCH

Call set-up forwarded to BSC

Call set-up forwarded to MSC

Authentication request(SDCCH)

Authentication response(SDCCH)

Authentication response(SDCCH)

Assigns TCH Req

Activate TCHTCH assigned

Assn complete

Release SDCCH

SDCCH released

ACM

Ring tone over FACCH

Ring alert

Called Sub answers

Connect message

Ring tone ceases over FACCH Speech path enabled

NEW FEATURE OF GSM

Mobile number portability

• There has been rapid growth in the penetration of telephony services in the last few years. But the growth has not been

• Exponential in the quality of service offered or openness of business.• Consumers are not satisfied with the operators’ services and schemes. • Traditionally, consumers are required to give up their mobile number on changing

service providers. As a result, they are hugely inconvenienced by having to inform everyone about the change in their number.

• Besides there is likelihood of important calls (from people who didn’t have the new number) being missed out, and so on.

• The picture has now changed dramatically with the introduction of mobile number portability (MNP)

TYPES OF MNP• Mobile number portability mobile number portability enables consumers to retain their mobile

numbers when changing service providers, service types and/or locations. The internet engineering task force (I e t f) has defined three types of number portability: service provider portability, location portability and service portability.

• Service provider portability: it enables a customer to retain his existing mobile number when changing from one service provider to another in the same area.

• Location portability: it enables a customer to retain his existing mobile number without impairment of quality, convenience or reliability when shifting from one geographic location to another.

• Service portability: it enables a customer to retain his existing mobile number without impairment of quality, convenience or reliability when switching from one service technology to another service technology—for example, from c d m a to GSM.

Mnp terminology

• Donor operator. Operator from whose network the customer is porting out.• Recipient operator. Operator who will be providing services to the customer after porting. • Number portability database. Collection/repository of all the ported numbers. Provides a unique

routing number in response to a query from any network operator. • Routing number. A unique number stored in the number portability database that is used to route the

call to the recipient operator

DATABASE STRUCTURE

DISTRIBUTED DATABASE CENTRALISED DATABASE

CONCLUSION……Basic features provided by GSM• Call waiting

- Notification of an incoming call while on the handset• Call hold

- Put a caller on hold to take another call• Call barring

- All calls, outgoing calls, or incoming calls• Call forwarding

- Calls can be sent to various numbers defined by the user• Multi party call conferencing

- Link multiple calls together- Advanced features provided by GSM

• Calling line id- Incoming telephone number displayed

• Alternate line service- One for personal calls- One for business calls

• Closed user group- Call by dialing last for numbers

• Advice of charge- Tally of actual costs of phone calls

• Fax & data- Virtual office / professional office

• Roaming- Services and features can follow customer from market to market

ADVANTAGES OF GSM • Crisper, cleaner quieter calls• Security against fraud and eavesdropping• International roaming capability in over 100 countries• Improved battery life• Efficient network design for less expensive system expansion• Efficient use of spectrum• Advanced features such as short messaging and caller id• A wide variety of handsets and accessories• High stability mobile fax and data at up to 9600 baud• Ease of use with over the air activation, and all account

information is held in a smart card which can be moved from handset to handset

T H A N K Y O U