Umts Booklet

8/8/2019 Umts Booklet

http://slidepdf.com/reader/full/umts-booklet 1/25

UMTS booklet

Made by

Jalal Bershan

&

Mohamad Dankar

Supervised by

Dr Khaled Mawas

November 2010







MSC/VLR : Main Switch Controller / Visitor Location Register

GMSC : Gateway Main Switch Controller

HLR: Home Location Register

AC : Authentication Center

GGSN : Gateway GPRS Support Node

SGSN : Serving GPRS Support Node

PSTN : Public Switched Telephone Network



PMD : Public Data Network

RNC: Radio Network Controller

Node B : BTS = Base Transceiver Station

UE : User Equipment

TAF : Traffic Asymmetry Factor

Iu: Interface between the RNC and the Core Network (MSC or SGSN).

- Iucs: Iu circuit switched (voice from/to MSC)

- Iups: Iu packet switched (data from/to SGSN)

Iub: Interface between the RNC and the Node B.

Iur: Interface between two RNCs.

Gs: MSC/VLR SGSN

Gn : SGSN GGSN

E : MSC/VLR GMSC

C : HLR GMSC

D : MSC/VLR HLR

Gr: SGSN HLR

Gc: GGSN HLR

H : HLR AC

Gi: GGSN PDN



UMTS combines three different air interfaces, GSM's Mobile Application Part (MAP) core, and the GSM

family of speech codecs.

UMTS provides several different terrestrial air interfaces, calledUMTS Terrestrial Radio

Access (UTRA).All air interface options are part of ITU's IMT-2000. In the currently most popular variant

for cellular mobile telephones, W-CDMA (IMT Direct Spread) is used. Please note that the terms W-

CDMA, TD-CDMA and TD-SCDMA are misleading. While they suggest covering just a channel accessmethod (namely a variant of CDMA), they are actually the common names for the whole air interface

standards. Non-terrestrial radio access networks are currently under research.

W-CDMA uses the DS-CDMA channel access method with a pair of 5 MHz channels. In contrast, the

competing CDMA2000 system uses one or more arbitrary 1.25 MHz channels for each direction of

communication. W-CDMA systems are widely criticized for their large spectrum usage, which hasdelayed deployment in countries that acted relatively slowly in allocating new frequencies specifically

for 3G services (such as the United States). The specific frequency bands originally defined by the UMTS

standard are 18852025 MHz for the mobile-to-base (uplink) and 2110 2200 MHz for the base-to-

mobile (downlink).

UMTS-TDD's air interfaces that use the TD-CDMA channel access technique are standardized asUTRA-

TDD HCR, which uses increments of 5 MHz of spectrum, each slice divided into 10ms frames containing

fifteen time slots (1500 per second). The time slots (TS) are allocated in fixed percentage for downlink

and uplink. TD-CDMA is used to multiplex streams from or to multiple transceivers. Unlike W-CDMA, it

does not need separate frequency bands for up- and downstream, allowing deployment in tight

frequency bands. TD-CDMA is a part of IMT-2000 as IMT CDMA TDD.



TD-SCDMA uses the TDMA channel access method combined with an adaptive synchronous

CDMA component on 1.6 MHz slices of spectrum, allowing deployment in even tighter frequency bandsthan TD-CDMA. However, the main incentive for development of this Chinese-developed standard was

avoiding or reducing the license fees that have to be paid to non-Chinese patent owners. Unlike the

other air interfaces, TD-SCDMA was not part of UMTS from the beginning but has been added in Release

4 of the specification. Like TD-CDMA, it is known as IMT CDMA TDD within IMT-2000.

UMTS also specifies the UMTS Terrestrial Radio Access Network (UTRAN), which is composed of

multiple base stations, possibly using different terrestrial air interface standards and frequency bands. UMTS and GSM/EDGE can share a Core Network (CN), making UTRAN an alternative radio access

network to GERAN (GSM/EDGE RAN), and allowing (mostly) transparent switching between the RANs

according to available coverage and service needs. Because of that, UMTS' and GSM/EDGE's radio access

networks are sometimes collectively referred to asUTRAN/GERAN. UMTS networks are often combined

with GSM/EDGE, the later of which is also a part of IMT-2000. The UE (User Equipment) interface of the

RAN (Radio Access Network) primarily consists of RRC (Radio Resource Control), RLC (Radio Link Control)

and MAC (Media Access Control) protocols. RRC protocol handles connection establishment,

measurements, radio bearer services, security and handover decisions. RLC protocol primarily divides

into three Modes - Transparent Mode (TM), Unacknowledge Mode (UM), Acknowledge Mode (AM). The

functionality of AM entity resembles TCP operation where as UM operation resembles UDP operation.

In TM mode, data will be sent to lower layers without adding any header to SDU of higher layers. MAC

handles the scheduling of data on air interface depending on higher layer (RRC) configured parameters. Set of properties related to data transmission is called Radio Bearer (RB). This set of properties will

decide the maximum allowed data in a TTI (Transmission Time Interval). RB includes RLC information

and RB mapping. RB mapping decides the mapping between RB<->logical channel<->transport channel.

Signaling message will be send on Signaling Radio Bearers (SRBs) and data packets (either CS or PS) will

be sent on data RBs. RRC and NAS messages will go on SRBs. Security includes two procedures: integrity

and ciphering. Integrity validates the resource of message and also make sure that no one

(third/unknown party) on radio interface has not modified message. Ciphering make sure that no one

listens your data on air interface. Both integrity and ciphering will be applied for SRBs where as onlyciphering will be applied for data RBs.



With Mobile Application Part, UMTS uses the same core network standard as GSM/EDGE. This allows a

simple migration for existing GSM operators. However, the migration path to UMTS is still costly: while

much of the core infrastructure is shared with GSM, the cost of obtaining new spectrum licenses and

overlaying UMTS at existing towers is high. The CN can be connected to various backbone networks like

the Internet, ISDN. UMTS (and GERAN) include the three lowest layers of OSI model. The network layer

(OSI 3) includes theRadio Resource Management protocol (RRM) that manages the bearer channels

between the mobile terminals and the fixed network, including the handovers.

Bearer

Teleservices

Supplementary Services

Bearer - telecommunication services providing the capability of transmission of signals between access

points.

Teleservices - telecommunication services providing the complete capability for communication

between users according to specified protocols

Supplementary Services - modifies or supplements a basic telecommunication service.



Speech call

Emergency call

H.324 video call

Real-time fax

Short Message Service (SMS)

Short Message Service Point-to-Point (SMS-PP)

Short Message Service Cell Broadcast (SMS-CB)

Terminal & USIM

Service Platform

3G Network

Service Platform

Teleservices Teleservices

Access Methods: - WCDMA- GSM900/1800 - etc.

Open / Proprietary Interface

Open Interface

Software in Terminal HLR, SMSC, VMS, IN

Terminal & USIM BS, RNC, MSC

Delay Result

0 to 150 ms Preferred range [<30ms, user does not notice anydelay at all, <100ms, user does not notice delay if echo cancellation is providedand there are nodistortions on the link]

150 to 400 ms Acceptable range (but with increasing degradation)

> 400 ms Unacceptable range



Codecs for real-time voice,

data and video.

Functionality of H.324 can be

included in a PC or a stand-

alone device/terminal.

May also be used in multipoint configurations through a MCU (Multipoint Control Unit).



Voice over IP

Voice and video over IP

Data

Voice messaging

SMS via packet

Point-to-multi-

point, multicast

via SGSN



Web browsing

Interactive games

High-priority transaction services

(E-commerce)

Store and forward fax

E-mail (server access)



First standardised in GSM phase 2+ specifications by ETSI/3GPP (11.11 and 11.14).

Enables the operator to remotely update the SIM, alter and download services.

Increases the subscriber's possibility to, for example, change service profile.

SMS is a key mechanism in SIM Application Toolkit.







UMTS phones (and data cards) are highly portablethey have been designed to roam easily onto other

UMTS networks (if the providers have roaming agreements in place). In addition, almost all UMTS

phones are UMTS/GSM dual-mode devices, so if a UMTS phone travels outside of UMTS coverage duringa call the call may be transparently handed off to available GSM coverage. Roaming charges are usually

significantly higher than regular usage charges. UMTS phones can use a Universal Subscriber Identity

Module, USIM (based on GSM's SIM) and also work (including UMTS services) with GSM SIM cards. This

is a global standard of identification, and enables a network to identify and authenticate the (U)SIM in

the phone. Roaming agreements between networks allow for calls to a customer to be redirected to

them while roaming and determine the services (and prices) available to the user. In addition to user

subscriber information and authentication information, the (U)SIM provides storage space for phone

book contact. Handsets can store their data on their own memory or on the (U)SIM card (which is

usually more limited in its phone book contact information). A (U)SIM can be moved to another UMTS

or GSM phone, and the phone will take on the user details of the (U)SIM, meaning it is the (U)SIM (notthe phone) which determines the phone number of the phone and the billing for calls made from the

phone.

All of the major 2G phone manufacturers (that are still in business) are now manufacturers of 3G

phones. The early 3G handsets and modems were specific to the frequencies required in their country,

which meant they could only roam to other countries on the same 3G frequency (though they can fall

back to the older GSM standard).

Canada and USA have a common share of frequencies, as do most European countries. The

article UMTS frequency bands is an overview of UMTS network frequencies around the world.



Using a cellular router, PCMCIA or USB card, customers are able to access 3G broadband services,

regardless of their choice of computer (such as a tablet PC or a PDA). Some software installs itself from

the modem, so that in some cases absolutely no knowledge of technology is required to get online in

moments. Using a phone that supports 3G and Bluetooth 2.0, multiple Bluetooth-capable laptops can

be connected to the Internet. Some smartphones can also act as a mobile WLAN access point. There are

almost no 3G phones or modems available supporting all 3G frequencies

(UMTS850/900/1700/1900/2100 MHz). However, many phones are offering more than one band which

still enables extensive roaming. For example, a tri-band chipset operating on 850/1900/2100 MHz, such

as that found in Apple's iPhone, allows usage in the majority of countries where UMTS-FDD is deployed.



Basic reason for a handover: the same as in the GSM

2 main types of handover in WCDMA

² soft: the "old" radio link connection is maintained when the "new" radio link connection

is gained.

² Hard: the "old" radio link connection is released before the UE accesses the network

through the "new".

Roughly, the criteria for the handover is based on the same items as in GSM (next slide).



UE stops transmission on one frequency before it moves to another

frequency and starts transmitting again

During Hard Handover the used radio frequency (RF) of the UE changes

4

B SB S

Frequency f1

Frequency f1

R N C R N CIur

Iub Iub

4

B TB S

WCDMA GSM900/1800



UE is connected simultaneously to more than one base station (up to 3

sectors) using the same frequency

The UE receives the downlink transmissions of two or more base stations.

For this purpose it has to employ one of its RAKE receiver fingers for each

received signal.

in the uplink direction , the code channel of the mobile station is received

from both base stations, but the received data is then routed to the RNC for

combining

The RNC selects the better frame between the two possible candidates

based on frame reliability indicator

B SB S

Frequency f1

Frequency f1



UE is connected simultaneously to two sectors of one base station using the

same frequency

The UE receives the downlink transmissions the two sectors. For thispurpose it has to employ one of its RAKE receiver fingers for each received

signal.

in the uplink direction , the code channel of the mobile station is received

in each sector, then routed to the same baseband Rake receiver and the

maximal ratio combined there in the usual way.

¡

B SSector 1 f1

Sector 2 f1

Sector 3

f1

Multipath Signal through Sector 1

Multipath Signal through Sector 3



Generally we can distinguish between intra-cell handover and inter-cell handover.

For UMTS the following types of handover are specified:

Handover 3G -3G (i.e. between UMTS and other 3G systems)

FDD soft/softer handover

FDD inter-frequency hard handover

FDD/TDD handover (change of cell)

TDD/FDD handover (change of cell)

TDD/TDD handover

Handover 3G - 2G (e.g. handover to GSM)

Handover 2G - 3G (e.g. handover from GSM)

The most obvious cause for performing a handover is that due to its movement a

user can be served in another cell more efficiently (like less power emission, less

interference). It may however also be performed for other reasons such as system

load control.

The different types of air interface measurements are:

Intra-frequency measurements: measurements on downlink physical

channels at the same frequency as the active set. A measurement object

corresponds to one cell.

Inter-frequency measurements: measurements on downlink physical

channels at frequencies that differ from the frequency of the active set. A

measurement object corresponds to one cell.

Inter-RAT measurements: measurements on downlink physical channels

belonging to another radio access technology than UTRAN, e.g. GSM. A




Traffic volume measurements: measurements on uplink traffic volume. A


Q uality measurements: Measurements of downlink quality parameters,

e.g. downlink transport block error rate. A measurement objectcorresponds to one transport channel in case of BLER. A measurement

object corresponds to one timeslot in case of SIR (TDD only).

UE-internal measurements: Measurements of UE transmission power and

UE received signal level.

UE positioning measurements: Measurements of UE position.

The UE supports a number of measurements running in parallel. The UE

also supports that each measurement is controlled and reported

independently of every other measurement.





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