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Mohamed M.DiefProf : Shawky Shaban

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H istory Of GSMThe Goals of GSMGSM Cell Structure

Types of CellsCellular principlesGenerationsGSM ArchitecturesMultiple Access SchemesGPRSUMTSLTE

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Early 1980s there was analog technologies

Advanced Mobile Phone Services(AMPS)in North America.

Total Access Communications System(TACS) in the UK.

Nordic Mobile Telephone(NMT) in Nordic countries.

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Each country developed its own system, which caused problems:

System worked only within the boundaries of each country.

Mobile equipment manufacturers markets were limited by theoperating system.

Solution was GSM, which is digital technology and wasdeveloped by CEPT(Conference of European Posts andTelecommunications).

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Improved spectrum efficiency.

International roaming.

Low-cost mobile sets and base stations.

H igh-quality speech.

Compatibility with ISDN and other telephone.

Company services.

Support for new services.

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Used in over 170 countries

Over 400 GSM network operators

Over 1.5 Billion people were subscribers to GSM

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The power level of atransmitter within asingle cell must belimited to reduce theinterference with theneighboring cells.

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Neighboring cells cannotshare the same channels

Different size of

patterns: 4, 7, 12 or 21cells in one cluster

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Macrocells (3 to 35 km)

Microcells(0,1 to 1 km)

Picocells (0,01 to 1km)

Nanocells (1m to 10m)

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Selective cells and tieredcells(two sectors, twofrequencies)

Umbrella cells :- covers several microcells

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Frequency reuse same frequency inmany cell sites

Cellular expansion easy to add new cells

H andover moving between cells

Roaming between networks

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Analog [routines for sending voice]

All systems are incompatible

No international roaming

Little capacity cannot accommodate masses of subscribers

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Digital [voice encoding]

Increased capacity

More security

Compatibility

Can use TDMA for increasing capacity

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Packet-Switching

Connection to the internet is paid by packets and not by

connection time.

Connection to internet is cheaper and faster [up to 56KBps]

The service name is GPRS General Packet Radio Services

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Permanent web connection at 2Mbps

Internet, phone and media: 3 in 1

The standard based on GSM is called UMTS

The EDGE standard is the development of GSM towards 3G.

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Mobile stationMS SIM PH ONE

BTS BTS

BSC BSC

H LR

AuC EIR

VLR

Base Station subsystem

BSS

NetworkSwitchingSubsystem NSS

MSC

PLMN, PSTN, ...

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B ase Station Controller( B SC)

Translates the 13-Kbps voice to the standard 64-Kbps channel(used by PSDN or ISDN)

Frequency hopping

Time and frequency synchronization

Power management

Time delay measurements

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The Transcoder andadaptation unit(TRAU)

(13Kbps speech or data+ 3Kbps additionalsynchronizing data)*4=64Kbps (TRAUStandard rate)

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Base StationSubsystem(BSS)= BTS + BSC

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M obile Switching Center( M SC)

The central component of the Network Subsystem

(30 + 2)* 64Kbps = 2,048Mbps(E1) or better to the other networkinterfaces(PSDN,ISDN)

Billing

Location registration

Gateway to SMS

Synchronizing BSS

H andover management

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GSM uses TDMA and FDMA to let everybody talk.

FDMA: 25MH z freq. is divided into 124 carrier frequencies.Each base station gets few of those.

TDMA: Each carrier frequency is divided into bursts [0.577 ms].8 bursts are a frame.

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Frequency hopping

216,7 hops/second

After each burst frequency changed according to predefined pattern

Spreads disturbances

Makes eavesdropping more difficult

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Updating location

Uses MSC,H LR and VLR

When MS moves to new location area or to new operator area -> mustregister for update

Location update message to new MSC/VLR pair that registers newinformation and sends it to subscribers H LR.H LR sends the previous VLRinformation that subscriber left its area

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Frequency Division Multiple Access (F DMA), different frequencies fordifferent users

example Nordic Mobile Terminal (NMT) systemsTime Division Multiple Access (TDMA), same frequency but different timeslotsfor different users,

example Global System for Mobile Communication (GSM)GSM also uses FDMA

Code Division Multiple Access (CDMA), same frequency and time but users

are separated from each other with orthogonal codes

FDMAFDMA TDMATDMA CDMACDMA

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General Packet Radio Serves.GPRS is devolved from GSM by introducing two new corenetwork nodes SGSN and GGSN

Existing GSM nodes(BSS,MSC/VLR andH LR) are upgradedConcept foresees bit rates of nearly 170kb/sSeveral users can use the same channel simultaneouslyAlways on line

Radio resource allocationCharging is based on amount of transmitted dataNo need to access H LR for every GPRS packet

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Universal Mobile Telecommunications System

Air Interface based on W-CDMA

H igh Speed Data ServicesCS domain: up to 384 kbpsPO domain: up to 2 Mbps

2 different Modes: FDD-mode, TDD-mode

CommonInterface for CS and PO between Access NW and Core NW

H andover between RNCs in Access NW

Enhanced Security Functions

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Radio NetworkControlRNC

UMSC

Iub Interface Iu Interface

Radio NetworkControlRNC

Iub Interface Iu Interface

Iur Interface

Node B

Node B

A N

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Significantly increase peak data rates, scaled linearly according to spectrumallocation

improving spectral efficiency

lowering costs

improving services

making use of new spectrum opportunities

Improved quality of service

better integration with other open standards

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D ata Rate:Instantaneous downlink peak data rate of 100Mbit/s in a 20M H z downlinkspectrum (i.e. 5 bit/s/ H z)Instantaneous uplink peak data rate of 50Mbit/s in a 20M H z uplink spectrum(i.e. 2.5 bit/s/ H z)

Cell range5 km - optimal size30km sizes with reasonable performance

up to 100 km cell sizes supported with acceptable performance

Cell capacityup to 200 active users per cell(5 M H z) (i.e., 200 active data clients)

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M obilityOptimized for low mobility(0-15km/h) but supports high speed

Latencyuser plane < 5mscontrol plane < 50 ms

Improved spectrum efficiency

Cost-effective migration from Release 6 Universal Terrestrial RadioAccess (UTRA) radio interface and architecture

Improved broadcasting

IP-optimized

Scalable bandwidth of 20M H z, 15M H z, 10M H z, 5MH z and

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