waleed- gprs

8/7/2019 waleed- gprs

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GSM Evolution

Speech FR,

standard services

Data: max. 9,6kbit

Speech HR,

multipleSupplementary

Services (SS)

comparable to ISDN


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GSMPhase 2+y Improved speech quality

y New speech code(EFR)

y World Wide availabilityy Data transmission in GSM phase2+

y HSCSD

y GPRS

y EDGE


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High speed circuit switched datay New coding scheme

y Point -to-point call

y TR rati up to 115.2kbpsy Applicationwith higher BW

y Small hardware modification over GSM

y More than one time slot for the user


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General Packet Radio Servicesy Packet switching

y Four new coding scheme

(cs-1 9.05 , cs-213.4 , cs-315.6 , cs-421.4)kbpsy TR up to 171.2kbps

y Point-to-multipoint

y Fast set up&low cost

y Conectivity to other data networks(IP,X.25)


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Enhanced Data Rate for GSM

Evolution uses a new modulation method:

replaces GMSK by 8PSK

three bit of information can be transportedby one symbol of modulation (instead of one bit)

BTS has to be upgraded

hardware modifications are necessary

will possibly used only DL in the introduction phase

cheap mobile phones

asymmetric data rates in UL and DL


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GPRS SERVICESy

GPRS SERVICES divided to three main groupsPint to point services

Point to multipoint services

Additional and value added services


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Point-to-Point Services (PTP)


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-Points-to-Multipoint Services (PTM)Sending data to multiple dest within one single servicerequest and divided to

The Point-to-Multipoint Multicast

The Point-to-Multipoint roup all

Internet Protocol Multicast


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- Point-to-Multipoint Multicast

sender sends out information to severalreceivers in a defined area

No paging ,No need to be attached No Confirmations The sender does not know who has receivedinformation Repeated sending No ciphering is used One way connection


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Point-to-Multipoint Group

All receivers are selected and located within acertain area They must be GPRS-attached Ciphering Receivers can now send back data The n-way connection conference


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Internet Protocol Multicast- A service based on Internet Protocol The receiver group can be located within a mobile phonenetwork, or anywhere in the Internet


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Supplementary and value-added services

- Unidirectinal forwarding of calls

- forwarding of calls when participant is not

reachable

- Closed user group

- Charge information


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- Access to data networks like the Inter-and Intranet,

- Reading of fax and email,

- Receiving breaking news and completenewspaper contents

- Getting the latest traffic informationfor a planned trip

- Messages of commercial interest.


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Quality of service Priority classes

Divided to (high, middle, low) according the need ofthe user

The maximum and average guaranteed transmissionrate

Adjust to the network capacity and the demand ofthe user


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y The maximum time of delay.

Three classes of maximum accepted delay rates


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Mobile Stationsy

There are three classes for MSClass ccan use GSM&GPRS but only one service at

time the service not used is deactivated

Class B parallel monitor mechanism

Class A support & use both service simultaneosly


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GPRS - Architecture

Channel CodecUnit CCU

Mobile

DTE

SGSN

PSTN

InternetIntranet

X.25

GGSN

VMSC /VLR

GMSC

HLR

SGSN(access to BSS)

GGSN(access to PDN)

ISDN

PCU

BSS

Packet ControlUnit PCU


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Serving GPRS Support Node SGSN

serves MSs in SGSN areay Mobility Management functions, e.g

Update Location, Attach, Paging,..y Security and access control:

Authentication, Cipher setting, IMEI Check...

New cipher algorithmy Routing / Traffic-Managementy collecting charging datay realises Interfaces: Gn, Gb, Gd, Gp, Gr, Gs, Gfy

controls subscribers in its service area (SLR)


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SGSN

Enable the exchange of data between themobile station and the GGSN

It includes the address of the BSS, where theGPRS user is located

Ciphering function

- The cause of early ciphering in the GPRS network the security of the transmission increases

it will not be necessary to reconfigure allexisting Base Transceiver Stations thusreducing the costs of integrating the GPRSservice


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Gateway GPRS support nodey Provide the interface between the external(

IP,X.25) packet networks

y Protocol conversiony Support addressing mapping

y Creation the routing table

y

Routing to the right SGSNy Tunneling

y screening


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y MSC/VLR

User location

y HLR

User information

y BSC

Packet control unit

y BTS

New protocol for the air interface


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Packet control unit

y ThePCU can be implemented in:

the Base Transceiver Station

the Base Station Controller one of the two GPRS Support Nodes


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y Mangment for radio channel

y Congestion control

y Power control

y Broad cast control information

y

Serves for protocol conversiony It has channel access control function access request

and grant


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Cooperation between GSM GPRS Elements


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Connection Management


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Some applications of GPRSy CHAT

y Textual and visual information

y Web Browsingy Vehicle Position

y Remote LAN access

y File Transfer

y Home Automation


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Coding scheme


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PACKET HANDLING


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Measurment accuracyy It is essential to analyse the radio link quickly in order

to adapt the coding to the new environment

y

In GPRS is performed only during idle bursts twiceevery 240ms

y In EDGE measurements are taken on every burst thisresult in high accuracy


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EDGE Benefitsy Capacity and performance

y Cost effect and easy to implement

y Triples the capacity of GPRSy Enable new application attract the subscriber

y Operators can offer more than wireless dataapplication including multimedia ,e-mail , web

informationy Subscribers will be able to browse the internet


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GPRS vs EDGEy EDGE is added on GPRS

y EDGE&GPRS have difrent protocol in BSS sharing the

same protocol in the networky EDGE mskes it easier for circuit switched &packet

switched to coexist

y More efficient to use radio rasources

y Can transmit three times as many as GPRS


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GPRS Procedures

THE END

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waleed- gprs