GPRS Introduction

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GPRS

NISHI BHANU PRATAP SINGHELECTRONICS AND COMMUNICATION EN-

GINEERING

GALGOTIAS COLLEGE OF ENGINEERING &

TECHNOLOGY, GREATER NOIDA

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General Overview

► GPRS stands for General Packet Radio System. GPRS provides packet radio access for mobile GSM and TDMA users.

► The GPRS specifications are written by the European Telecommunications Standard Institute (ETSI), the European counterpart of the American National Standard Institute (ANSI).

► GPRS is a Mobile Data Service available to users of GSM and IS-136 mobile phones.

► GPRS is packet-switched and multiple users share the same transmission channel for transmitting the data.

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GPRS is important as a migration step toward third-generation (3G) networks and allows network oper-ators to implement an IP-based core architecture .

GPRS is a new bearer service for GSM that greatly improves and simplifies wireless access to packet data networks.

Networks based on the Internet Protocol and X.25 networks are also supported in the current versions of GPRS.

GPRS Overview 4GPRS Overview 4

Basic GSM System Architecture

BTSBTS

BTSBTS

BTSBTS

BTSBTS

BTSBTS

BTSBTS

BSCBSC

BSCBSC

MSCMSC

HLRHLR VLRVLR AUCAUC

OMCOMC

PSTNPSTN

ISDNISDN

CSPDNCSPDN

PSPDNPSPDN

MS

MS

UmAbis

A

TETE

GPRS Overview 5

Basic GPRS System Architecture

BTSBTS BSCBSC

SGSNSGSN

MSC/VLRMSC/VLR HLRHLR

IPIP

X.25X.25

MS

MS

BSSUm

TETE

GGSNGGSN

PCUPCU

BTSBTS BSCBSC PCUPCU

Gs Gr

GnGb


GPRS Transmission Plane

MS

Relay

NetworkService

GTP

Application

IP / X.25

SNDCP

LLC

RLC

MAC

GSM RF

SNDCP

LLC

BSSGP

L1bis

RLC

MAC

GSM RF

BSSGP

L1bis

Relay

L2

L1

IP

L2

L1

IP

GTP

IP / X.25

Um Gb GnGi

MS BSS SGSN GGSN

NetworkService

UDP /TCP

UDP /TCP

MS

Gb GnSGSNSGSN GGSNGGSNBTSBTS BSCBSC PCUPCU


GPRS Logical Channel

Downlink& Uplink

Downlink Uplink

Downlink

Downlink

Downlink

Logical ChannelLogical Channel

Signaling ChannelsSignaling Channels

Packet Traffic Channel

Packet Traffic Channel

Packet Broadcast Control Channel

Packet Broadcast Control Channel

Packet Common Control Channel

Packet Common Control Channel

PDTCHPDTCH

PACCHPACCH

PBCCHPBCCH PRACHPRACH

PPCHPPCH

PAGCHPAGCH

PNCHPNCH

Traffic ChannelsTraffic Channels

GPRS Overview 8


SGSN : The Serving GPRS Support Node (SGSN)– Same hierarchical level as the MSC– Serves attached mobiles– keeps track of the individual MSs' location and performs

security functions and access control.– Connected to the BSS with Frame Relay(in future, ATM)– Data/packet Counting(for charging)

GPRS Overview 9


GGSN : The Gateway GPRS Support Node – Interworking with external packet-switched networks – Connected with SGSNs via an IP-based GPRS backbone

network. – The HLR is enhanced with GPRS subscriber information– Enhanced MSC/VLR : co-ordination of GPRS and non-

GPRS services (paging , LA)

PCU : Packet Control Unit– Packet Segmentation– Radio Channel Allocation– QoS measurements

GPRS Overview 10

GPRS Attach/Dettach

Establishes a logical link between the MS and the SGSN

Performed when a mobile indicates its presence to the network, for the purpose of using the ser-vices provided by the network

Dependent upon the class of the mobile– IMSI attach for GSM circuit switched(CS) services– GPRS attach– Combined IMSI/GPRS attach

GPRS Overview 11

PDP Context Activation

PDP Context – Contains mapping and routing information btw. MS &

GGSN– Activation

Allocation of PDP Address Access point name(APN) Quality of service required(QoS)

– Priority (for packet transfer)– Reliability (of connection, I.e. loss of data)– Delay (within the network)– Throughput (data/time)

GPRS Overview 12

GPRS Mobile States

GPRSAttach

GPRSDettach

Ready timer expiry or

Force to StandbyPDU Transmission

IdleIdle

ReadyReady

StandbyStandby

GPRS Overview 13

GPRS Mobile Class

Modes of operation

Either GPRS or GSM ser-vices

Both GPRS and GSM ser-vices

Both GPRS and GSM ser-vices

Attached to

Alternate use onlyClass C

Only operate one set of ser-vices at a timeClass B

Simultaneous attach • monitor • traffic

Class A

SupportMode

GPRS Overview 14

GPRS Operation

1. GPRS Attach

2. PDP Activation

Encapsulation & Tun-neling

PDNs

GPRS Attach makes the MS known in the corresponding GGSN

PDP Activation establishes a logical link between MS and SGSN

Encapsulation & Tunneling data Packets are equipped with GPRS-specific protocol information and transferred between MS and GGSN

3. Data Transfer

Gb GnSGSNSGSN GGSNGGSNBTSBTS BSCBSC PCUPCU

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Applications

► Communications: E-mail, fax, unified messaging and in-tranet/Internet access etc.

► Value-added services: Information services and games etc.

► E-commerce: Retail, ticket purchasing, banking and financial trading etc.

► Location-based applications: Navigation, traffic conditions, airline/rail schedules and location finder etc.

► Vertical applications: Freight delivery, fleet management and sales-force automation.

► Advertising: Advertising may be location sensitive. For ex-ample, a user entering a mall can receive advertisements specific to the stores in that mall.

GPRS Overview 16

Thank you

GPRS Introduction

Engineering

Transcript of GPRS Introduction