General Packet Radio Service

Presented By:

Kusum BhartiKusum Bharti082112103082112103

Maulana Azad National Institute of Technology,BhopalDepartment of Computer Science & Engineering

Guided By:Mrs. NAMITA TIWARI

Topics coveredTopics covered GPRS introductionGPRS introduction Goals of GPRSGoals of GPRS Goals of GPRSGoals of GPRS Network ElementsNetwork Elements Protocol Stack Protocol Stack Data Packet RoutingData Packet Routing Quality of service Quality of service Data Packet RoutingData Packet Routing GPRS - Network Processes GPRS - Network Processes Applications of GPRSApplications of GPRS Benefits of GPRSBenefits of GPRS Limitation of GPRSLimitation of GPRS ConclusionConclusion

Constraints with existing Constraints with existing networknetwork

Data Rates too slow – about 9.6 kbps.Data Rates too slow – about 9.6 kbps.

Connection setup time too long.Connection setup time too long.

Inefficient resource utilization for bursty traffic.Inefficient resource utilization for bursty traffic.

Proves expensive for bursty traffic utilization.Proves expensive for bursty traffic utilization.

No efficient method for packet transfersNo efficient method for packet transfers

What is GPRS ?What is GPRS ?

General Packet Radio Service (GPRS) is a new bearer service for GSM that greatly improves and simplifies wireless access to packet data networks

GPRS applies packet radio principal to transfer user data packets in an efficient way b/w MS & external packet data network .

Comparison of GSM & GPRSComparison of GSM & GPRS

GSMGSM GPRSGPRS

Data RatesData Rates 9.6 Kbps9.6 Kbps 14.4 to 115.2 14.4 to 115.2 KbpsKbps

Identified byIdentified by MSISDN (phone MSISDN (phone no.) no.)

IP addressIP address

Billing Billing Duration of Duration of connectionconnection

Amount of data Amount of data transferredtransferred

Operation stateOperation state oneone threethree

Type of Type of ConnectionConnection

Circuit – Switched Circuit – Switched TechnologyTechnology

Packet - Switched Packet - Switched TechnologyTechnology

Goals of GPRSGoals of GPRS

Open architectureOpen architecture Consistent IP service.Consistent IP service. Same infrastructure for different air interface.Same infrastructure for different air interface. Integrated telephony and internet infrastructure .Integrated telephony and internet infrastructure . Service innovation independent of infrastructureService innovation independent of infrastructure..

GPRS ClassesGPRS Classes

Class AClass A Class BClass B Class cClass c

GSM to GPRSGSM to GPRS

ElementElement SoftwareSoftware HardwareHardware

MSMS Upgrade req.Upgrade req. Upgrade req.Upgrade req.

BTSBTS Upgrade req.Upgrade req. No changeNo change

BSCBSC Upgrade req.Upgrade req. Pcu interfacePcu interface

MSC/VLRMSC/VLR Upgrade req.Upgrade req. No changeNo change

HLRHLR Upgrade req.Upgrade req. No changeNo change

HLR (Home location Register)HLR (Home location Register) Shared database with GSMShared database with GSM

Is enhanced with GPRS subscriber data and routing Is enhanced with GPRS subscriber data and routing informationinformation

For all users registered with the network,HLR keep For all users registered with the network,HLR keep user profile, current SGSN and packet data user profile, current SGSN and packet data protocol(PDP) addresses informationprotocol(PDP) addresses information

SGSN exchanges information with HLR e.g. inform SGSN exchanges information with HLR e.g. inform HLR of the current location of the MS.HLR of the current location of the MS.

When MS register with a new SGSN,the HLR sends When MS register with a new SGSN,the HLR sends the profile to the new SGSNthe profile to the new SGSN

VLR(Visitor Location Register) VLR(Visitor Location Register)

VLR is responsible for a group of location areas. It VLR is responsible for a group of location areas. It stores data of only those users in its area of stores data of only those users in its area of responsibility.responsibility.

MSC/VLR can be enhanced with function and MSC/VLR can be enhanced with function and register entries that allow efficient coordination register entries that allow efficient coordination between GPRS and GSM servicesbetween GPRS and GSM services

combine location updatescombine location updates

combine attachment procedurescombine attachment procedures

GPRS Network ElementsGPRS Network Elements

GPRS Architecture is same as GSM except few GPRS Architecture is same as GSM except few hardware modifications :hardware modifications : GPRS includes GSNsGPRS includes GSNs

SGSN : Serving GPRS Support NodeSGSN : Serving GPRS Support NodeGGSN : Gateway GPRS Support NodeGGSN : Gateway GPRS Support Node

GPRS RegisterGPRS Register

GGSN – Gateway GPRS GGSN – Gateway GPRS Support NodeSupport Node

• Interfaces GPRS backbone network & external packet data Interfaces GPRS backbone network & external packet data networksnetworks

• Converts the GPRS packets from SGSN to the PDP formatConverts the GPRS packets from SGSN to the PDP format

• Converts PDP addresses change to GSM addresses of the Converts PDP addresses change to GSM addresses of the destination userdestination user

• Stores the current SGSN address and profile of the user in Stores the current SGSN address and profile of the user in

its location registerits location register

• Performs authenticationPerforms authentication

• Many-to- many relations among SGSNs & GGSNs Many-to- many relations among SGSNs & GGSNs

SGSN – Serving GPRS SGSN – Serving GPRS Support NodeSupport Node

• Delivers data packets to mobile stations & vice-Delivers data packets to mobile stations & vice-versaversa

• Detect and Register new GPRS MS in its serving Detect and Register new GPRS MS in its serving areaarea

• Packet Routing, Transfer & Mobility ManagementPacket Routing, Transfer & Mobility Management

• Authentication, Maintaining user profilesAuthentication, Maintaining user profiles

• Its location register stores location info. & user Its location register stores location info. & user profilesprofiles

GPRS RegisterGPRS Register

Maintains the GPRS subscriber data and Routing Maintains the GPRS subscriber data and Routing information.information.

Stores current SGSN address.Stores current SGSN address.

GPRS Register is integrated with GSM-HLRGPRS Register is integrated with GSM-HLR

InterfacesInterfaces Gn – SGSN – SGSN/GGSN (in the same network).Gn – SGSN – SGSN/GGSN (in the same network). Gp – SGSN –GGSN (in different networks).Gp – SGSN –GGSN (in different networks).

Gi – Connects PLMN with external Packet Data Gi – Connects PLMN with external Packet Data Networks (PDNs).Networks (PDNs).

Gf – For equipment querying at registering timeGf – For equipment querying at registering time

Gr – To exchange User profile between HLR & SGSNGr – To exchange User profile between HLR & SGSN

Gs – To exchange Database between SGSN & MSCGs – To exchange Database between SGSN & MSC

Gd – Interface between SMS & GPRSGd – Interface between SMS & GPRS

Gb – Connects BSC with SGSN.Gb – Connects BSC with SGSN.

GPRS architecture reference modelGPRS architecture reference model

SGSN

GGSNBSC

MSC

SGSN PDN

VLR EIR

HLR

MSUM

Gb Gn

Gn

GiGs

Gr

Gf

Gc

Protocol StackProtocol Stack

GSM RF

SNDCP

IP / X.25

Application

Um GnGb

MAC

RLC

LLC

IP / X.25

GTP

L1

L2

LLC

GSM RF

FrameRelay

MAC

RLC BSSGP

L1bis

BSSGPFrameRelay

LLC

SNDCP GTP

L1bis L1

L2

IP

MS BSS (PCU) SGSN GGSN Gi

IP

UDP/TCP

UDP/TCP

Data Link layerData Link layer

Divided into two sub layers :Divided into two sub layers : LLC layer (between MS-SGSN)LLC layer (between MS-SGSN)

RLC/MAC (between MS-BSS)RLC/MAC (between MS-BSS)

LLC-Logical Link ControlLLC-Logical Link Control

Establishes highly reliable logical link between MS & its Establishes highly reliable logical link between MS & its assigned SGSNassigned SGSN

Works either in acknowledged or unacknowledged Works either in acknowledged or unacknowledged modesmodes

Data confidentiality is ensured by ciphering functionsData confidentiality is ensured by ciphering functions

RLC/MAC LayerRLC/MAC Layer Radio Link Control(RLC)Radio Link Control(RLC)

Establish a reliable link between MS & BSS Establish a reliable link between MS & BSS Medium Medium Access Control(MAC)Access Control(MAC)

Segmentation and reassembly of LLC frames into RLC data Segmentation and reassembly of LLC frames into RLC data blocksblocks

Medium Access Control(MAC)Medium Access Control(MAC) Controls access attempts of an MS on radio channels shared by Controls access attempts of an MS on radio channels shared by

several MSsseveral MSs

Both ack and unpack. Modes of operation are supported in Both ack and unpack. Modes of operation are supported in RLC/MAC layerRLC/MAC layer

Physical LayerPhysical Layer

Divided into two sub layers :Divided into two sub layers : 1. 1. Physical Link Layer (PLL)Physical Link Layer (PLL)

2. Physical RF Layer (RFL)2. Physical RF Layer (RFL)

PLL – Provides a physical channel between MS PLL – Provides a physical channel between MS and BSS and BSS

RFL - Operates below PLLRFL - Operates below PLL

SNDCP-Sub Network DependentSNDCP-Sub Network DependentConvergence ProtocolConvergence Protocol

Used to transfer data packets between SGSN and Used to transfer data packets between SGSN and MS.MS.

Multiplexing of several connection of network Multiplexing of several connection of network layer onto one logical connection of underlying layer onto one logical connection of underlying LLC layer.LLC layer.

Compression and decompression of user data and Compression and decompression of user data and header informationheader information

BSSGP-(BSS GPRS Application BSSGP-(BSS GPRS Application Protocol)Protocol)

Delivers routing & Quality of Service related information Delivers routing & Quality of Service related information between BSS and SGSNbetween BSS and SGSN

Data Packet RoutingData Packet Routing

Mobile oriented messageMobile oriented message

Network initiated message when MS is in homeNetwork initiated message when MS is in home

Network initiated message when MS roam to Network initiated message when MS roam to another GPRS networkanother GPRS network

When MS is transmittingWhen MS is transmitting At MS,IP datagram is compressed and At MS,IP datagram is compressed and

encapsulated into an SNDCP ,that is sent through encapsulated into an SNDCP ,that is sent through LLC,RLC/MAC and RF to the serving GSN.LLC,RLC/MAC and RF to the serving GSN.

When SGSN receives the data, it tunnels the When SGSN receives the data, it tunnels the packet to the reference GGSN through the GPRS packet to the reference GGSN through the GPRS backbone.backbone.

GGSN removes the tunneling and forward the IP GGSN removes the tunneling and forward the IP datagram to the internet that delivers the data to datagram to the internet that delivers the data to final destination.final destination.

When MS is receivingWhen MS is receiving The corresponding host sends the IP datagram to The corresponding host sends the IP datagram to

a GPRS MS using the MS’IP address.a GPRS MS using the MS’IP address.

Internet routing protocols are used to route data Internet routing protocols are used to route data to MS’ subnetwork.to MS’ subnetwork.

GGSN extracts MS’s IP address and maps it to GGSN extracts MS’s IP address and maps it to MS’s current location.MS’s current location.

GGSN tunnels the packet through the GPRS GGSN tunnels the packet through the GPRS backbone to the SGSN serving the MS.backbone to the SGSN serving the MS.

Contd.Contd.

SGSN removes the tunneling,encapsultes the IP SGSN removes the tunneling,encapsultes the IP datagram into an SNDCP and forwards it to BSS.datagram into an SNDCP and forwards it to BSS.

Packet is sent to MS through LLC,RLC/MAC and RFPacket is sent to MS through LLC,RLC/MAC and RF

When MS is in roamingWhen MS is in roaming

MS from PLMN-2 is visiting PLMN-1MS from PLMN-2 is visiting PLMN-1 IP address prefix of MS is the same as GGSN-2IP address prefix of MS is the same as GGSN-2 Incoming packets to MS are routed to GGSN-2Incoming packets to MS are routed to GGSN-2 GGSN-2 queries HLR and find that MS is currently in GGSN-2 queries HLR and find that MS is currently in

PLMN-1PLMN-1 It encapsulates the IP packets and tunnels them It encapsulates the IP packets and tunnels them

through the GPRS backbone to the appropriated through the GPRS backbone to the appropriated SGSN of PLMN-1SGSN of PLMN-1

SGSN decapsulates and delivers to MS.SGSN decapsulates and delivers to MS.

DATA CALL ROUTING

inter-PLMN

GPRS backbone

External Packet data network(PDN)

Intra-PLMN

GPRS backbone

intra-PLMN

GPRS backbone

PLMN1

PLMN2

SGSN

SGSNSGSN

GGSNGGSN

Border gatewayBorder

gateway

Gp

GnGi

Gn

Gn

BTS BTS

BSCBSC

HostRouter

LAN

MS

SESSION SESSION MANAGEMENT IN GPRSMANAGEMENT IN GPRS

Attachment & Detachment Attachment & Detachment ProcedureProcedure

GPRS attachGPRS attach User is registered in SGSN, after User is registered in SGSN, after

authentication check from HLRauthentication check from HLR

GPRS detachGPRS detach Disconnection of MS from GPRS network is called Disconnection of MS from GPRS network is called

GPRS detachGPRS detach It can be initiated by MS or by network(SGSN or It can be initiated by MS or by network(SGSN or

HLR)HLR)

Session ManagementSession Management Mobile Station applies for PDP addressMobile Station applies for PDP address

For each session For each session PDP contextPDP context is created & it contains is created & it contains PDP typePDP type PDP address assigned to MSPDP address assigned to MS Requested QoSRequested QoS Access pointAccess point

With active PDP context MS able to send or receive With active PDP context MS able to send or receive data packetsdata packets

Allocation of PDP address can be static or dynamicAllocation of PDP address can be static or dynamic

PDP Context ActivationPDP Context Activation

MS SGSN GGSNMS SGSN GGSN

Activate PDP Context Request

Security Functions

Activate PDP Context Accept

Create PDP Context Request

Create PDP Context Response

PDP type,PDP AddressQoS Requested,Access Point,…

PDP type,PDP AddressQoS Negotiated,Access Point,…

PDP type,QoS Negotiated,…PDP type,PDP AddressQoS Negotiated,…

LOCATION LOCATION MANAGEMENT IN GPRSMANAGEMENT IN GPRS

State Model of GPRS MSState Model of GPRS MS

GPRS - Network ProcessesGPRS - Network Processes

Attach process: Attach process: Authentication process: Authentication process: PDP activation process: PDP activation process: Detach process: Detach process: Network-initiated PDP request for static IP Network-initiated PDP request for static IP

address: address: Network-initiated PDP request for dynamic IP Network-initiated PDP request for dynamic IP

address: address:

Quality of serviceQuality of service

Service Precedence: Service Precedence: Reliability: Reliability: Probability of lossProbability of loss Duplication Duplication Mis-sequencingMis-sequencing Corruption of packetCorruption of packet

DelayDelay ThroughputThroughput

Applications of GPRSApplications of GPRS

Web browsingWeb browsing Corporate & Internet Email Corporate & Internet Email Still ImagesStill Images Remote LAN AccessRemote LAN Access Home AutomationHome Automation Document Sharing/Collaborative workingDocument Sharing/Collaborative working MobilityMobility Immediacy Immediacy LocalizationLocalization

GPRS in INDIAGPRS in INDIA

•Hutchison Essar•Idea Cellular•Hutchison Max•Bharti Cellular•BPL Mobile•Reliance Mobile

Benefits of GPRSBenefits of GPRS

New Data Services.New Data Services. High Speed (Data Rate 14.4 – 115 kbps).High Speed (Data Rate 14.4 – 115 kbps). Efficient use of radio bandwidth .Efficient use of radio bandwidth . Circuit switching & Packet Switching can be Circuit switching & Packet Switching can be

used in parallel.used in parallel. Constant connectivity.Constant connectivity. Easy Billing.Easy Billing.

Limitation of GPRSLimitation of GPRS

Limited cell capacity for all usersLimited cell capacity for all users Speed much lower in realitySpeed much lower in reality Transit delaysTransit delays No store and forwardNo store and forward

ConclusionConclusion

To sum up, GPRS improves the utilization of the To sum up, GPRS improves the utilization of the radio resources, offers volume-based billing, radio resources, offers volume-based billing, higher transfer rates, shorter access times, and higher transfer rates, shorter access times, and simplifies the access to packet data networks.simplifies the access to packet data networks.

What is Next ? What is Next ?

Enhanced Data rate for GSM Evolution (EDGE): Enhanced Data rate for GSM Evolution (EDGE): Universal Mobile Telecommunication System Universal Mobile Telecommunication System

(UMTS): (UMTS):

Thank youThank you