21 Gprs Principle Issue2.0

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Internal

OMQ000001 GPRS Principle

ISSUE 2.0


GPRS principle is the basic part of the

whole GPRS system and the

succeeding products learning. This slide

will help us to understand the GPRS

system networking and wireless

subsystem etc.


References

GPRS principle

31025698 - M900/M1800 PCU Technical

Manual-(V3.35)

GPRS protocol

0360

0464

GSM protocol

0816

0818


Upon completion of this course, you will

be able to:

Know the GPRS system structure

Describe the GPRS important

interfaces

Understand the GPRS channel

structures

Master the GPRS relevant numbering


Chapter 1 Chapter 1 GPRS System StructureGPRS System Structure

Chapter 2 Chapter 2 GPRS Network Interfaces & ProtocolsGPRS Network Interfaces & Protocols

Chapter 3 Chapter 3 GPRS Wireless SubsystemGPRS Wireless Subsystem

Chapter 4 Chapter 4 GPRS NumberingGPRS Numbering

Chapter 5 Chapter 5 GPRS Mobility Management (GMM)GPRS Mobility Management (GMM)


GSM Development Evolution

57.6 kbps

115 kbps

384 kbps

2 Mbps

GSM

HSCSD

GPRS

EDGE

IMT-2000

9.6 kbps

2G

2.5G

3G


What is GPRS and EDGE?

Abbreviation of General Packet Radio Service.

GPRS is an end-to-end packet switching technology provided on the basis

of GSM technology.

It has much interactive services with the existing GSM circuit switching

system.

GPRS supports wireless access rate of up to 171.2Kbps.

EDGE (Enhanced Data Rates for GSM Evolution)

EGPRS (Enhanced GPRS)

− EGPRS supports wireless access rate of up to 473.6Kbps.

ECSD (Enhanced CSD, Enhanced HSCSD-High Speed Circuit Switched Data)


Gf

GiGnGb

Gc

Gp

Gs

MSC/VLR

MS BSS TEInternet

Um

Gr

HLR

Other PLMN

SGSN

Gd

SM-SCSMS-GMSCSMS-IWMSC

GGSN

EIR

SGSN

Gn

FR

ATM/DDN/ISDN/

Ethernet, etc

BG

GPRSbackbone

GGSN X .25 TE

Gi

CGMS BSS

Um

GPRS system structure

FR

Gb

SS7


GPRS MS

Class A

The MS is attached to both GPRS and other GSM services and the MS supports simultaneous operation of GPRS and other GSM services.

Class B

The MS is attached on GPRS network and GSM network simultaneously but not enabling circuit switching and packet switching services at the same time.

services are selected automatically.Class C

The MS is attached to either GPRS or other GSM services. Alternate use only.

services are selected manually or default selected service.


Functions of GPRS BSS

Packet wireless resources management function (RLC/MAC

protocol function)

System message broadcast

Packet paging processing

Wireless channel configuration

Wireless resources allocation

Wireless link monitoring

Power control

Channel coding/decoding control

Cell rerouting control

Uplink traffic control (wireless QoS guarantee)


Functions of GPRS BSS

Gb interface processing function

Data packet relay on wireless interface and Gb interface

Mobility management (cell updating procedure)

Downlink traffic control (wireless QoS guarantee)


Packet processing functions of BTS RF processing function

Function of physical layer of wireless interface

Channel coding/decoding and adjustment

Packet logic channel mapping

time advance value self-adaptive adjustment

Uplink measurement

Downlink power control execution

G-Abis interface processing function

Transmission of RLC/MAC control block and data block

Synchronization mechanism with TDMA block of PCU

Uplink measurement report

Transmission check

Other inner-band signaling functions


Packet processing functions of BSC

Packet wireless resource management function

Packet channel configuration

TBF establishment procedure when PBCCH is not configured in the cell

Circuit paging coordination


G-Ais interface physical layer switching

Pb interface switching function

Similar to the relative functions of PCU


Functions of PCU

Packet wireless resource management function (RLC/

MAC protocol function)

Wireless resource management functions of GPRS BSS

Circuit paging coordination


Function related with GPRS BTS


Functions of PCU

Pb interface processing function

LAPD link between BSC and PCU

Layer-3 signaling between BSC and PCU

Gb interface processing function

Data packet relay on wireless interface and Gb interface

Mobility management (cell updating procedure)

Downlink traffic control (wireless QoS guarantee)


Position of PCU

CCU

CCU

CCU=Channel Codec UnitPCU= Packet Control Unit

CCUPCU

BTS BSC GSN

AGb

Um

CCU

CCUPCU

BTS BSC GSN

B

CCUPCU

BTS BSC GSN

C

Abis

Gb

Gb


Position of Huawei PCU

CCU

CCU

BSCBTS

SGSN

Um

Abis

GbBSC

Pb

CCU

CCU

PCU

BTS


GPRS(BSS side) upgrade to EDGE

Upgrade BSC software

Upgrade PCU software

upgrade BTS software and hardware - new EDGE TRX

EDGE

TRX


Functions of SGSN

Network access control (MS side)

Authentication

Billing information collection

IMEI check

Logic link management

SGSN-MS logic link management

Supporting acknowledged/unacknowledged transmission

Route management

SGSN-BSS data transmission route management

Mobility management and session management


Functions of SGSN

Route and tunnel transmission

Compression and decompression

Encryption and decryption

Storage and transfer of subscriber data

Routing: executed with PDP context

Address translation and mapping: including DNS and GGSN a

ddress induced from APN

Encapsulation and tunnel transmission


Functions of GGSN

Network access control (external PDN side)

Message filtering

Billing information collection

Mobility management and session management

Routing and transfer

Storage and transfer

Routing

Address translation and mapping

Encapsulation and tunnel transmission

Dynamic allocation of IP addresses


Functions of CG

Real-time collection of GPRS bills

Temporary storage and buffering of GPRS bills

Pre-processing of GPRS bills

Sending GPRS bills to the billing center


Functions of BG

BG enables the following protocols necessary for interworking b

etween operators

Security protocol: IPSec and firewall are recommended

Routing protocol: BGP is recommended

Billing protocol: determined by the operators with negotiation; BG mi

ght be needed in collecting billing information

It is normally based on routers

It can be configured in combination with GGSN


Functions of MSC/VLR

When Gs interface is installed, MSC/VLR can support

Establishment and maintenance of the association between SG

SN and MSC/VLR.

GPRS combined mobility management procedure.

Combined IMSI/GPRS attachment/detachment.

Combined location area/routing area updating.

Circuit paging coordination function.

The wireless resource usage can be greatly improved.


Functions of HLR/AUC

Saving and updating GPRS subscriber subscription data

User authentication

Providing location/routing information and processing needed i

n mobility management and routing, for example:

Saving and updating user service SGSN number and address

GPRS user location deletion indication

Whether MS is reachable.

Subscriber tracing (optional)


Functions of SMS-GMSC/SMS-IWMSC

After Gd interface is installed, short messages can be sent via

GPRS, which reduces the occupation on SDCCH and cuts do

wn the influence on voice services by SMS services.

The operator can select to send SMS via MSC or SGSN.


Network interface types GPRS backbone netwo

rk

SGSNSGSN

SGSNSGSNGGSNGGSNGn

IP interface

SS7 interface

BSS MSCSMS-GMSC

AUm

PDP network (IP/X.25)

Gi

TE

MT

MS

HLR

Gs

Gr

Gd

Gc

Gb


Data transmission plane

MAC: Media Access Control

RLC: Radio Link Control

LLC: Logical Link Control

BSSGP: BSS GPRS Protocol

SNDCP: Sub-Network Dependency Convergence Protocol

GTP: GPRS Tunneling Protocol

Application

IP/X.25 IP/X.25 IP/X.25

SNDCP GTP

LLC LLC UDP/TCP UDP/TCP

RLC BSSGP BSSGP IP IP

MAC MACNetworkService Network

ServiceL2 L2

L2 (MAC)

PhysicalLayer

PhysicalLayer

PhysicalLayer

PhysicalLayer

PhysicalLayer

PhysicalLayer

PhysicalLayer

MS BSS SGSN GGSN

relay

relaySNDCP GTP

Um Gb Gn Gi

RLC


MS-SGSN signaling plane

GMM: GPRS Mobility Management

SM: Session Management

MS BSS SGSN

BSSGP

GMM/SM

LLC

RLC

MAC

GSM RF

GMM/SM

LLC

BSSGP

L1bis

Um Gb

NetworkService

RLC

MAC

GSM RF L1bis

NetworkService

Relayrelay


Functions of physical layer

Physical layer consists of RF sub-layer and physical link sub-layer

RF sub-layer

− modulation and demodulation.

Physical sub-layer

− error check, interleaving.

− Radio channel measurement, including receiving signal level and quality

measurement, TA measurement, physical link layer congestion

measurement.

− Radio management function, including cell selection and reselection

procedures, power control procedure of transmitter, battery power

management procedure, such as DRX.


Functions of RLC/MAC RLC/MAC layer service

The RLC/MAC function supports two modes of operation

− Unacknowledged operation

− Acknowledged operation

RLC/MAC layer functions

The RLC function defines the procedures for segmentation and reassemble

of LLC PDUs into RLC/MAC blocks and, in RLC acknowledged mode of

operation, for the Backward Error Correction (BEC) procedures enabling the

selective retransmission of unsuccessfully delivered RLC/MAC blocks.

The MAC function defines the procedures that enable multiple mobile stations to share

a common transmission medium, which may consist of several physical channels. The

function may allow a mobile station to use several physical channels in parallel, i.e. use

several timeslots within the TDMA frame.


NS layer definition

The Network Service performs the transport of NS SDUs(Service Dat

a Unit ) between the SGSN and BSS.

The Network Service entity is composed of the Sub-Network Service

and the Network Service Control.

Network Service Control /

Network Service Control Protocol

Sub-Network Service /

Sub-Network Service Protocol

Network Service


NS layer composition The Network Service Control

− the peer-to-peer communication between remote NS user entities is

performed over BSSGP Virtual Connections (BVCs).

− A BVC is a virtual communication path between Network Service user peer

entities.

The Sub-Network Service

− The Network Service Control peer entities use the Sub-Network Service for

communication with each other.

− The peer-to-peer communication across the Gb interface between remote

Network Service Control entities is performed over Network Service Virtual

Connections (NS-VCs).

− An NS-VC is a virtual communication path between Network Service Control

peer entities.


Functions of NS NS is responsible for

NS SDU transmission

− The NS SDUs shall be transmitted on the NS-VCs. The NS SDUs are encapsulated into Network Service Control PDUs which in turn are encapsulated into Sub-Network Service PDUs.

Load sharing

− The load sharing function distributes the NS SDU traffic amongst the available (i.e. unblocked) NS-VCs.

NS-VC management

− A blocking procedure is used when an NS-VC becomes unavailable for NS user traffic.

− An unblocking procedure is used for the reverse operation. Network congestion indication

− Congestion reporting mechanisms available in the Sub-Network Service implementation shall be used by the Network Service to report congestion.


Functions of BSSGP

The primary function of BSSGP is to provide the radio-

related, QoS, and routeing information that is required to

transmit user data between a BSS and an SGSN.

In the BSS, it acts as an interface between LLC frames and

RLC/MAC blocks.

In the SGSN, it forms an interface between RLC/MAC-derived

information and LLC frames.

A secondary function is to enable two physically distinct

nodes, the SGSN and BSS, to operate node management

control functions.


Functions of LLC

Logical Link Control (LLC): This layer provides a highly reliable ciphered logical link between an MS and its SGSN.

LLC includes functions for the provision of one or more logical link connections discriminated

between by means of a DLCI. sequence control, to maintain the sequential order of frames

across a logical link connection. detection of transmission, format and operational errors on a

logical link connection. recovery from detected transmission, format, and operational

errors. notification of unrecoverable errors. flow control. ciphering.


SCCP

MTP2

MTP3

MTP2

MTP3

SCCP

GsSGSN MSC/VLR

BSSAP+ BSSAP+

L1 L1

SGSN ‑ MSC/VLR signaling plane

Gs interface is the optional interface.

It adopts BSSAP+ protocol to enable combined mobility management and

paging functions so as to improve the effective usage of wireless resources.


Network operation mode (Paging co-ordination)

Paging co-ordination means that the network sends paging messages for

circuit-switched services on the same channel as used for packet-switched

services, i.e., on the GPRS paging channel or on the GPRS traffic channel, and

the MS needs only to monitor that channel.

ModeCircuit Paging

Channel

GPRS Paging

Channel

Paging co-ordination

Network Operation Mode

I

Packet Paging Channel Packet Paging Channel Yes (Gs interface is

present, all MSC-

originated paging of

GPRS-attached MSs shall

go via the SGSN)

CCCH Paging Channel CCCH Paging Channel

Packet Data Channel Not Applicable


II CCCH Paging Channel CCCH Paging Channel No (Gs interface is not

present, all MSC-

originated paging of

GPRS-attached MSs shall

go via the A interface)


III

CCCH Paging Channel Packet Paging Channel

CCCH Paging Channel CCCH Paging Channel


Physical channel

The same as in GSM

The same frequency

The modulation mode

The same TDMA frame definition

The same burst pulse definition

…

The differences between GPRS and GSM

The Multi-frame structure

The channel coding

…

Application

IP/X25

SNDCP

LLC

RLC RLC BSSGP

MAC MACFramerelay

PhysicalLayer

PhysicalLayer

PhysicalLayer

MS BSS

Relay


Packet logic channels

The specific type of PDCH (except PRACH) is determined by RLC/MAC head

and RLC/MAC control message type.

TCH

BCCH

PCH, RACH, AGCH

Packet service channel

PACCH

Packet Data CHannel (PDCH)

Packet control channel

PBCCH

PPCH PRACH PAGCH

PCCCH PDCCH

PDTCH/U PDTCH/D PNCH

PTCCH/U PTCCH/DSACCH


Channel abbreviation

Packet Data Traffic CHannel Uplink - PDTCH/U Packet Data Traffic CHannel Downlink - PDTCH/D Packet Broadcast Control CHannel - PBCCH Packet Common Control CHannel - PCCCH Packet Dedicated Control Channel - PDCCH Packet Paging CHannel - PPCH Packet Random Access CHannel - PRACH Packet Access Grant CHannel - PAGCH Packet Notification CHannel - PNCH Packet Associated Control CHannel - PACCH Packet Timing advance Control CHannel Uplink - PTCCH/U Packet Timing advance Control CHannel Downlink - PTCCH/D


PDTCH (Packet Data Traffic CHannel)

PDTCH transmits the user data in the

mode of packet switching with a transm

ission rate of 0~22.8kbit/s.

All packet data traffic channels are uni-

directional.

Uplink (PDTCH/U) for a mobile originat

ed packet transfer.

Downlink (PDTCH/D) for a mobile term

inated packet transfer.

Packet service channel

PDTCH/U PDTCH/D


PBCCH (Packet Broadcast Control CHannel)

The PBCCH broadcasts parameters used by the MS to access the network for packet transmission operation.

The PBCCH also carries the information transmitted via the BCCH to allow circuit switching operation.

The MS in GPRS attached mode monitors the PBCCH only, if PBCCH is available, otherwise, the BCCH shall be used to broadcast information for packet operation.

The existence of the PBCCH in the cell is indicated on the BCCH via SI13.

Packet control channel

PBCCH


PCCCH (Packet Common Control CHannel) PPCH

Downlink only, used to page MS.

PRACH Uplink only, used to request allocation of one

or several PDTCH/Us or PDTCH/Ds.

PAGCH Downlink only, used to allocate one or severa

l PDTCHs.

PNCH Downlink only, used to notify MS of PTM-M c

all.

If no PCCCH is allocated, the information for packet switching operation is transmitted on the CCCH. If a PCCCH is allocated, it may transmit information for circuit switching operation.

PPCH PRACH PAGCH

PCCCH

PNCH


PDCCH (Packet dedicated control channels)

PACCH

Bi-directional, used to transmit the

packet signaling in data transmission.

PTCCH/U

Used to transmit random access bursts

to allow estimation of the timing

advance for one MS in packet transfer

mode.

PTCCH/D

Used to transmit timing advance

updates for several MS. One PTCCH/D

is paired with several PTCCH/U's.

PACCH

PDCCH

PTCCH/U PTCCH/D


Combinations of packet logic channel

Mode 3: PDTCH+PACCH+PTCCH

Mode 1: PBCCH+PCCCH+PDTCH+PACCH+PTCCH Mode 2: PCCCH+PDTCH+PACCH+PTCCH

In case of small GPRS traffic, GPRS and circuit services use the same BCCH and CCCH in the cell. In this case, only combination mode 3 is needed in the cell.

With the increase of traffic, the packet public channel should be configured in the cell. Channel combination mode 1 and mode 2 should be adopted.

Mode 4: PBCCH+PCCCH

(PCCCH=PPCH+PRACH+PAGCH+PNCH ）


Mapping of packet logic channel

X = Idle frame T = Frame used for PTCCH B0 ~ B11 = Radio blocks

PDCH 52 multi-frame mapping

A radio block is a 4-normal-burst sequence that carries a RLC/MAC PDU (Protocol Da

ta Unit).

The mapping of logical channels onto the radio blocks is defined by means of the

ordered list of blocks (B0, B6, B3, B9, B1, B7, B4, B10, B2, B8, B5, B11).


Multi-frame structure comparison bet. PS and CS

PBCCH+PCCCH (BS_PBCCH_ BLKS=2 、 BS_PAG_BLKS _RES=3 、 BS_PRACH_BLKS=4)

Figure 8b: TDMA fram e m apping for FCCH + SCH + BCCH + CCCH + SDCCH/4(0...3) + SACCH/4(0...3)

IDLE

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Figure 8a: TDMA fram e m apping for FCCH + SCH + BCCH + CCCH FCCH+SCH+BCCH+CCCH

FCCH+SCH+BCCH+CCCH+SDCCH/4+SACCH/4

51 multi-frame mapping of Circuit Switching logic channel

52 multi-frame mapping of Packet Switching logic channel

DL

UL


Packet wireless channel configurations

Reason of adopting static PDCH

To enable that GPRS MS is constantly online in the cell.

To ensure certain QoS of GPRS services.

Reason of adopting dynamic PDCH

GPRS and GSM share wireless resources.

Wireless resources should be adopted in priority; on the other hand,

QoS of voice services should be ensured.

In a cell, the percentage of packet switching services and the

percentage of circuit switching services are constantly changing.

Dynamic PDCH is not visible for voice services.


Packet wireless channel configurations

General principles

The cell should be configured with static PDCH to enable MS to be normally a

ttached on GPRS network as well as certain QoS of GPRS services.

Dynamic PDCH should be configured according to the GPRS traffic forecast,

which should be adjusted as TCH or PDCH usable in the operation process a

ccording to the cell traffic status.

Circuit switching services can seize the channel used by GPRS services.


Allocation of wireless packet resources

Wireless resource allocation and wireless transmission adopt the wireless block (BLOCK) as the b

asic unit.

Each PDCH can be used by several MSs; each MS can use multiple PDCHs at the same time.

B1 B2 B3 B4 B5 B6 B7 B8 B9 B10 B11B0

B1 B2 B3 B4 B5 B6 B7 B8 B9 B10 B11B0

B1 B2 B3 B4 B5 B6 B7 B8 B9 B10 B11B0

MS3MS2

TS 0

TS 1

TS 2

MS1


Transmission principle of data packet on Um interface

Subscriber dataRLC/MAC head LLC head SNDCP head

Subscriber IP packet

LLC FCS

SNDCP PDU

LLC PDU

RLC/MAC block

Normal burst Normal burst Normal burst Normal burst Physical layer


RLC/MAC block structure (GPRS)RLC/MAC data block

An RLC/MAC block containing an RLC data block may be encoded using any of the

available channel coding schemes CS-1, CS-2, CS-3, or CS-4. RLC/MAC blocks

encoded using CS-1 do not contain spare bits.

RLC/MAC block

MAC

header

RLC data block

RLC header RLC data unit Spare

bitsRLC/MAC control block

An RLC/MAC control blocks shall always be encoded using the coding scheme CS-1.

RLC/MAC block

MAC header RLC/MAC control block


RLC/MAC block structure (EGPRS)

RLC/MAC block

RLC/MAC header RLC data block 1 RLC data block 2

(conditional)

RLC/MAC control block

Similar to GPRS

RLC/MAC block

MAC header RLC/MAC control block

RLC/MAC data block

Dissimilar to GPRS


PDCH coding mode

8PSKGMSK

9.05

13.415.6

21.4

8.811.2

14.817.6

22.4

29.6

44.8

54.4

59.2

0.00

10.00

20.00

30.00

40.00

50.00

60.00

CS-1 CS-2 CS-3 CS-4 MCS-1MCS-2MCS-3MCS-4MCS-5MCS-6MCS-7MCS-8MCS-9

Kbps

GPRS

EGPRS


Downlink, 4 TS, MCS-9：

Huawei EDGE test result


Medium access modes

Uplink resource allocation mode

Dynamic allocation : MS determines the blocks on each PDCH.

Fixed allocation : fixed bit mapping is adopted to determine the allocated blocks

in the allocation period.

Extended dynamic allocation : MS determines the blocks on multiple PDCH.

Either the Dynamic Allocation medium access mode or Fixed Allocation

medium access mode shall be supported by all mobile stations and all

networks that support GPRS. The support of Extended Dynamic Allocation is

optional for the network.

Downlink resource allocation mode

Dynamic allocation and fixed allocation.

The difference between the dynamic mode and the fixed mode lies on the dow

nlink measurement time scheduling reserved by MS.


MS multi-TS ability

Concept of MS multi-TS ability

Definition: the multi-TS ability level is 1-29; the bigger the level, the stro

nger the multi-TS ability.

three elements(1 <= Rx + Tx <= Sum):

− Rx ： maximum receiving TS number (downlink TS)

− Tx ： maximum transmission TS number (uplink TS)

− Sum ： maximum total TS number

BSS allocates resources according to the MS multi-TS ability, requeste

d QoS and current resource configuration.


Power control

Power control can improve the spectrum usage and system capacity as w

ell as reduce MS power consumption.

As there is no continuous bi-directional connection in the packet data trans

mission process, GPRS power control is very complicated.

Uplink power control includes open-loop and close-loop power control.

About downlink power control, there is no specific definition in protocol. It li

es on the BTS and its algorithm needs information about downlink, so dow

nlink power control needs MS sends channel quality reports to BTS.


Network control modes

During the network controlled cell re-selection, the network may request measurement reports from the MS and control its cell re-selection. Hence, three types of mode are defined as follows:

NC0: Normal MS controls. The MS shall perform autonomous cell re-selection.

NC1: MS control with measurement reports. The MS shall send measurement reports to the network. The MS shall perform autonomous cell re-selection.

NC2: Network control. The MS shall send measurement reports to the network. The MS shall not perform autonomous cell re-selection.

The network subsystem must support NC0 and should gradually support NC1 and NC2.


CGI

Location Area Identification

MCC MNC LAC CI

Cell Global Identification

MCC (Mobile Country Code): It consists of 3 digits . For example: The MCC of China is "460"

MNC (Mobile Network Code): It consists of 2 digits . For example: The MNC of China Mobile is "00"

LAC (Location Area Code): It is a two bytes BCD code (hex). The value 0000 and FFFF is invalid.

CI (Cell Identity): This code uses two bytes BCD code (hex) to identify the radio cells within a LAI.

For example : 460-00-0011-0001


RAI

Routing area is the sub-set of the location area. In special cases, the two

areas are equal

The division of the routing area is related with traffic distribution and

SGSN processing ability

Location Area Identification

MCC MNC LAC RAC

Routing Area Identification


BSIC

NCC BCC

Base Station Identification Color Code

NCC(PLMN Network Color Code): It comprises 3 bits.

It allows various neighboring PLMNs to be distinguished.

BCC(BTS Color Code): It comprises 3 bits.

It allows distinctions between different radio frequency channels usi

ng the same frequency in neighboring cells.


GMM concept

Routing area: subset of location area Mobility management entities: SGSN, HLR and MS GMM context

MS identification/ MS location information (routing area ID, cell ID)

Current service SGSN address, VLR number (MS only) Encryption algorithm and authentication parameter GMM status

GMM status Idle: GMM context is not established; MS is not reachable. Standby: GMM context is established; MS can receive

paging but cannot implement data transmission. Ready: MS can implement data transmission.


GMM status models

Implicit Detachor

Cancel Location

GPRS Attach

PDU reception

GPRS Detachor

Cancel Location

MM State Model of SGSN

IDLE

READY

STANDBY

READY timer expiryor

Force to STANDBYor

Abnormal RLC condition

PDU transmission

GPRS Attach

READY timer expiryor

Force to STANDBY

GPRS Detach

MM State Model of MS

IDLE

READY

STANDBY


Major functions of GMM

General functions GPRS attachment: MM context is established; MM status is changed to rea

dy. GPRS detachment: MM context is deleted; MM status is changed to idle.

− Originated by MS or network side. Security function: authentication, encryption, identification check, etc. Location management:

− routing area updating

− periodical routing area

− cell updating Specific functions at the network side

GMM context clearing in cooperation with HLR Combined location updating and combined paging in cooperation with

MSC/VLR


Cooperation between GMM and MM

Objectives

To improve the effective usage of wireless resources

To reduce the network signaling traffic

Pre-condition

SGSN and MSC/VLR support Gs interface

Functions

Combined IMSI/GPRS attachment

Combined IMSI/GPRS detachment

Combined routing area/location area updating (including periodical)


Summary

GPRS System Structure

GPRS Network Interfaces & Protocols

GPRS Wireless Subsystem

GPRS Numbering

GPRS Mobility Management (GMM)

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Thank You

21 Gprs Principle Issue2.0

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