(e)gprs workshop introduction functionality

8/6/2019 (E)GPRS Workshop Introduction Functionality

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1 © Nokia Siemens Networks

EGPRS Workshop(Agenda: Basics,planning & optimization,RG-10 feature descriptions)




TIME DAY-1 (15- March) DAY-2(16- March) DAY-3(17- March) DAY-4(18- March)

9.30-11.00Introduction toGPRS/EGRS

Network AuditIntroduction toGPRS/EGRS

Network Audit,Capacity Audit

11.15 - 12.45 Configuration/ ParameterAssessments

Capacity AuditConfiguration/

ParameterAssessments

Optimization

12.45 - 13.30 LUNCH LUNCHLUNCH LUNCH

13.30 – 14.30Configuration/


OptimizationConfiguration/


Optimizationwith TrailResults

14.30 – 15.30Planning and

Network Audit OptimizationPlanning and

Network Audit

Optimizationwith Trail

Results

Workshop – Time Schedule

Beginners Intermediate




Objectives

At the end of the course participants will be able to

• Understand the Architecture, Protocols, Interfaces of the DATA Network End toEnd.

• Understand the Process of DATA Planning & Optimization.

• Perform Network Assessment End to End.

• Use BSS counters and KPIs in Daily Work

• Perform Basic Optimization Tasks

• Know which features can be used in Optimization Process




Content

• Introduction

– GMSK and 8PSK modulation – EGPRS Link Adaptation and incremental Redundancy (IR)

– State, mobility, session and radio resource management

• Dimensioning and planning

– Network Analysis and planning inputs

–Deployment planning

– Air Interface capacity planning (CDEF, CDED)

– Connectivity capacity planning (BTS, EDAP, PCU, Gb, SGSN)

• Optimization

– Configuration and feature assessment

–

BSS (KPI) and E2E performance assessment – Signaling capacity & resource allocation improvement

– Data rate optimization Connectivity capacity (BTS, EDAP, PCU, Gb, SGSN)

RTSL data rate improvement and Multislot usage maximization (BSS)

– Mobility improvement




• Network Architecture & Interfaces - Modulation and Link Adaptation

• Protocols & Layers

•

Air –

Interface, RLC Mappings

• (E)GPRS Resource Allocation

• Territory Method

• Cell selection and re-selection

• Air interface - Modulation and Link Adaptation

• GPRS Coding Schemes (CS)

• EGPRS Modulation and Coding Schemes (MCS)

• GMSK and 8PSK

• EGPRS Link Adaptation and incremental Redundancy (IR)



6 © Nokia Siemens Networks Presentation / Author / Date

(E)GPRS Optimization –Network Element and Configuration Assessment

BSC

GGSN

IP/MPLS/IPoATM -

Applicatio

n Servers

(co -

located

2G

SGSNBTS

HLR/

AC/ EIR

TCSM

TC

MSC/VLR

Abis Gb

BSC

BSC

GGSNGGSN

-backbone

Application

Servers

2G

SGSN

2G

SGSNBTS

HLR/

AC/ EIR

HLR/

AC/ EIR

TCSM

TC

MSC/VLR

GnGi

Gs

RF interface

• Coverage

•C/I

• Capacity

• Traffic volume

• Mobility

MS/Client

parameters

•

GPRS/EDGEcapability andrelease

•Multislot support

Abis interface

• EDAP size /

dimensioning

• # of E1/T1s

• GPRS/EDGE

traffic

Gb interface

• Bearer size

• IP v.s. FR

• Dimensioning

BTS

• GPRS territory

• BTS HWconsiderations

(TRX & BB-card)

• BTS SW (EPCR)

BSS

• PCU variant &

dimensioning

• PCU strategy in

mixed

configuration

• BSS SW and

features

SGSN

• Unit capacity

(PAPU etc.)

• BSS Gb Flow

control

RF

Server

• load

• settings (Linux/Win)

HLR

• QoS profile

• GPRS settings


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V2

(E) GPRS Functionality


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Functionality - Content

Introduction

• Network Architecture and Interfaces• Mobile Classes• Network Protocols

• Multiframe and Header Structure• Air Interface Mapping – Physical and Logical Channel

Procedures• State and Mobility Management

• GPRS Attach/Detach• Routing Area

•

Session Management (PDP context)• Temporary Block Flow

•RLC/MAC Header•TBF Establishment



Module objectives

After completing this module, the participant should be able to:

• Explain the (E)GPRS main procedures: Mobilitymanagement, PDP context, Temporary Block Flow

• Describe the air interface principles: 8PSK modulation,Channel Modulation and Coding Schemes, Link Adaptation,Resource Allocation, Cell Selection/Re-selection processes

• List the principles of EDAP interface

• Explain the PCU main functionality

• Describe the Gb interface main structure



BSC

BTS

•Class C Packet only

(or manually switched between GPRS and speech modes)

• Class B Packet and Speech (not at same time)

(Automatically switches between GPRS and speech modes)

• Class A Packet and Speech at the same time(DTM is subset of class A)

(E)GPRS Mobile Terminal Classes

http://www.nokia.fi/puhelimet/puhelinmallit/cardphone20/

http://www.nokia.fi/puhelimet/puhelinmallit/n92/



http://www.nokia.fi/puhelimet/puhelinmallit/6230i/


http://www.nokia.fi/puhelimet/puhelinmallit/cardphone20/



(E)GPRS Multislot Classes

Type 1

Multislot Classes 1-12- Max 4 DL or 4 UL TSL (not at same time)- Up to 5 TSL shared between UL and DL- Minimum 1 TSL for F Change- 2-4 TSL F Change used when idle

measurements required

Multislot Classes 19-29- Max 8 downlink or 8 uplink

(not required at same time)- 0-3 TSL F Change

Multislot Classes 30-45 (Rel-5)- Max 5 downlink or 5 uplink (6 shared)- Max 6 downlink or 6 uplink (7 shared)

Type 2

Multislot Classes 13-18- simultaneous receive & transmit- max 8 downlink and 8 uplink(Not available yet, difficult RF design)

DL

UL

DL

UL

1 TSL for F Change

1 TSL for Measurement

DL

UL




MSCHLR/AuCEIR

BSCBTS

Um

PSTNNetwork

GSM & (E)GPRS Network Architecture

PCU

EDAPGb

GatewayGPRSSupportNode(GGSN)

ChargingGateway (CG)

LocalAreaNetwork

Serve

rRouter

Corporate 1

Server

Router

Corporate 2

Datanetwork(Internet)

Datanetwork

(Internet)

Billing System

Inter-PLMNnetwork

GPRSINFRASTRUCTURE

BorderGateway(BG)

LawfulInterceptionGateway (LIG)

GPRSbackbonenetwork(IPbased)

ServingGPRSSupportNode(SGSN)

SS7Network

PAPU

DomainNameServer(DNS)




(E)GPRS Network Elements and Primary Functions

SGSN

• Mobility Management

• Session Management

• MS Authentication

• Ciphering

• Interaction with

VLR/HLR

• Charging and statistics• GTP tunnelling to

other GSNs

GGSN• GTP tunnelling to

other GSNs• Secure interfacesto externalnetworks

• Charging &statistics

• IP addressmanagement

Charging Gateway• CDR consolidation• Forwarding CDR

information tobilling center

Border Gateway• Interconnects different

GPRS operators'backbones

• Enables GPRS

roaming

• Standard Nokia IProuter family

Domain Name Server• Translates IP host names to IP

addresses• Makes IP network configuration

easier• In GPRS backbone SGSN uses

DNS to get GGSN and SGSN IPaddresses

•

Two DNS servers in the backboneto provide redundancy

Legal Interception Gateway• Enables authorities to intercept

subscriber data and signaling• Chasing criminal activity• Operator personnel has very

limited access to LI functionality• LI is required when launching the

GPRS service




GSM and (E)GPRS Interfaces

Gf

D

Gi

C

E

Gp

Gs

Signaling and Data Transfer InterfaceSignaling Interface

MSC/VLRTE BSS

TEPDN

R Um

Gr

HLR

Other PLMN

GGSN

Gd

SM-SCSMS-GMSC

SMS-IWMSC

EIR

GnLAN SW

/ IP BB

DNS CG LIG

Gn Gn

Gc

A

Gb

MT

SGSN SGSN GGSN

Gn

Gn Gn

Optional




EGPRS Implementation

• Can be introduced incrementally to the network where the demand is

• EGPRS capable MS

• Network HW readiness/upgrade (BTS and TRX)

• TRS capacity upgrade (Abis and Gb!)

• Dynamic Abis

GMSK coverage

8-PSK coverage

AA-bis

Gb

Gn

BTS

BTS

BSC

SGSNGGSN

MSC

More capacity ininterfacesto support higher datausage

EDGE capableTRX,GSMcompatible

EDGEcapableterminal,

GSMcompatible

EDGEfunctionality in

the networkelements





(E)GPRS Protocol Architecture

These following figures shows the

different protocols between thedifferent network elements of a(E)GPRS networks. As it can beseen, the BSS network relatedprotocols are the physical (L1/RF)and RLC/MAC layers. The

RLC/MAC, LLC and SNDCP layersare (E)GPRS specific layers, but thehigher layers are applicationdependent.

Appln. layer

EGPRS Spec layer

Data Blocks segmentation betweenprotocols




SNDCP (Subnetwork Dependent ConvergenceProtocol) Layer

• Multiplexer/demultiplexer for different networklayer entities onto LLC layer

• Compression of protocol control information(e.g. TCP/IP header)

• Compression of data content (if used)

• Segmentation/de-segmentation of data to/fromLLC layerLLC

SNDCP

IP

TCP/UDP

APP

RLC

MAC

GSM RF




Logical Link Control (LLC) Layer

LLC

SNDCP

IP

TCP/UDP

APP

RLC

MAC

GSM RF

•

Reliable logical connection between SGSN and•Independent of underlying radio interface protoc

ControlAddress

FCSInformation

LLC Frame

1 1-3 1-1520 3 Octets




LLC Reliability – HLR QoS Profile

• In practice only reliability classes 2

and 3 work today properly from theend user satisfaction perspective andcan thus be commercially used.

• There are some terminals in themarket that can not support the usageof reliability class 2.

Resulting R99 Attribute Derived from R97/98Attribute

Name Value

Value Name

SDU error ratio

10-6 1, 2

Reliability class10-4 3

10-3 4, 5

Residual bit error ratio

10-5 1, 2, 3, 4

Reliability class4*10-

3 5

Delivery of erroneousSDUs

'no' 1, 2, 3, 4

Reliability class'yes' 5

SDU error ratio:<= 5*10-4 RLC ack> 5*10-4 RLC unack

Radio Link Control (RLC)/ Medium Access Control




Radio Link Control (RLC)/ Medium Access Control(MAC) Layers

RLC• Achieves reliable transmission of data across air interface

• Segmentation/de-segmentation of data from/to LLC layer

MAC•

Control of MS access to common air-interface medium• Flagging of PDTCH/PACCH occupancy

LLC

SNDCP

IP

TCP/UDP

APP

RLC

MAC

GSM RF




Downlink RLC Data Block with MAC Header

USF - Uplink State Flag

TFI - Temporary FlowIndicator

BSN - BlockSequence Number

FBI - Final Block Indicat

Uplink RLC Data Block with MAC Header




Uplink RLC Data Block with MAC Header

TFI - Temporary Flow

Indicator = TBF ID.

BSN - BlockSequence Number=RLC block ID within

TBF

TLLI - TemporaryLogical LinkIdentifier = type ofmobile ID

Countdown value -used to calculatenumber of RLCblocks remaining

GSM RF Layer




GSM RF Layer

• Modulation/demodulation

• Bit inter-leaving

• TDMA frame formatting

• Cell selection/re-selection

• Tx power control

• Discontinuous reception (DRx)

LLC

SNDCP

IP

TCP/UDP

APP

RLC

MAC

GSM RF




(E)GPRS Protocol Architecture – Mapping to RFlayer

• LLC frames aresegmented into

RLC Data Blocks

• In the RLC/MAClayer, a selectiveARQ protocolprovidesretransmission oferroneous RLCData Blocks

• When a complete

LLC frame issuccessfullytransferred acrossthe RLC layer, it isforwarded to theLLC layer.




Bursts on the Air Interface – Mapping RLC blocks

1 TDMA frame = 4.615 ms= BURST PERIOD

RLC/MAC Blocks

TDMA Bursts

RLC Blocks

4 x TDMA Frames = 4 Bursts = 1 Radio block = 18.46 ms = 1-2 RLC block(s)

Note: Amount of RLCblocks per radio blockdepends on used

(modulation) codingscheme (M)CS

0 70 70 70 7

12 x RLC/MAC Blocks = 1 x 52 PDCH MultiFrame = 240 ms

12 RLC/MAC Blocks / 0.240 s = 50 RLC/MAC Blocks / s

0 1 2 3 4 5 6 7 8 9 10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

51

B0(0..3) B1(4..7) B2 (8..11)PTCCH

B3(13..16) B4(17..20) B5(21..24)IDLE

B6(26..29) B7(30..33) B8(34..37)PTCCH

B9(39..42) B10(43..46) B11(47..50)IDLE

52 TDMA Frames (240 ms)

GSM and (E)GPRS Multiframe




GSM and (E)GPRS Multiframe

TS 6FCCH

GSM Signalling GSM Traffic GPRS traffic

TDMA frameTS 0 TS 1 TS 2 TS 3 TS 4 TS 5 TS 7

SCH Radio Block 0

Radio block 1

FCCHRadio Block 2

SCH

Radio Block 3

Radio Block 4

FCCHSCH

Radio Block 5

Radio Block 6

FCCHSCH Radio Block 7

Radio Block 8

FCCHSCH

Radio Block 9

Radio Block 10

Radio Block 11

IDLE

PCH+AGCH

PCH+AGCH

BCCH

PCH+AGCH

PCH+

AGCH

PCH+AGCH

PTCCH

PTCCH

IDLE

IDLE

0123456789

10111213141516171819202122232425262728293031323334

3536373839404142434445464748495051

SACCH

IDLE

TCH

TCH

TCH

TCH

TCH

TCH




(E)GPRS Logical Channels

GPRS Air Interface Logical Channels

CCCH

Common Control Channels

DCH

Dedicated Channels

PCH

Paging CH

AGCH

Access Grant CH

RACH

Random Access CH

Existing GSM Signaling Channels(Shared with GPRS Signaling)

PACCHPacket Associated

Control CH

PDTCH

Packet Data TCH

NEW GPRS Signaling and Data

Channels




Functionality - Content

Introduction

•

Network architecture and Interfaces• Mobile classes• Network Protocols

• Multiframe and header structure• Air interface mapping – physical and logical channel

Procedures• State and Mobility Management

• GPRS Attach/Detach• Routing Area

• Session Management (PDP context)• Temporary Block Flow

•RLC/MAC Header•TBF Establishment




(E)GPRS Procedures - Content

• Mobility Management and State Management

• Mobile States

• GPRS attach

• GPRS detach

•

Routing Area• Session Management

• PDP context activation

• Temporary Block Flow

• RLC/MAC Header• TBF establishment




GPRS Mobility Management - Mobile States

MS location not known,subscriber is notreachable by the GPRSnw.

IDLE

READY

STANDBY

READYTimerexpiry

MOBILEREACHABLETimer expiry

PacketTX/RX

GPRS

Attach/Detach

MS location known toRouting Area level.MS is capable to beingpaged for point-to-point data.

MS location known tocell level. MS istransmitting or has justbeen transmitting. MS iscapable of receivingpoint-to-point data.




GPRS Mobility Management - Mobile States

• GPRS MM is based on States State Transition occurs when a pre-defined

transaction takes place GPRS Attach (/Detach)• MS makes itself known to the network

• The authentication is checked and the mobile location is updated

• Subscriber Information is downloaded from the HLR to the SGSN

• State transition Idle to Ready

• Normal procedure should occur within 5 seconds each• Mobility Management before Session Management:

• GPRS attach needs to happen before PDP context activation

• States controlled by timers

•

READY Timer• MOBILE REACHABLE Timer

• Timer values are configurable with SGSN Parameter Handling




Attach Procedure

• The GPRS Attach procedure establishes a GMM context. This procedure

is used for the following two purposes:• a normal GPRS Attach, performed by the MS to attach the IMSI for GPRS

services only

• a combined GPRS Attach, performed by the MS to attach the IMSI forGPRS and non-GPRS services

• Attach procedure description

• MS initiates by sending Attach Request

• If network accepts Attach Request it sends Attach Accept

– P-TMSI, RAI

• If network does not accept Attach request it sends Attach Rejected

• MS responds for Attach Accept message with Attach Complete (only if P-TMSI changes)




(E)GPRS Attach Process – Combined GPRS/IMSIAttach

1. Attach Request

2. Identification Request

2. Identification Response

3. Identity Request

3. Identity Response

4. Authentication

5. (IMEI Check - optional)

6a. Update Location

6b. Cancel Location

6c. Cancel Location Ack

6d. Insert Subscriber Data

6e. Insert Subscriber Data Ack

MS BSS new SGSN old SGSN GGSN HLREIRoldMSC/VLR

newMSC/VLR

(E)GPRS A h P C bi d GPRS IMSI




(E)GPRS Attach Process – Combined GPRS/IMSIAttach

6f. Update Location Ack

7a. Location Update Request

7b. Update Location

7c. Cancel Location

7d. Cancel Loc. Ack

7e. Insert Subscriber Data

7f. Insert Subscriber Data Ack

7g. Update Location Ack7h. Location Update Accept

9. Attach Complete

8. Attach Accept

10. TMSI Reallocation Complete

MS BSS new SGSN old SGSN GGSN HLREIRoldMSC/VLR

newMSC/VLR

D h P




Detach Process

• GPRS Detach procedure is used for the following two

purposes:• a normal GPRS Detach

• a combined GPRS Detach (GPRS/IMSI detach, MSoriginated)

• MS is detached either explicitly or implicitly:

• Explicit detach: The network or the MS explicitly requestsdetach.

• Implicit detach: The network detaches the MS, without

notifying the MS, a configuration-dependent time after themobile reachable timer expired, or after an irrecoverable radioerror causes disconnection of the logical link

(E)GPRS D h P




(E)GPRS Detach Process

2. Delete PDP Context Request1. Detach Request

2. Delete PDP Context Response

3. IMSI Detach Indication

5. Detach Accept

MS BSS GGSNSGSN MSC/VLR

4. GPRS Detach Indication

Session Management - Establishing a PDP




• PDP Context (Packet Data Protocol): Network level

information which is used to bind a mobile station (MS) tovarious PDP addresses and to unbind the mobile stationfrom these addresses after use

• PDP Context Activation• Gets an IP address from the network

•Initiated by the MS

• Contains QoS and routing information enabling data transfer between MS andGGSN

• PDP Context Activation and Deactivation should occur within 2 seconds

Session Management Establishing a PDPContext

PDP C t t A ti ti 1




MSC

PSTNNetwork

GPRSINFRASTRUCT

URE

HLR/AuCEIR



GPRSbackbonenetwork

(IPbased)

PDP Context Activation - 11. MS sends "Activate PDP Context Request" toSGSN

2. SGSN checks against HLR


Datanetwork

(Internet)

Access

Point

SS7Network

APN="Intranet.Ltd.com"

2.ServingGPRSSupportNode(SGSN)

Access Point Name = Reference to an external packet data network the user wants to connect to

BSCBTS

U

m

1.

PDP C t t A ti ti 2




MSC

PSTNNetwork

GPRSINFRASTRUCT

URE

HLR/AuCEIR

PDP Context Activation - 2Finding the GGSN

3. SGSN gets the GGSN IP address from DNS4. SGSN sends "Create PDP Context Request" to

GGSN


Datanetwork

(Internet)

SS7Network

4.


GPRSbackbonenetwork

(IPbased)

3.DomainNameServer(DNS)


Access

Point

BSCBTS

U

m

DNS (Domain Name System) = mechanism to map logical names to IP addresses

PDP C t t A ti ti 3




MSC

GPRSINFRASTRUCT

URE

HLR/AuCEIR

PSTNNetwork

PDP Context Activation - 3Access Point Selection

Access Point Name refers to theexternal network the subscriber wantsto use


SS7Network


GPRSbackbonenetwork

(IPbased)



Access

Point APN="Intranet.Ltd.com"

Datanetwork

(Internet)

BSCBTS

U

m

PDP C t t A ti ti 4




MSC

PSTNNetwork

GPRSINFRASTRUCT

URE

HLR/AuCEIR


Datanetwork

(Internet)

Access

Point APN="Intranet.Ltd.com"


SS7Network

5.


GPRSbackbonenetwork

(IPbased)

6.


BSCBTS

U

m

User (dynamic) IP address allocated5. GGSN sends "Create PDP Context Response" back

to SGSN6. SGSN sends “Activate PDP Context Accept“ to the

MS

PDP Context Activation - 4Context Activated

Temporary Block Flow





Temporary Block Flow (TBF):

• Physical connection where multiple mobile stations can share one or more traffic channels –

each MS has own TFI• The traffic channel is dedicated to one mobile station at a time (one mobile station is

transmitting or receiving at a time)• Is a one-way session for packet data transfer between MS and BSC (PCU)• Uses either uplink or downlink but not both (except for associated signaling)• Can use one or more TSLs

Comparison with circuit-switched:• normally one connection uses both the uplink and the downlink timeslot(s) for traffic

In two-way data transfer:• uplink and downlink data are sent in separate TBFs - as below

BSC

Uplink TBF (+ PACCH for downlink TBF)

Downlink TBF (+ PACCH for uplink TBF)

PACCH (Packet Associated Control Channel): Similar to GSM CSW SACCH

TLLI / TBF Concept




TLLI / TBF Concept

TBF (TFI + TSL)

MS SGSN GGSN

Internet orIntranet

GPRS CORE

BSS

TBF (RLC / MAC Flow)

TBF (LLC Flow)

PCUBTS

TLLI (GTP Flow)

P-TMSI

HLRVLR

IMSI

TMSI


http://www.nokia.fi/puhelimet/puhelinmallit/8800/

http://www.nokia.fi/puhelimet/puhelinmallit/8800/





• DL TBF

• Network starts and releases TBFs

• FBI (Final Block Indicator) indicates the last block in a DL TBF

• UL TBF

• Close-ended: limited number of octets

• Open-ended: an arbitrary number of octets

• MS may request either close-ended or open-ended TBF

– NW decides the type in PACKET UPLINK ASSIGNMENT

•

MS can ask network to give more resources if needed

E t bli hi DL TBF d S di D t




Establishing a DL TBF and Sending Data

Paging

UL TBF forMS location

Packet Control Ack (for TA)

Packet Polling

Packet Downlink Assignment

Data / Signalling

Ack / Nack

Packet Channel Request

Packet Paging Response (LLC Frame)

BTS

RACH

AGCH

PDTCH

PACCH

PACCH

PACCH

PCH

Immediate Assignment for UL TBF

Immediate Assignment for DL TBF

AGCH

PDTCH

PACCH

PACCH

Multiple Mobiles and Downlink Transmission




Multiple Mobiles and Downlink Transmission

TFI2

TFI5

TFI3

TFI2 BTS

The TFI included in the Downlink RLC Blockheader indicates which Mobile will open the RLCBlock associated with its TBF

RLC Data Block

Establishing an UL TBF and Sending Data




Establishing an UL TBF and Sending Data

Packet Channel Request

Immediate Assignment for UL TBF

UL Data

Signaling + Ack/Nack

Final UL Data

Final Ack/Nack

Packet control Ack

RACH

AGCH

PDTCH

PACCH

PDTCH

PACCH

PACCH

BTS

Multiple Mobiles and Uplink Transmission




• Several mobiles can share one timeslot

• Maximum of 7 Mobiles are queued in the Uplink

• Mobile transmissions controlled by USF (Uplink State Flag) sent on DL(dynamic allocation)

TS 1

TS 2

TS 3

Uplink State Flag

• Mobile with correct USF will transmit in following Uplink block

• Timeslot selected to give maximum throughput

New MS







USF =1

USF =2

USF =3

USF = 3 BTS

RLC Data Block

The USF included in the Downlink RLC Block header

identifies which Mobile will transmit in the following UplinkRLC Block

Routing Area




Routing Area

The Routing Area Update procedure is used for the followings:

• a normal Routing Area Update• a combined Routing Area Update

• a periodic Routing Area Update

• an IMSI Attach for non-GPRS services when the MS is IMSI-

attached for GPRS services.

• Routing Area (RA)

• Subset of one, and only one Location Area (LA)

• RA is served by only one SGSN

• For simplicity, the LA and RA can be the same

• Too big LA/RA increases the paging traffic, while too smallLA/RA increases the signaling for LA/RA Update

Routing Area



Routing Area

LocationArea (LA)

RoutingArea (RA)

SGSN

MSC/VLR

GS Interface

• Bad LA/RA border design can significantly increase the

TRXSIG on LA/RA border cells causing the cell-reselectionoutage to be longer

• LA/RA border should be moved from those areas where thenormal CSW and PSW traffic is very high

(e)gprs workshop introduction functionality

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