GPRS Scenarios - pudn.comread.pudn.com/.../ebook/733566/GPRS/cd-rom-training_GPRS_scenari… · GPRS Scenarios 1MAT 08.10.02 ... Location Update procedures Lots of LA-procedures initiated

2 MAR | Re |08/00 |

1 GPRS General Packet Radio ServicesGPRS Scenarios

1MAT 08.10.02

GPRSGeneral Packet Radio Services

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GPRS scenarios

GPRS General Packet Radio ServicesGPRS Scenarios

1MAT | 08.10.02 |

Routingarea

GPRS state model

GPRS mobilitymanagement

GPRS sessionmanagement

GPRS networkoperation modes

2

Your Lecturer is:

Reiner StuhlfauthRohde&Schwarz

Training Center, Munich


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Structure of presentation

�GPRS - Routing area

�GPRS - State models inside MS

�GPRS - Mobility management

�GPRS - Session management

�GPRS - Network operation modes

Outline of Presentation


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GPRS-Routing AreaSignalling quantity needed

high

low

Size of Location Areasmall big

Signalling in Uplink direction, mainlyLocation Update procedures

Lots of LA-proceduresinitiated by MS

Only a few LA-proceduresinitiated by MS


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GPRS-Routing AreaSignalling needed

high

low


Signalling in Downlink direction,i.e. Paging calls sent over allradio cells belonging to that location area

Paging over a largelocation area

Paging over smalllocation area


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Signalling neededhigh

low


Signalling in Uplink direction

GPRS-Routing Area

Signalling in Downlink direction

Envelope curve of uplink and downlink signalling.The minimum ofsignalling obtained is the desired size

of the location area

Circuit switched


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Signalling neededhigh

low


Signalling in Uplink directionSignalling in Downlink direction

NEW envelope curve of uplink and downlink signalling.The new minimum of

signalling obtained is the desired sizeof the routing area

Circuit switched

GPRS-Routing Area

Packet switched

Size of Routing Area

Packet switchedrequires morepaging in DL


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Location Area IdentificationMCC MNC LAC

LAI, Location Area Identity

= RACRAI LAI + = LACMNCMCC + + + RAC

RAI, Routing Area Identity

GPRS-Routing Area

MCC = Mobile Country Code MNC = Mobile Network CodeRAC = Routing Area Code LAC = Location Area Code


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GPRS Routing area update procedures

Location Updates in GPRS

• Routing Area Update, RAC changes

• Cell Identity Update if requested

• Periodic Routing Area Update, Timer T3312 expires


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GPRS Routing area update procedures

MS Network

ROUTING AREA UPDATE REQUEST

If P-TMSI orTMSI allocated,or Receive N-PDUNumber needed

ROUTING AREA UPDATE ACCEPT

ROUTING AREA UPDATE COMPLETE

Stop T3330

Start T3330

Stop T3350

Start T3350

or

ROUTING AREA UPDATE REJECTStop T3330

ROUTING AREA UPDATE REQUESTStart T3330

If P-TMSI orTMSI allocated,or Receive N-PDUNumber needed

Routing area update procedure


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GPRS Routing area update proceduresCell update procedure

• If MS initiated cell re-selection in READY state, cellupdate informs the SGSN about the new serving cell•Cell update is done by transmitting an LLC frame•Parameter NCO, Network Control Order in SysInfo:MS or network initiated cell reselection

The network may request measurement reports from the MS and control its cellre- selection.

This is indicated by the parameter NETWORK_CONTROL_ORDER.

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

NC1 MS control with measurement reports The MS shall send measurement reports.

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


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GSM-state model of MS

Initialisation

Initial Cell Selection

GSM IDLE Mode

GSM DEDICATED Mode

IMSI attach

Call setupCall release

IMSI detach

•Power on•SIM card check•Register and timer reset

•Initial cell selection•Network selection•Reading SysÍnfo on BCCH

•Cell re-selection•Network re-selection•Listening to paging channels•MS originated call procedures•Perform location update

•Rx/Tx active•Send measurement report•Obey handover command


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GPRS-state model of MS

GPRS IDLE State

GPRS STANDBY State

GPRS READY State

GPRS attach GPRS detach

READY Timer T3314 expiry

PDU transmission

Initialisation and cell selection


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GPRS-state model of MSGPRS IDLE State

•MS is not ready for GPRS Services

•MS may be switched off

•MS of class A or class B may be IMSI attached

•MS reads SysInfo to know whether GPRS is supported

•If packet data transfer is requested by higher layers,the MS is initiating the GPRS attach procedure


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GPRS-state model of MSGPRS STANDBY State

•MS is GPRS attached

•MS performs routing area update if necessary

•GMM context is established

•PDP context may be activated or deactivated

•MS listens to paging channels

•If higher layers request data transfer, MS starts PDPcontext activation if necessary and TBF establishment


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GPRS-state model of MSGPRS READY State

•MS is GPRS attached and PDP context is active

•MS performs cell update if necessary

•MS must be in READY state to transfer data

GPRS READY State

Packet Idle mode

Packet Transfer mode

Mobility management Radio Resource management


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GPRS Mobility Management

PDU transmission

GPRS Attach

READY timer expiryorForce to STANDBY

GPRS Detach GPRS Attach

PDU reception

GPRS Detachor

Cancel Location

MM State Model of MS MM State Model of SGSN

IDLE

STANDBY

READY

IDLE

STANDBY

READY

READY timer expiryorForce to STANDBYorAbnormal RLC condition

Mobility Management States


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FieldIMSIMM StateP-TMSIP-TMSI SignatureIMEIMSISDNRouteing AreaCell IdentityCell Identity AgeVLR NumberNew SGSN Address

Authentication TripletsKcCKSNCiphering algorithmRadio Access ClassmarkSGSN ClassmarkDRX ParametersMNRGNGAFPPFSMS ParametersRecoveryRadio Priority SMS

FieldIMSINSAPIMSISDNPDP TypePDP AddressDynamic AddressAPN in UseQoS Profile NegotiatedSGSN AddressMNRGRecoverySNDSNUCharging IdReordering Required

Field SIMIMSI XMM StateP-TMSI XP-TMSI Signature XRouteing Area XCell IdentityKc XCKSN XCiphering algorithmClassmarkDRX ParametersRadio Priority SMS

SGSNMS GGSN

GMM context in 3 network elements: MS, SGSN and GGSN


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MS Network

ATTACH REQUESTStart T3310

ATTACH ACCEPT

ATTACH REJECTStop T3310

Stop T3310

or

ATTACH COMPLETEStop T3350

ATTACH REQUESTStart T3310

If P-TMSI and/orTMSI allocatedStart T3350

If P-TMSI and/orTMSI allocated

GPRS Attach procedure


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GPRS Mobility ManagementGPRS Attach procedure

•GPRS Attach is mandatory

•Combined GPRS/IMSI attach is possible

•Establishes a GMM context

•Negociated parameters:

P-TMSI, TMSI, DRX parameters, READY timer value, Routing Area Identity

Periodic routing area update timer valueMS radio access capabilities, e.g. multislot class

ciphering keys, MS power class, etc.


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MS Network

DETACH REQUESTStart T3321

DETACH ACCEPTStop T3321

or at MS power switch off

DETACH REQUEST

MS initiated detach procedure

GPRS Detach procedure


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GPRS Mobility ManagementGPRS Detach procedure

•GPRS detach may be initiated by MS or network

•GPRS detach will delete GMM context

•There are different causes for GPRS detach:

”GPRS detach with switching off”, ”GPRS detach without switching off”,

”IMSI detach”, ”GPRS/IMSI detach with switching off”,

“re-attach not required”“re-attach required”

“IMSI detach after VLR failure”


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SIM card shall handle 2result parameter sets1 for GSM1 for GPRS=> problemswith old SIMcards. MS willstore the values instead.


RAND

Triplet forIMSI "xyz" ?

RAND SRES KcSR

ES

SIM

A3

Ki RAND

SRES

AUC

A3

Ki RAND

SRES

MSC

SRES =SRES ?

GPRS authentication procedure

GPRS uses the samealgorithm for authenticationthat is known from GSM


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GPRS Mobility ManagementGPRS ciphering procedure

The ciphering key Kc iscalculated likeknown from GSM.

SIM card shall handle 2result parameter sets1 for GSM1 for GPRS=> problemswith old SIMcards. MS willstore the values instead.

RAND

Triplet forIMSI xyz ?

SIM AUC

MSC

Ki RAND

A8

Kc

Ki RAND

A8

Kc

Kc

RANDSRES

Kcstore


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INPUT DIRECTION

Kc CIPHERALGORITHM

Kc CIPHERALGORITHM

PLAIN TEXT PLAIN TEXTCIPHERED TEXT CIPHERED TEXT

SGSN/MS MS/SGSN

OUTPUT OUTPUT

INPUT DIRECTION

GPRS ciphering procedure

Kc 64 bits, derived from Kc generation procedure

INPUT 32 bits, LLC frame dependent parameter, set to random initial value

DIRECTION 1 bit, indicates the direction

OUTPUT 1600 octets max.

CIPHER ALGORITHM used ciphering algorithm, A5/x, ordered by network


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GPRS: Session Management

PDP-Address

PDP-Address

GPRS-Network

Application A:Internet

Application B:E-Mail

Identifies PacketData Protocol ofapplication

Packet Data Protocol - Address, PDP-address


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GPRS-Session Management

GGSN associated with:X.121 address

TLLI

X.121 address SAP

IP address SAP

NSAPI-1

NSAPI-2

Gi

GGSN associated with:IP address

Gi

GPRS MS

SGSNIdentifiesApplication onMS-Side

IdentifiesLogical Link between SGSN and MS

External PDN X.121

External PDN IP

Use of TLLI and NSAPI to transmit Data

Use of TLLI and NSAPI

NSAPI: Network Service Access Point IdentifierTLLI: Temporary Logical Link Identifier


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Deactivate PDP Contextor

MM state change to IDLEActivate PDPContext

INACTIVE

ACTIVE

Packet Data Protocol State


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MS SGSN GGSN

2. SecurityFunctions

1. Activate PDPContext Request

3. Create PDPContext Request

4. Create PDPContext Response

5. Activate PDPContext Accept

- NSAPI- PDP Address- PDP Type- QoS requested

- Access Point Name - PDP Configuration Options

- determines PDP Address (if dynamic)- determines external PDN

- handles PDP Configuration Options- may restrict QoS

- add NSAPI, PDP Address, and GGSN Address into

PDP Context- determines

Radio Priority Level

- TID- PDP Address- NSAPI

- QoS negotiated- Radio Priority Level- PDP Configuration

Options

PDP Context Activation Procedure


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MS SGSN GGSN

3. PDU Notification Request

HLR

1. PDP PDU

2. Send Routing Info for GPRS

2. Send Routing Info for GPRS Ack

4. Request PDP Context Activation

5. PDP Context Activation procedure

3. PDU Notification Response

Network oriented PDP-Context Activation Procedure


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PDP-Context Modification

4. Modify PDP Context Accept

2. Update PDP Context Response

1. Update PDP Context Request

3. Modify PDP Context Request

SGSN GGSNMS


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PDP-Context Deactivation Procedure

GGSN

4. Deactivate PDP Context Accept

3. Delete PDP Context Response

3. Delete PDP Context Request

1. Deactivate PDP Context Request

SGSNMS

2. Security Functions


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GPRS: Session ManagementPDP context in 3 network elements: MS, SGSN and GGSN

FieldPDP Context IdentifierPDP StatePDP TypePDP AddressAPN SubscribedAPN in UseNSAPITIGGSN Address in UseVPLMN Address Allowed

QoS Profile SubscribedQoS Profile RequestedQoS Profile NegotiatedRadio PrioritySend N-PDU NumberReceive N-PDU NumberSNDSNUCharging IdReordering Required

FieldIMSINSAPIMSISDNPDP TypePDP AddressDynamic AddressAPN in UseQoS Profile NegotiatedSGSN AddressMNRGRecoverySNDSNUCharging IdReordering Required

GGSNMS SGSN

FieldPDP TypePDP AddressPDP StateDynamic Address AllowedAPN RequestedNSAPITIQoS Profile RequestedQoS Profile NegotiatedRadio PrioritySend N-PDU NumberReceive N-PDU Number


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GPRS network operation modes

CCUBSC PCU

HLR

GMSCMSC

SGSN GGSN

PSTN

ISDN

PDN

CCU

CCU

CCU

circuit-switched

packet-switchedBTS

VLR

Responsible for mobilitymanagement and session

management in GPRS

Responsible for mobilitymanagement and call

control in GSM

Gs interface

This interfaceis optional!


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GPRS network operation modes

Mode Circuit Paging Channel GPRS Paging Channel Paging co-ordinationPacket Paging Channel Packet Paging Channel

I CCCH Paging Channel CCCH Paging Channel YesPacket Data Channel Not Applicable

II CCCH Paging Channel CCCH Paging Channel NoIII CCCH Paging Channel Packet Paging Channel No

CCCH Paging Channel CCCH Paging Channel

Network operation mode, NOM, in SysInfo givesfurther info about:

•paging coordination

•combined GMM/MM procedures

•Availability of class B MS in Packet Transfer mode


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Thank you for your attention

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http://www.rohde-schwarz.comor

[email protected]

Further questions:

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GPRS Scenarios - pudn.comread.pudn.com/.../ebook/733566/GPRS/cd-rom-training_GPRS_scenari… · GPRS Scenarios 1MAT 08.10.02 ... Location Update procedures Lots of LA-procedures initiated