129339363 3g Sgsn Sgn3 Periodic Rau Improvement Rs

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REQUIREMENT SPECIFICATION

3G-SGSN SGN3 PERIODIC ROUTING AREA UPDATE BEHAVIOUR IMPROVEMENT RS

Owner: Jarmo Parviainen Author: Timo LeppäkorpiStatus: ApprovedVersion: 2.0Document ID: Document IDLocation: PIKeywords: 3G-SGSN, RAU, paging

Document description

This document describes the improved behaviour of the 3G-SGSN in a case whenthe UE is out of radio coverage when the periodic routing area update shouldhappen.

Approved by

20.2.2003 Jarmo Parviainen



REQUIREMENT SPECIFICATION 2 (19)

NET/IMN/Hki Site/PaCo PDO v. 2.0T.Leppäkorpi 20.2.2003

CONTENTS

REQUIREMENT SPECIFICATION......................................................................................1

SCOPE OF THE DOCUMENT ............................................................................................ 3

1 INTRODUCTION ................................................................................................................4

2 REFERENCES ...................................................................................................................5

3 TERMS AND ABBREVIATIONS ....................................................................................... 6

4 SYSTEM DEFINITION .......................................................................................................7

5 REQUIREMENTS FOR FEATURE ................................................................................... 8

6 DESCRIPTION OF THE FEATURE ..................................................................................9

7 REQUIREMENTS FOR SW IMPLEMENTATION ...........................................................10

8 EFFECTS ON CAPACITY AND HW ...............................................................................12

9 EFFECTS ON USERINTERFACES ................................................................................13

10 ADDITIONAL INFORMATION FOR TESTING OF FEATURE .....................................14

11 DOCUMENTATION .......................................................................................................15

12 CONTACT INFORMATION ..........................................................................................16

13 FURTHER DEVELOPMENT .........................................................................................17

14 WORK AMOUNT ESTIMATES .....................................................................................18

15 DOCUMENT HISTORY .................................................................................................19

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0. SCOPE OF THE DOCUMENT

The purpose of this document is to define the effects of Periodic Routing Area

Update Improvement to Nokia Packet Core SGSN. The Periodic Routing AreaUpdate Improvement is related to 3GPP release 4. The Requirement Specificationdescribes the implementation alternative at detailed level of component interfacesand component functionality at logical level.






1 INTRODUCTION

This feature makes possible for operator to configure the time how long the PDP

contexts are kept after expiry of MS reachable timer if the mobile is out of coverage.






2 REFERENCES

2.1 External References

/1/ 3GPP TS 23.060 v.4.7.0

/2/ 3GPP TS 24.008 v.4.9.0

2.2 Internal References

/A/ PDC00298

/B/ SGN3 Release Feature Requirements






3 TERMS AND ABBREVIATIONS

3.1 Terms

MS reachable timer

Time supervision in SGSN to supervise when the Mobile Subscriber (UE) wasprevious time reachable.

3.2 Abbreviations

NMS Network Management System

RAU Routing Area Update

UE User Equipment






4 SYSTEM DEFINITION

4.1 Background and Relevant Stakeholders

This feature has been initiated internally.

4.2 Benefits for Operator

Avoiding unnecessary signalling over the radio interface.

4.3 Affected Network elements and interfaces

SGSN

NMS

4.4 Interworking features

None.

4.5 Restrictions

None.

4.6 Compliancy Information

This feature is compliant with the standards.






5 REQUIREMENTS FOR FEATURE

There was no Feasibility Study for this feature, so the requirement has taken from

the Release Feature Requirements /B/.

5.1 Requirement 1

Modified implementation:

When MS reachable timer expires, SGSN suspends paging, and PDP contexts arekept.

If UE returns to radio coverage, it will perform a routing area update, and SGSNresumes paging.

If UE does not return to radio coverage, after implementation dependent time theSGSN performs an implicit detach.






6 DESCRIPTION OF THE FEATURE

This feature makes the 3G SGSN behaviour more intelligent in case the UE is out of

coverage when it should send Periodic Routing Area Update.

3G SGSN release 3 implementation will be enhanced so that SGSN suspendspaging when MS reachable timer expires. PDP contexts are kept for a while and if UE does not return to radio coverage, the SGSN performs an implicit detach after implementation dependent time.

6.1 Current functionality

In SGN1 the SGSN adds 4 minutes to MS reachable timer and after that the pagingis suspended and the subscriber is detached if the RAU did not receive.

In SGN2 the SGSN adds 4 minutes to MS reachable timer and after that the pagingis suspended. After that the SGSN waits half of the Purge timer period until thesubscriber is detached if the RAU did not receive.

6.2 Functionality defined in standards

The UE receives the periodic RAU timer from the SGSN in the Attach Accept or RAU Accept message. Upon expiry of the periodic RAU timer, the UE shall start aperiodic routeing area update procedure. If the UE is out of coverage when theperiodic RA update timer expires, it waits until it returns to coverage (cell that

supports packet-domain services) and starts the RAU procedure after that. Defaultvalue for the periodic RAU timer is 54 min.

The SGSN has the mobile reachable timer that is slightly longer than the periodicRAU timer used by UE. The mobile reachable timer is stopped when theCONNECTED state is entered and the timer is reset and started when the statereturns to IDLE. After expiry of the mobile reachable timer, the SGSN stops pagingbut may keep the PDP contexts or perform an implicit detach. Default value for themobile reachable timer is 4 minutes greater than the periodic RAU timer (Defined in24.008 chapter 11.2.2 Timers of GPRS mobility management /2/).






7 REQUIREMENTS FOR SW IMPLEMENTATION

7.1 Mobility Management

7.1.1 Requirement 1: Use of the “PRAU timer” (Mandatory)

This requirement is based on higher level requirement 1.

Description:

The SMM has to be modified so that instead of the fixed “half of the purge timer” thenew configurable “PRAU timer” will be used.


UE SGSNRN C

Paging

Paging

MS Reachable Timer

expires: stop paging,

start PRAU timer

Paging

Paging

Routing Area Update

If the RAU comes,

stop the PRAU timer,

start MS reachable

timer and continue the

PDP contexts

Detach

If PRAU timer expires

(RAU did not come),

remove the PDP

contexts and detach

the subscriber

Detach

Routing Area Update





7.2 NMS

7.2.1 Requirement 2: Management of the “PRAU timer” (Mandatory)

This requirement is based on higher level requirement 1.

Description:

The NMS has to offer a user interface to manage the new “PRAU timer”configuration. The limits for the timer are minimum 0 and maximum 720 minutes(=12 hours) and the default is 0.






8 EFFECTS ON CAPACITY AND HW

The longer the “PRAU timer” is set, the more it takes resources because the PDP

contexts are kept longer. On the other hand some signaling is saved if the mobilereturns to coverage and the PDP contexts do not need to be re-activated.






9 EFFECTS ON USERINTERFACES

9.1 Effects on Operator Interfaces

The operator can control the “PRAU timer” by the NMS.

9.2 Effects on Subscriber Interfaces

None.






10 ADDITIONAL INFORMATION FOR TESTING OF FEATURE

It has to be ensured that if the UE returns to coverage after the MS reachable timer

has been expired but before the “PRAU timer” has been expired, the paging isresumed and the PDP contexts will remain.

If the “PRAU timer” expires, an implicit detach is performed.

The limits of the “PRAU timer” should be tested.






11 DOCUMENTATION

3G SGSN Session and Mobility Management Feature Description has to be updated

to describe the “essence of the new functionality”. This RS is actually a good sourcematerial.

3G SGSN Installation and Configuration manual has to be updated to describe thenew configuration parameter.






12 CONTACT INFORMATION

Juha Hyttinen / IS Author (SMM implementation)

Marko Kuosmanen / Implementation CM

Miska Mäkelä / Functional Testing

Timo Siponen / Product Manager

Jarmo Parviainen / Development Project Manager






13 FURTHER DEVELOPMENT






14 WORK AMOUNT ESTIMATES

Implementation (IS+SI+MT): 40h

Functional Testing: 25h

Documentation:

NMS:






15 DOCUMENT HISTORY

DATE: 17.1.2003 ISSUE: v 0.1AUTHOR: Timo Leppäkorpi

Summary of the main changes: • first draft

DATE: 20.2.2003 ISSUE: v 1.0AUTHOR: Timo Leppäkorpi Approved by: Jarmo Parviainen

Summary of the main changes: • review changes made

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129339363 3g Sgsn Sgn3 Periodic Rau Improvement Rs