ura-cell update description(2008!05!30)

RAN

URA/Cell Update Description Issue 01

Date 2008-05-30

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ii Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd

Issue 01 (2008-05-30)

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RAN URA/Cell Update Description Contents

Issue 01 (2008-05-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd

i

Contents

1 URA/Cell Update Change History..........................................................................................1-1

2 URA/CELL Update Introduction.............................................................................................2-1

3 URA/Cell Update Principles ....................................................................................................3-1 3.1 Basic Types of URA/Cell Update..................................................................................................................3-2

3.1.1 Periodical URA/Cell Update................................................................................................................3-2 3.1.2 URA/Cell Update due to Cell Reselection...........................................................................................3-2 3.1.3 Cell Update due to Paging Response ...................................................................................................3-3 3.1.4 Cell Update due to Uplink Data Transmission.....................................................................................3-3 3.1.5 Cell Update due to Radio Link Failure ................................................................................................3-3 3.1.6 Cell Update due to Re-entering Service Area ......................................................................................3-3 3.1.7 Cell Update due to RLC Unrecoverable Error .....................................................................................3-4 3.1.8 Cell Update due to MBMS ptp RB Request ........................................................................................3-4 3.1.9 Cell Update due to MBMS Reception .................................................................................................3-4

3.2 Signaling procedure of URA/Cell Update.....................................................................................................3-4 3.2.1 Signaling Procedure of URA Update ...................................................................................................3-4 3.2.2 Signaling Procedure of Cell Update.....................................................................................................3-7

4 URA/Cell Update Reference Documents ..............................................................................4-1

RAN URA/Cell Update Description 1 URA/Cell Update Change History


1-1

1 URA/Cell Update Change History

URA/Cell Update Change History provides information on the changes between different document versions.

Document and s

T nt and versions

Product Version

able 1-1 Docume product

Document Version RAN Version RNC Version NodeB Version

01 (2008-05-30) 10.0 V200R010C01B051 V100R010C01B049V200R010C01B040

Draft (2008-03-20) 10.0 V200R010C01B050 V100R010C01B045

version.

Editorial change: refers to the change in the information that was inappropriately bed in the earlier version.

01(2008-05-30) This is the document for the first commercial release of RAN10.0.

C d with draft (2008-03-20) of RAN10.0, issue 01 (2008-05-30) of RANinc ates the changes described in the following table.

There are two types of changes, which are defined as follows:

Feature change: refers to the change in the URA/cell update feature of a specific product

described or the addition of the information that was not descri

ompareorpor

10.0

Change Type

Change Description Parameter Change

Feature change

n None No e

1 URA/Cell Update Change History RAN

URA/Cell Update Description

1-2 Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd

Issue 01 (2008-05-30)

Editorial General documentation change: None change The URA/Cell Update Parameters is removed because of

the creation of RAN10.0 parameter reference. The structure is optimized.

Draft(2008-03-2T d AN10.

Compared w 008-01-20) of RAN6.1, this issue makes the following changes:

0) his is the raft of the document for first commercial release of R

ith issue 03 (2

0.

Change Type

Change Description Parameter Change

Feature change

None. Two cell update triggering causes are added due to support of MBMS. See 2.1 URA/Cell Update Introduction.

The document for feature URA update and feature cell update is combined in this document.

The parameter tables describing the URA/cell update parameters are moved to 3.3 URA/Cell Update Parameters, and the corresponding hyperlinks are provided.

Implementing information has been moved to a separate document. For information on how to implementing

None.

URA/cell update, please refer to Configuring URA/CellUpdate in RAN Feature Configuration Guide.

The description of cell update due to re-entering the service area is modified. See Cell Update due to Re-entering Service Area.

cription of The desT316 is added.

Editorial change

The description of the evaluation principle of frequent cell updates is added. See URA/Cell Update due to Cell Reselection.

les ng

parameters are added: Cell reselection timerCell reselection counter

The parameter tabof the followi

RAN URA/Cell Update Description 2 URA/CELL Update Introduction


2-1

2 URA/CELL Update Introduction

Basically, URA/cell update is used by the UE to report the location information and statusthe UE. The reporting method is classified into two types: periodical URA/cell update and cell-reselection-triggered update. URA update occurs when UE is in URA_PCH state, and cupdate occurs when UE is in CELL_PCH state or CELL_FACH state.

of

ell

, or URA_PCH state.

ables the UTRAN to manage the UE behaviors. It can be applied to bb

The

e URA where the UE is camping if URA changes election.

the cells that are in the active set after cell

H or URA_PCH state to CELL_FACH state

E to require the uplink data transmission to transit from CELL_PCH or

on

LL_PCH, and CELL_FACH states and the UEs that are interested in receiving an MBMS transmission.

Additionally, cell update is also used to perform some other functions, such as UE state transition and radio link re-establishment on the DCH. As a result, cell update may happen when the UE is in CELL_DCH, CELL_FACH, CELL_PCH

URA/cell update enmo ility management, cell reselection, and paging procedures. In detail, URA/cell update ena les the UTRAN, the UE, or the RNC to do as follows.

URA update:

Enables the UTRAN to periodically monitor the status of the UE in URA_PCH state. Enables the UTRAN to know in time thafter cell res

Enables the UE to retrieve a new URA identity after reselecting a cell that does not belong to the currently assigned URA.

The cell update:

Enables the UTRAN to periodically monitor the status of the UE in CELL_FACH or CELL_PCH state. Enables the UTRAN to know the cell where the UE is camping after the UE in CELL_PCH, URA_PCH or CELL_FACH state re-enters the service area. Enables the UTRAN to know in timereselection. Enables the UE to transit from CELL_PCwhen the network is paging the UE. Enables the UURA_PCH state to CELL_FACH state. Enables the UE that fails to establish the radio link to re-establish the RRC connection the DCH. Enables the RNC to release the RRC connection of the UE or to re-establish an RLC entity in case of RLC unrecoverable error. Enables the UTRAN to count the number of UEs in URA_PCH, CE

2 URA/CELL Update Introduction RAN



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Notifies the UTRAN of the UEs that are interested in receiving an MBMS when the UEis triggered in the URA_PCH , CELL

_PCH or CELL_FACH state

Enables the UEs to request the MBMS ptp RB setup when the UEs are in CELL_PCH, URA_PCH, or CELL_FACH states.

Impact

ease the signaling load of a network and consume more power E.

Features

Network Elemell update.

T 2-1 lv ll u

Impact On System Performance

Frequent cell update may incrsupply from the battery of a U

Impact On Other

None.

ents Involved Table 2-1 describes the NEs involved in c

able NEs invo ed in ce pdate

UE NodeB RNC MSC Server MGW SGSN GGSN HLR

√ √ √ – – – – –

N

, MSC Server = Mobile Service Switching Center Server, MGW = Media Gateway, SGSN = Serving GPRS Support Node, GGSN = Gateway GPRS Support Node, HLR = Home Location Register

OTE: –: not involved √: involved

UE = User Equipment, RNC = Radio Network Controller

RAN URA/Cell Update Description 3 URA/Cell Update Principles


3-1

3 URA/Cell Update Principles

About Thi

T ten

s Chapter

he following table lists the con ts of this chapter.

Section Describes

3.1 Basic Types of URA/Cell This describes the basic types of URA/cell update, Update including the periodical URA/cell update and the

URA/cell update due to cell reselection. Besides, cell update also has several other types.

3.2 Signaling procedure of URA/Cell Update

The signaling procedure of URA update and cell update is similar. The signaling procedure for cell update also includes cell update due to radio link failure.

3 URA/Cell Update Principles RAN



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3.1 Basic Types of URA/Cell Update This describes the basic types of URA/cell update, including the periodical URA/cell update and the URA/cell update due to cell reselection. Besides, cell update also has several other types.

3.1.1 Periodical URA/Cell Update Once the UE enters the CELL_FACH, CELL_PCH or URA_PCH state, it starts the timer T305. If the timer T305 expires, the UE performs URA/cell update with the cause "periodical URA/Cell update". URA update occurs when the UE is in URA_PCH state. Cell update occurs when the UE is in CELL_FACH or CELL_PCH state. The value of T305 is set through the parameter Timer 305 on the RNC side. The UE obtains the value of T305 from SIB1.

Accordingly, the RNC starts an internal timer for the UE in CELL_FACH, CELL_PCH or URA_PCH state. The value of this timer is greater than that of T305. When the RNC receives a URA/CELL UPDATE message with the cause "periodical URA/cell update", it restarts the internal timer. If the RNC does not receive a URA/CELL UPDATE message before expiry of the internal timer, the RNC judges that the UE is out of service, and then initiates the RRC connection release procedure.

3.1.2 URA/Cell Update due to Cell Reselection If a UE in CELL_FACH or CELL_PCH state reselects a new cell, the UE performs cell update with the cause "cell reselection". If a UE in URA_PCH state reselects a new cell with a different URA, the UE performs URA update with the cause "change of URA". Upon reception of a URA/CELL UPDATE message with the cause "Change of URA/Cell reselection", the RNC updates the URA/cell where the UE camps.

The URA ID can be assigned to a cell through the parameter URA ID. The URA ID should be created through the MML command ADD URA before being assigned to a cell.

The main parameters involved in the cell reselection algorithm when the UE is in CELL_FACH, CELL_PCH, or URA_PCH state are listed as follows:

Hysteresis 1 for connect mode Hysteresis 2 for connect mode Cell Sel-reselection quality measure Min quality level

If you want to set cell reselection parameters for each UE state (URA_PCH,CELL_PCH,CELL_FACH) respectively, you can use MML command ADD CELLSELRESEL to set them.

Hysteresis 1 for UE in CELL_PCH or URA_PCH state Hysteresis 1for UE in CELL_FACH state Hysteresis 2 for UE in CELL_PCH or URA_PCH state Hysteresis 2 for UE in CELL_FACH state Reselection delay time for UE in PCH state Reselection delay time for UE in CELL_FACH state

For details about the cell reselection procedure, refer to Cell Reselection.



3-3

In some occasions, the UE in Cell_PCH state performs cell reselection frequently and initializes the cell update procedure frequently. When the RNC detects this status of the UE, it enables the UE to transfer to the URA_PCH state through the message "CELL UPDATE CONFIRM". If the number of cell update procedures initialized by the UE within an evaluation period exceeds the threshold, the RNC judges that the UE is in frequent cell reselection state. The evaluation period and the threshold can set through the following parameters:

Cell reselection timer Cell reselection counter

3.1.3 Cell Update due to Paging Response If the UE in URA_PCH or CELL_PCH state receives a PAGING TYPE 1 message, it performs cell update with the cause "paging response". Upon reception of a CELL UPDATE message with this cause, the RNC sends a CELL UPDATE CONFIRM message to the UE and switches the UE to the CELL_FACH state.

3.1.4 Cell Update due to Uplink Data Transmission If the UE in URA_PCH or CELL_PCH state has uplink data to be transmitted, it performs cell update with the cause "uplink data transmission". Upon reception of a CELL UPDATE message with the this cause, the RNC sends a CELL UPDATE CONFIRM message to the UE and switches the UE to the CELL_FACH state.

3.1.5 Cell Update due to Radio Link Failure If the UE in CELL_DCH state detects that the criteria for radio link downlink failure is met, the UE performs cell update with the cause "radio link failure". Upon reception of a CELL UPDATE message with this cause, the RNC deletes the current radio link, re-establishes a new radio link, and sends a CELL UPDATE CONFIRM message to the UE with the parameters of the new radio link. Then, the UE re-establishes the RRC connection on the new radio link.

The criteria for radio link failure involves some timers and constants. A timer (T313) is started after the UE detects a certain number (N313) of consecutive "out of sync" indications from L1. If there is no enough number (N315) of consecutive "in sync" indications received from L1 before the timer (T313) expires, the UE considers radio link failure. Related parameters are as follows:

Timer 313 Constant 313 Constant 315

3.1.6 Cell Update due to Re-entering Service Area When the UE is in CELL_FACH, CELL_PCH, or URA_PCH state is out of service area and re-enters the service area before T307 or T317 expires, the UE performs cell update with the cause "re-entering service area". Upon reception of a CELL UPDATE message with this cause, the RNC updates the cell where the UE camps.

T305 is started as soon as the UE enters the CELL_FACH, CELL_PCH, or URA_PCH state. T307 is started when T305 expires and the UE detects "out of service area". For details, refer to Timer 307.




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T316 is started after the UE detects "out of service area" in URA_PCH or CELL_PCH state. T317 is started when T316 expires or the UE detects "out of service area" in CELL_FACH state. T317 never expires and so this parameter need not be set. For details about T316, refer to Timer 316.

3.1.7 Cell Update due to RLC Unrecoverable Error If the UE detects an RLC unrecoverable error in an AM RLC entity, the UE performs cell update with the cause "RLC unrecoverable error".

If the CELL UPDATE message indicates that this error occurred on RB2, RB3, or RB4 in the UE, the RNC releases the RRC connection of the UE.

If the CELL UPDATE message indicates that this error occurred on RBn (n>4) in the UE, the RNC re-establishes an RLC entity for the corresponding RBn.

3.1.8 Cell Update due to MBMS ptp RB Request If the UE is in Cell_FACH, Cell_PCH or URA_PCH state and the UE shall perform cell update for MBMS ptp radio bearer request, the UE performs cell update with the cause "MBMS ptp RB request".

3.1.9 Cell Update due to MBMS Reception If the UE is in Cell_FACH, Cell_PCH, or URA_PCH state and shall perform cell update for MBMS counting, the UE performs cell update with the cause "MBMS reception".

3.2 Signaling procedure of URA/Cell Update The signaling procedure of URA update and cell update is similar. The signaling procedure for cell update also includes cell update due to radio link failure.

3.2.1 Signaling Procedure of URA Update This describes the basic signaling procedure of URA update and the signaling procedure of URA update with SRNS relocation.

Basic Signaling Procedure of URA Update Figure 3-1 shows the basic signaling procedure of URA update.



3-5

Figure 3-1 Basic signaling procedure of URA update

The basic signaling procedure is as follows:

The UE sends the RNC a URA UPDATE message with the update cause "periodical URA update" or "change of URA" in the "URA update cause" information element (IE).

The RNC responds to the "URA update cause" IE and then sends a URA UPDATE CONFIRM message to the UE.

Signaling Procedure of URA Update with SRNS Relocation Figure 3-2 shows the signaling procedure of the inter-RNS URA update with SRNS relocation from RNC 1 to RNC 2.




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Figure 3-2 Signaling procedure of URA update with SRNS relocation

The UE in URA_PCH state establishes an RAB on RNC 1. In this procedure, RNC 1 is the Serving RNC (SRNC) and RNC 2 is the Drift RNC (DRNC).

The signaling procedure is as follows:

Step 1 The UE in URA_PCH state sends RNC 2 a URA UPDATE message after URA reselection.

Step 2 RNC 2 allocates a C-RNTI (used to identify the UE in CRNC) and a D-RNTI (used to identify the UE in DRNC) for the UE after receiving the URA UPDATE message from CCCH. Then, RNC 2 sends RNC 1 an UPLINK SIGNALLING TRANSFER INDICATION message, which includes target RNC-ID, allocated C-RNTI, and D-RNTI.

Step 3 RNC 1 sends the CN a RELOCATION REQUIRED message, requesting SRNS relocation.

Step 4 The CN sends a RELOCATION REQUEST message to RNC 2.

Step 5 RNC 2 prepares L2 resources for RNC 1 relocation and then sends a RELOCATION REQUEST ACKNOWLEDGE message to the CN.

Step 6 The CN sends RNC 1 a RELOCATION COMMAND message, notifying RNC 1 that SRNS relocation starts.

Step 7 RNC 1 completes related preparations such as stopping signaling and traffic RLCs. Then, RNC 1 sends a RELOCATION COMMIT message to RNC 2.

Step 8 RNC 2 sends the CN a RELOCATION DETECT message, notifying the CN that the relocation starts. Then, RNC 2 performs related operations such as L2 configuration.



3-7

Step 9 RNC 2 sends the UE a URA UPDATE CONFIRM message in the new cell. The message includes the old S-RNTI and SRNC ID as well as the new S-RNTI, SRNC-ID, and C-RNTI.

Step 10 The UE sends an RRC message UTRAN MOBILITY INFORMATION CONFIRM to RNC 2.

Step 11 RNC 2 sends a RELOCATION COMPLETE message to the CN.

Step 12 RNC 2 sends the UE a UE CAPABILITY ENQUIRY message, querying the capability information about the UE.

Step 13 The UE sends RNC 2 a UE CAPABILITY INFORMATION message, including the capability information about the UE.

Step 14 RNC 2 receives the UE CAPABILITY INFORMATION message and sends a UE CAPABILITY INFORMATION CONFIRM message to the UE.

Step 15 RNC 2 sends the UE a UTRAN MOBILITY INFORMATION message, notifying the UE of the new UTRAN information.

Step 16 The UE sends a UTRAN MOBILITY INFORMATION CONFIRM message to RNC 2.

Step 17 The CN sends RNC 1 an IU RELEASE COMMAND message, requesting RNC 1 to release the Iu interface resource related to this UE.

Step 18 RNC 1 sends an IU RELEASE COMPLETE message to the CN.

----End

3.2.2 Signaling Procedure of Cell Update This describes the basic signaling procedure for cell update, in addition to the signaling procedures for the cell update with SRNS reselection and the cell update due to radio link failure.

Basic Signaling Procedure for Cell Update Figure 3-3 shows the basic signaling procedure for cell update.

Figure 3-3 Basic signaling procedure for cell update

The basic signaling procedure is described as follows:

Step 1 The UE sends the RNC a CELL UPDATE message with a cause in the "cell update cause" IE.




Issue 01 (2008-05-30)

Step 2 The RNC performs the corresponding processing, and then sends the UE a CELL UPDATE CONFIRM message.

Step 3 According to related IEs in the received message, the UE may respond with messages or not. If the UE responds, the messages can be one of the following messages:

UTRAN MOBILITY INFORMATION CONFIRM PHYSICAL CHANNEL RECONFIGURATION COMPLETE TRANSPORT CHANNEL RECONFIGURATION COMPLETE RADIO BEARER RECONFIGURATION COMPLETE RADIO BEARER RELEASE COMPLETE

----End

If the UE changes from CELL_PCH state to URA_PCH state through cell update, the procedure is as follows:

Step 1 The UE is in CELL_PCH state and sends a CELL UPDATE message with the cause "periodical cell update".

Step 2 If the RNC decides to switch the state of this UE from CELL_PCH to URA_PCH, the RNC sends the CELL UPDATE CONFIRM message to the UE and sets the "RRC State Indicator" IE as URA_PCH. The UE enters the URA_PCH state upon reception of the CELL UPDATE CONFIRM message.

----End

Signaling Procedure for Cell Update with SRNS Relocation Figure 3-4 shows the signaling procedure for the inter-RNS cell update with SRNS relocation from RNC 1 to RNC 2.



3-9

Figure 3-4 Signaling procedure for cell update with SRNS relocation

The UE sets up an RRC connection on RNC 1. The UE is in CELL_FACH or CELL_PCH state. In this case, RNC 1 is the serving RNC (SRNC) and RNC 2 is the drift RNC (DRNC).

The signaling procedure is described as follows:

Step 1 The UE reselects a cell under RNC 2 and sends RNC 2 a CELL UPDATE message.

Step 2 RNC 2 allocates a C-RNTI and a D-RNTI for the UE. RNC 2 forwards the CELL UPDATE message received from the CCCH to RNC 1 through an UPLINK SIGNALLING TRANSFER INDICATION message. The message includes the target RNC-ID, allocated C-RNTI, and D-RNTI.

Step 3 RNC 1 sends the CN a RELOCATION REQUIRED message, requesting SRNS relocation.

Step 4 The CN sends RNC 2 a RELOCATION REQUEST message.

Step 5 RNC 2 prepares L2 resources for RNC 1 relocation, and then sends the CN a RELOCATION REQUEST ACKNOWLEDGE message.

Step 6 The CN sends RNC 1 a RELOCATION COMMAND message, notifying RNC 1 that SRNS relocation starts.




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Step 7 RNC 1 completes related preparations such as stopping signaling and traffic RLCs, and then sends RNC 2 a RELOCATION COMMIT message, requesting RNC 2 to start the relocation.

Step 8 RNC 2 sends the CN a RELOCATION DETECT message, notifying the CN that the relocation starts. Then, RNC 2 performs related operations such as L2 configuration.

Step 9 RNC 2 sends the UE a CELL UPDATE CONFIRM message in the new cell, including the old S-RNTI and SRNC ID, in addition to the new S-RNTI, SRNC-ID, and C-RNTI.

Step 10 The UE sends RNC 2 a RRC message PHYSICAL CHANNEL RECONFIGURATION COMPLETE, confirming that the relocation succeeds.

Step 11 RNC 2 sends the CN a RELOCATION COMPLETE message, allocates a new S-RNTI to the UE, and becomes the new SRNC.

Step 12 RNC 2 sends the UE a UE CAPABILITY ENQUIRY message, querying the capability information about the UE.

Step 13 The UE sends RNC 2 a UE CAPABILITY INFORMATION message, including the capability information about the UE.

Step 14 RNC 2 receives the UE CAPABILITY INFORMATION message and sends a UE CAPABILITY INFORMA CONFIRM message to the UE.

Step 15 RNC 2 sends the UE a UTRAN MOBILITY INFORMATION message, notifying the UE of the new UTRAN information.

Step 16 The UE sends RNC 2 a UTRAN MOBILITY INFORMATION CONFIRM message.

Step 17 The CN sends RNC 1 an IU RELEASE COMMAND message, requesting RNC 1 to release the Iu interface resource related to this UE.

Step 18 RNC 1 sends the CN an IU RELEASE COMPLETE message.

----End

Signaling Procedure for Cell Update due to Radio Link Failure Figure 3-5 shows the signaling procedure for cell update due to radio link failure.



3-11

Figure 3-5 Signaling procedure for cell update due to radio link failure

When receiving a cell update message, the RNC establishes a new RL that is indicated in the cell update message and deletes the old RL.

If the first attempt to re-establish the RL fails, the RRC connection will be released.

This procedure is supported for both CS and PS RAB.

For PS RAB, this procedure is supported for both DCH and HSDPA bearer.

More detailed description of this procedure is as follows:

Step 1 The UE initiates the re-establishment of the RRC connection with the new cell by sending a CELL UPDATE message on the CCCH.

Step 2 The RNC allocates radio resources in the new cell and sends an NBAP message RADIO LINK SETUP REQUEST to the new NodeB.

Step 3 The NodeB allocates resources and responds with an NBAP message RADIO LINK SETUP RESPONSE.

Step 4 The RNC initiates the setup of Iub data transport bearer by using the ALCAP protocol.

Step 5 The RNC initiates the release of Iub data transport bearer by using the ALCAP protocol and also the release of Iub radio resource by performing the NBAP RADIO LINK DELECTION procedure.

Step 6 The RNC prepares a CELL UPDATE CONFIRM message and sends it to the UE on the CCCH.

Step 7 The UE re-establishes radio connection in the new cell and sends the PHYSICAL CHANNEL RECONFIGURATION COMPLETE message to the RNC.

Additionally, if both new cell and old cell belong to one NodeB, the procedure is similar, except that the RADIO LINK SETUP procedure described above is replaced by the RADIO LINK ADDITION procedure.

----End

RAN URA/Cell Update Description 4 URA/Cell Update Reference Documents


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4 URA/Cell Update Reference Documents

URA/cell update Reference Documents lists the reference documents related to the feature.

3GPP TS 25.331 "Radio Resource Control (RRC); protocol specification" 3GPP TS 25.931 "UTRAN Functions, Examples on Signaling Procedures" 3GPP TS 25.413 "UTRAN Iu interface RANAP signaling"