03 URA Update

RAN Feature Description Table of Contents

Table of Contents

Chapter 3 URA Update................................................................................................................3-1

3.1 Introduction...................................................................................................................... 3-1

3.1.1 Definition...............................................................................................................3-1

3.1.2 Purposes...............................................................................................................3-1

3.1.3 Terms and Abbreviations.......................................................................................3-1

3.2 Availability........................................................................................................................ 3-2

3.2.1 Network Elements Involved...................................................................................3-2

3.2.2 Software Releases................................................................................................3-3

3.2.3 Miscellaneous........................................................................................................3-3

3.3 Impact.............................................................................................................................. 3-3

3.3.1 On System Performance.......................................................................................3-3

3.3.2 On Other Features.................................................................................................3-3

3.4 Technical Description.......................................................................................................3-3

3.4.1 URA Update Configuration Model.........................................................................3-3

3.4.2 Basic Types...........................................................................................................3-4

3.4.3 Basic Signaling Procedure of URA Update...........................................................3-8

3.4.4 Signaling Procedure of URA Update with SRNS Relocation.................................3-8

3.5 Capabilities....................................................................................................................3-10

3.6 Implementation..............................................................................................................3-10

3.6.1 Enabling URA update..........................................................................................3-10

3.6.2 Reconfiguring Parameters...................................................................................3-10

3.6.3 Disabling URA update.........................................................................................3-11

3.7 Maintenance Information................................................................................................3-11

3.7.1 Alarms.................................................................................................................3-11

3.7.2 Counters..............................................................................................................3-12

3.8 References..................................................................................................................... 3-12

Huawei Technologies Proprietary

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RAN Feature Description List of Figures

List of Figures

Figure 3-1 URA Update Configuration Model........................................................................3-4

Figure 3-2 Basic signaling procedure for URA update..........................................................3-8

Figure 3-3 Signaling procedure for URA update with SRNS relocation.................................3-9


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RAN Feature Description List of Tables

List of Tables

Table 3-1 NEs required for URA update................................................................................3-2

Table 3-2 RAN products and related versions.......................................................................3-3

Table 3-3 Commands for the reconfiguration on the RNC side...........................................3-10

Table 3-4 URA update counters..........................................................................................3-12


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RAN Feature Description Chapter 3 URA Update

Chapter 3 URA Update

3.1 Introduction

3.1.1 Definition

The User Registration Area (URA) update is of two types:

Periodical URA update

The UE in URA_PCH state periodically performs URA update. Thus, the UTRAN

can know the position and state of the UE.

URA update triggered by URA reselection

When the UE in URA_PCH state reselects another URA, it performs URA

update with the cause "change of URA". Thus the UTRAN can know which URA

the UE is located in.

URA update procedure is initiated by the UE.

3.1.2 Purposes

URA update enables UTRAN to manage behaviors of the UE, the main benefits of

URA update are as follows:

Periodical URA update can be used as a supervision mechanism when UE in

URA_PCH state.

If the UE is in URA_PCH state, only when it moves between cells in different

URAs, will it lead to URA update triggered by URA reselection. And the UE can

retrieve a new URA identity after reselecting a cell that does not belong to the

currently assigned URA.

3.1.3 Terms and Abbreviations

I. Terms

Term Description

CELL_DCH

An RRC connected mode in which DCCH and, if configured, DTCH

are available. DCCH and DTCH are mapped to DCH. The RNC

records the cells in the active set of the UE.

CELL_FACHAn RRC connected mode in which DCCH and, if configured, DTCH

are available. DCCH and DTCH are mapped to RACH/FACH.


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Term Description

CELL_PCHAn RRC connected mode where neither DCCH nor DTCH is

available.

URA_PCHAn RRC connected mode where neither DCCH nor DTCH is

available.

II. Abbreviations

Abbreviation Full Spelling

DCCH Dedicated Control Channel

DCH Dedicated Channel

DTCH Dedicated Traffic Channel

FACH Forward Access Channel

MD Mandatory default

RACH Random Access Channel

RRC Radio Resource Control

RB Radio Bearer

SIB System Information Block

URA User Registration Area

3.2 Availability

3.2.1 Network Elements Involved

Table 3-1 describes the NEs involved with URA update.


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Table 3-1 NEs required for URA update

UE NodeB RNCMSC

Server

MG

WSGSN GGSN HLR

√ √ √ - - - - -

Note:

–: not required

√: required

Note:

This chapter describes only the availability of the NodeB and the RNC.

3.2.2 Software Releases

Table 3-2 describes the versions of RAN products that support URA update.

Table 3-2 RAN products and related versions

Product Version

RNC BSC6800 V100R002 and later releases

NodeB

DBS3800 V100R005 and later releases

BTS3812A V100R005 and later releases

BTS3812E V100R005 and later releases

3.2.3 Miscellaneous

None

3.3 Impact

3.3.1 On System Performance

None.

3.3.2 On Other Features

None.


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3.4 Technical Description

3.4.1 URA Update Configuration Model

The configuration model for URA update is as show in Figure 3-2.

RNC

RadioClass

GlobalParaClass CellClass

CELLURA.ClassCONNMODETIMER.Class

Timer 305

Timer 302

Constant 302

Timer 307

URA ID

Figure 3-2 URA Update Configuration Model

3.4.2 Basic Types

According to update causes, URA update can be divided into two types:

Periodic URA update

URA update triggered by URA reselection

I. Periodical URA Update

After entering URA _PCH state, the UE starts the timer T305. Upon the expiry of

timer T305, the UE initiates URA update with the cause “periodical URA update”.

Accordingly, the RNC starts another timer for the UE in URA_PCH state. The value of

this timer should be greater than that of timer T305. When receiving a URA UPDATE

message with the cause “periodical URA update”, the RNC restarts the timer T305 of

this UE.

If the UTRAN does not receive the URA UPDATE message upon expiry of the timer, it

regards that the UE is out of the network, and triggers RRC to release the network

side resource.


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Parameter Name Timer 305

Parameter ID T305

GUI Range INFINITY, D5, D10, D30, D60, D120, D360,

D720

Physical Range& Unit Infinity, 5, 10, 30, 60, 120, 360, 720 (min)

Default Value D10

Optional/Mandatory Optional

MML Command SET CONNMODETIMER

Description:

T305 is started after the UE receives CELL UPDATE CONFIRM or URA UPDATE

CONFIRM in CELL_FACH, URA_PCH or CELL_PCH state. T305 is stopped after

the UE enters another state.

When T305 expires, the UE transmit CELL UPDATE or URA UPDATE if T307 is

not activated and the UE detects "in service area". Otherwise, if T307 is not active,

start T307.

Configuration Rule and Restriction:

T305 should be set larger than T302*N302 (T305>T302*N302). UE can obtain the

value from SIB1.


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Parameter ID T302

GUI RangeD100, D200, D400, D600, D800, D1000, D1200,

D1400, D1600, D1800, D2000, D3000, D4000,

D6000, D8000

Physical Range& Unit 100, 200, 400, 600, 800, 1000, 1200, 1400, 1600,

1800, 2000, 3000, 4000, 6000, 8000(ms)

Default Value D2000



Description:

T302 is started after the UE sends the CELL UPDATE or URA UPDATE message

and is stopped after the UE receives the CELL UPDATE CONFIRM or URA

UPDATE CONFIRM message. The CELL UPDATE or URA UPDATE message is

resent upon the expiry of the timer if V302<= N302; otherwise, the UE enters idle

mode.

Note: V302 is a counter for UE. It is reset when the procedure Cell update or URA update is

initiated and incremented upon expiry of T302. When V302 > N302, the UE enters idle

mode.

Parameter Name Constant 302

Parameter ID N302

GUI Range 0–7

Physical Range& Unit -

Default Value 3



Description:

Maximum number of retransmissions of CELL UPDATE or URA UPDATE


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Parameter ID T307

GUI Range D5, D10, D15, D20, D30, D40, D50

Physical Range& Unit 5, 10, 15, 20, 30, 40, 50(s)

Default Value 30



Description:

T307 is started after T305 has expired and the UE detects "out of service area".

T307 is stopped after the UE detects "in service area". The UE enters idle mode

upon expiry.

II. URA Update Triggered by URA Reselection

If the UE in URA_PCH state enters a new URA, the UE performs URA update with

the cause “change of URA”.

After receiving a URA UPDATE message with the cause “change of URA”,.

Parameter Name URA ID

Parameter ID URAID

GUI Range 0–65535

Physical Range& Unit -

Default Value -

Optional/Mandatory Mandatory

MML Command ADD CELLURA

Description:

Uniquely identifying a URA. This URA ID is used for adding the UTRAN

Registration Area (URA) of a cell


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Configuration Rule and Restriction:

URA update with the cause “Change of URA” can be initiated by the UE only when

two cells are configured with different URA IDs.

URA ID can be added in advance by ADD URA command.

3.4.3 Basic Signaling Procedure of URA Update

Figure 3-3 shows the basic signaling procedure for URA update.

UE

1.URA UPDATE

2.URA UPDATE CONFIRM

RNC

Figure 3-3 Basic signaling procedure for URA update

The basic signaling procedure is described as follows:

1) The UE sends the RNC a URA UPDATE message and includes the update

cause “periodical URA update” or “change of URA” in the “URA update cause”

IE.

2) The RNC performs the corresponding processing according to the “URA update

cause” IE, and then sends a URA UPDATE CONFIRM message to the UE.

3.4.4 Signaling Procedure of URA Update with SRNS Relocation

Figure 3-1 shows the signaling procedure for the inter-RNS URA update with SRNS

relocation from RNC 1 to RNC 2.


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RNC1 RNC2CNUE

3. RELOCATION REQUIRED4. RELOCATION REQUEST

5. RELOCATION REQUEST ACK

6. RELOCATION COMMAND

9. URA UPDATE CONFIRM

8. RELOCATION DETECT

11. RELOCATION COMPLETE

2. UPLINK SIGNALLING TRANSFER INDICATION

7. RELOCATION COMMIT

10.UTRAN MOBILITY INFORMATION CONFIRM

12. IU RELEASE COMMAND

13. IU RELEASE COMPLETE

Establish RAB, in URA_PCH

1.URA UPDATE

Figure 3-1 Signaling procedure for URA update with SRNS relocation

The signaling procedure is described as follows:

The UE establishes RAB connection on RNC 1. The UE is in URA_PCH state. Here,

RNC 1 is the serving RNC (SRNC) and RNC 2 is the drift RNC (DRNC).

1) The UE in URA_PCH state sends RNC 2 a URA UPDATE message after URA

reselection.

2) RNC 2 allocates C-RNTI and D-RNTI for the UE after receiving the URA

UPDATE message from CCCH, and then sends RNC 1 an UPLINK

SIGNALLING TRANSFER INDICATION message. The message includes target

RNC-ID, allocated C-RNTI (used to identify the UE in C-RNC), and D-RNTI.

3) RNC 1 sends the CN a RELOCATION REQUIRED message, requesting SRNS

relocation.

4) The CN sends RNC 2 a RELOCATION REQUEST message

5) RNC 2 prepares L2 resources for RNC 1 relocation, and then sends the CN a

RELOCATION REQUEST ACKNOWLEDGE message.

6) The CN sends RNC 1 a RELOCATION COMMAND message, notifying RNC 1

that SRNS relocation starts.


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7) RNC 1 completes related preparations such as stopping signaling and traffic

RLCs, and then sends RNC 2 a RELOCATION COMMIT message.

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.

9) RNC 2 sends the UE a URA UPDATE CONFIRM message in the new cell,

including the old S-RNTI and SRNC ID as well as the new S-RNTI, SRNC-ID,

and C-RNTI.

10) The UE sends RNC 2 an RRC message, UTRAN MOBILITY INFORMATION

CONFIRM.

11) RNC 2 sends the CN a RELOCATION COMPLETE message.

12) The CN sends RNC 1 an IU RELEASE COMMAND message, requesting RNC 1

to release the Iu interface resource related to this UE.

13) RNC 1 sends the CN an IU RELEASE COMPLETE message.

3.5 Capabilities

None

3.6 Implementation

3.6.1 Enabling URA update

This feature does not need extra hardware or initialization. It takes effect

automatically.

For the network planning or optimization, the data can be adjusted on the RNC LMT

as required. The default values of the related parameters are recommended to be

used.

3.6.2 Reconfiguring Parameters

I. Parameter Reconfiguration on the RNC Side

Table 3-1 describes the commands used for the reconfiguration on the RNC side.

Table 3-1 Commands for the reconfiguration on the RNC side

Function Command

To query the UE timers and

constants in connected modeLST CONNMODETIMER


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Function Command

About UE timers

and constants in

connected mode

To set the UE timers and

constants in connected modeSET CONNMODETIMER

About the UE

state-transition

algorithms

To query the UE state-transition

algorithmsLST UESTATETRANS

To set the UE state-transition

algorithmsSET UESTATETRANS

About the URATo query the URA of a cell LST CELLURA

To add the URA of a cell. ADD CELLURA

II. Parameter Reconfiguration on the NodeB Side

None.

III. Examples

Before data configuration on RNC LMT, use the related LST command to check

related information. Only after recording the original data can you modify the

parameters.

//Set the period of URA update initiated by the UE in URA_PCH state to 5

minutes.

SET CONNMODETIMER: T305=D5;

//Set the Min quality level to a smaller value, such as –21, to make it

easier to reselect cell 3, for URA update with the cause “URA

reselection”.

MOD CELLSELRESEL: CELLID=3, QUALMEAS=CPICH_RSCP, QQUALMIN=-21;

//Add two URAs, and add cell 1 and cell 2 to URA 1 and URA 2.

ADD URA: URAID=1;

ADD CELLURA: CELLID=1, URAID=1;

ADD URA: URAID=2;

ADD CELLURA: CELLID=2, URAID=2;

//If the UE in CELL_PCH state initiates cell updates due to cell

reselection more than three times within 60 seconds, enable the UE to

transit to URA_PCH state if it initiates cell update again.

SET DCCC: CELLRESELECTTIMER=60, CELLRESELECTCOUNTER=3;


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3.6.3 Disabling URA update

URA update can be set and reconfigured, but not disabled.

3.7 Maintenance Information

3.7.1 Alarms

None.

3.7.2 Counters

URA update counters belong to CELL->URAUPDATE.Cell, where CELL is

measurement object type, and URAUPDATE.Cell is measurement unit.

Table 3-2 lists the URA update counters.

Table 3-2 URA update counters

Item Description

VS.URAUpd.Prd Number of URA updates due to periodic URA update

VS.URAUpd.CHG Number of URA updates due to change of URA

VS.URAUpd.Succ.PrdNumber of successful URA updates due to periodic URA

update

VS.URAUpd.Succ.CHGNumber of successful URA updates due to change of

URA

3.8 References

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"


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03 URA Update