UMTS Cell Selection and ReselectionReselection

ZTE University

Content

Strategy of PLMN Selection Strategy of PLMN Selection Strategy of Cell Selection and Reselection

S f Strategy of LA and RA Update Strategy of URA Update Strategy of CELL Update

Setting Up a Cell and Public Channelsg pRNC Node B UE

Process for setting up a cell

P f tti bli t i i Process for setting up public transmission channels (PRACH and SCCPCH)

Process for broadcasting system messages

UE Registers upon Switch-ong p

Strategy of PLMN Selectiongy

The USIM maintains a list of allowed PLMN types. During PLMN selection and reselection, based on the list of allowed PLMN types and a list of PLMN identities in priority order the particular PLMN may be selected eitherorder, the particular PLMN may be selected either automatically or manually. The UE will select a PLMN when it registers at power-on or re-registers after leavingwhen it registers at power on or re registers after leaving connected mode. In addition, the UE can make periodic PLMN selection.

Support for PLMN Selectionpp

The UE scans all RF channels according to its capabilities to find available PLMNs. On each carrier, the UE shall search for the strongest cell and read its system information The allowed PLMN information in USIMinformation. The allowed PLMN information in USIM determines which PLMN will be selected finally.

Whenever a UE is switched on or re-registers after leaving Whenever a UE is switched on or re-registers after leaving connected mode, it attempts to camp on the last registered PLMN. If there is no registered PLMN stored in the USIM, g ,the UE selects and attempts registration on other PLMNs using either the automatic mode or the manual mode.

Once the UE has selected a PLMN, the cell selection procedure will be performed in order to select a suitable cell of that PLMN to camp oncell of that PLMN to camp on.

PLMN Selection-Automatic Mode

Manual PLMN Selection Mode

The UE displays all PLMNs that it finds by scanning all frequency carriers. The UE displays those PLMNs that are allowed as well as those that are not allowed. The user makes a manual selection according to the availablemakes a manual selection, according to the available access technology for the chosen PLMN, and the UE attempts registration on this PLMN.attempts registration on this PLMN.

If the user selects an available PLMN in the forbidden PLMN list, the UE attempts to register and may receive a , p g ypositive acknowledgement from the CN. In this case, the PLMN is removed from the forbidden list.

Roamingg

Roaming is a service through which a UE is able to obtain services from another PLMN than the HPLMN. The behavior that the UE must follow is specified by agreements among the network operators A UE inagreements among the network operators. A UE in automatic mode, having selected and registered on a VPLMN, periodically attempts to return to its HPLMN. TheVPLMN, periodically attempts to return to its HPLMN. The time interval between consecutive attempts is stored in the USIM. The timer may have a value of between 6 minutes and 8 hours, with a step size of 6 minutes. In the absence of a fixed value, a default value of 30 minutes is used by the UEthe UE.

Content

Strategy of PLMN Selection Strategy of PLMN Selection Strategy of Cell Selection and Reselection

S f Strategy of LA and RA Update Strategy of URA Update Strategy of CELL Update

Strategy of Cell Selection and Reselectiongy

For normal service, the UE has to camp on a suitable cell, tune to that cell's control channel(s) so that the UE can: Receive system information from the PLMN;

R i i t ti i f ti f th PLMN l ti Receive registration area information from the PLMN, e.g., location area and routing area; and

Identify to which service area as specified by NAS that the serving y p y gcell belongs.

Receive other AS and NAS Information;R i i d tifi ti f th PLMN Receive paging and notification messages from the PLMN;

Initiate call setup for outgoing calls or other actions from the UE.

Cell Selection and Reselection (A)( )

To B

Cell Selection and Reselection (B)( )From A

Cell selection criteria-Rule S

Srxlev > 0 AND Squal > 0Srxlev > 0 AND Squal > 0Squal ＝ Qqualmeas － QqualminSrelev ＝ Qrxlevmeas－Qrxlevmin－Pcompensation

Qqualmeas：Measured cell quality value. The quality of the received signal expressed in CPICH Ec/N0 (dB).

Qrxlevmeas：Measured cell RX level value. The quality of the received signal expressed in CPICH RSCP (dBm)received signal expressed in CPICH RSCP (dBm).

Qqualmin：Minimum required quality level in the cell (dB). Qrxlevmin：Minimum required RX level in the cell (dBm). Pcompensation：max(UE_TXPWR_MAX_RACH－P_MAX，0) UE_TXPWR_MAX_RACH：Maximum TX power level on RACH (dBm)

P MAX M i RF t t f th UE (dB ) P_MAX：Maximum RF output power of the UE (dBm)

Camped Normally Statep y

Select and monitor the indicated PICH and PCH of the cell according to information sent in system information.

Monitor relevant system information. Perform necessary measurements for the cell reselection

evaluation procedure. Execute the cell reselection evaluation process.

Measurement rules for cell re-selection

If Sx > SIntraSearch, UE does not measure intra-frequency cells. If Sx <= Sintrasearch, UE measure intra-frequency cells. If Sintrasearch is not broadcast, UE measure intra-frequency cells.

Whether to broadcast Sintrasearch or not is controlled by SintrasearchPre. If Sx > Sintersearch, UE does not measure inter-frequency cells.

If Sx <= Sintersearch, UE measure inter-frequency cells. If Sintersearch is not broadcast UE measure inter frequency cells If Sintersearch is not broadcast, UE measure inter-frequency cells.

Whether to broadcast Sintersearch or not is controlled by SintersearchPre. If Sx > SSearchRat, UE does not measure inter-RAT cells.

If Sx <= SSearchRat, UE measure inter-RAT cells. If SsearchRat is not broadcast, UE measure inter-RAT cells. Whether to

broadcast SsearchRat or not is controlled by OtherRATInfoPre.y Where, Sx is Squal.

Cell reselection criteria-Rule R

Rs ＝ Qmeas s + Qhysts

Qmeas,s：Quality measurement result of serving cell.

Rs Qmeas,s + QhystsRn ＝ Qmeas,n－Qoffsets,n

Qmeas,s：Quality measurement result of serving cell. Qmeas,n：Quality measurement result of neighbor cell. Qhyst1s ：Hysteresis value when measurement value is CPICH RSCP. Qhyst2s ：Hysteresis value when measurement value is CPICH Ec/No. Qoffset1s,n ：Offset of two cells when measurement value is CPICH

RSCPRSCP. Qoffset2s,n ：Offset of two cells when measurement value is CPICH

Ec/No. The new cell is better ranked than the serving cell during a time interval

Treselection according to the R criteria. More than 1 second has elapsed since the UE camped on the current More than 1 second has elapsed since the UE camped on the current

serving cell.

Intra-Frequency Cell Re-Selectionq y

Inter-RAT Cell Re-Selection

Inter-RAT Cell Re-Selection

Yes

GSM→UMTS Cell Reselection Procedure

Quality measure for Cell Selection and ReselectionReselectionParameter Name QualMeasDescription This parameter indicates the quality measure for cell selection

and reselection.Range and Step 1：CPICH Ec/Nog p

2：CPICH RSCPDefault Value 1：CPICH Ec/NoC fi ti Vi >C fi ti M t >RNC NE >RNC R diConfiguration Path

View->Configuration Management->RNC NE->RNC Radio Resource Management->UltranCell->UltranCellXXX-> Cell Selection and Reselection -> Advanced Parameter Manager-> Measurement Quality for Cell Selection and ReselectionMeasurement Quality for Cell Selection and Reselection

Minimum Required Quality Level in the Cellq y

Parameter Name QQualMinDescription This parameter indicates the minimum required quality level of

the cell which satisfies the condition of being selected or reselected by UE. When the quality measure is CPICH Ec/No,

l th d lit f th ll i Q l i thonly the measured quality of the cell is over Qqualmin can the cell be selected. It’s -18dB by default.If value of the parameter is increased, it’s harder for the cell to satisfy the condition of b i l t d If l f th t i d d it’being selected.If value of the parameter is decreased, it’s easier for the cell to satisfy the condition of being selected.

Range and Step ［-24，0］dB step 1dBDefault Value -18dBConfiguration Path

View->Configuration Management->RNC NE->RNC Radio Resource Management->UtranCell->UtranCellXX->CellPath Resource Management->UtranCell->UtranCellXX->Cell Selection and Reselection-> Cell Selection and ReselectionX-> Modify Advanced Parameter-> Minimum Required Quality Level in the Cell (Qqualmin)Level in the Cell (Qqualmin)

Minimum Required Received Level in the Cellq

Parameter Name QRxLevMinDescription This parameter indicates the minimum required received

power level of the cell which satisfies the condition of being selected or reselected by UE. When the quality measure is CPICH RSCP l th d i d l l f thCPICH RSCP, only the measured received power level of the cell is over Qrxlevmin can the cell be selected.If value of the parameter is increased, it’s harder for the cell to satisfy the

diti f b i l t d If l f th t icondition of being selected.If value of the parameter is decreased, it’s easier for the cell to satisfy the condition of being selected.

Range and Step ［-115，-25］dBm step 2dBmDefault Value -115dBmConfiguration View->Configuration Management->RNC NE->RNC RadioConfiguration Path

View->Configuration Management->RNC NE->RNC Radio Resource Management->UtranCell->UtranCellXX->Cell Selection and Reselection-> Cell Selection and ReselectionX-> Modify Advanced Parameter-> Minimum Required Received> Modify Advanced Parameter > Minimum Required Received Level in the Cell (Qrxlevmin)

Maximum Allowed UL TX Power of RACH

Parameter Name MaxRACHTxPwrDescription This parameter indicates the maximum allowed UL

transmission power of RACH.If value of configuration is increased, the maximum allowed UL transmission power of RACH i If l f fi ti i d d thRACH increases.If value of configuration is decreased, the maximum allowed UL transmission power of RACH decreases.

Range and Step ［-50，33］dBmDefault Value 24dBmConfiguration View >Configuration Management >RNC NE >RNC RadioConfiguration Path

View->Configuration Management->RNC NE->RNC Radio Resource Management->UtranCell->UtranCellXX-> Modify Advanced Parameter->PRACH-> Maximum Allowed UL TX Power of RACH(dBm)Power of RACH(dBm)

Sintrasearch Configuration Tagg g

Parameter Name SIntraSearchPreDescription This parameter is a switch indicating whether Sintrasearch is

configured or not. If the value is False, Sintrasearch is not configured to UE, and UE performs the intra-frequency

t If th l i T S i fi d tmeasurement. If the value is True, Sintrasearch is configured to UE, and UE judges whether to perform the intra-frequency measurement.

Range and Step 0: Not configured to UE.1: Configured to UE.

Default Value 1: Configured to UE.e au t a ue Co gu ed to UConfiguration Path

View->Configuration Management->RNC NE->RNC Radio Resource Management->UtranCell->UtranCellXX->Cell Selection and Reselection-> Cell Selection and ReselectionX-Selection and Reselection-> Cell Selection and ReselectionX-> Modify Advanced Parameter-> S-intrasearch Configuration Tag

Intra-Frequency Measurement Trigger Threshold for Cell ReselectionThreshold for Cell ReselectionParameter Name Sintrasearch

Description This parameter indicates the intra-frequency measurement triggering threshold for cell reselection (Sintrasearch) used by UE to judge whether intra-frequency measurement should be performed. When HCS is not used if the quality of serving cell exceeds Si t h UE may choose toused, if the quality of serving cell exceeds Sintrasearch, UE may choose to not perform intra-frequency measurement. If the quality of serving cell is not larger than Sintrasearch or if Sintrasearch is not configured, UE performs intra-frequency measurement. Sintrasearch is delivered to the UE, if its value is increased, it’s easier for the UE to trigger intra-frequency measurement. If value of the parameter is decreased, it’s harder for the UE to trigger intra-frequency measurement.

R d St ［0 20］dB St 2dBRange and Step ［0，20］dB Step 2dB

Default Value 14dB

Configuration Path View->Configuration Management->RNC NE->RNC Radio ResourceConfiguration Path View Configuration Management RNC NE RNC Radio Resource Management->UtranCell->UtranCellXX->Cell Selection and Reselection-> Cell Selection and ReselectionX-> Modify Advanced Parameter-> Intra-Frequency Measurement Trigger Threshold for Cell R l ti (S )Reselection (Sintrasearch)

Sintersearch Configuration Tagg g

Parameter Name SInterSearchPreDescription This parameter is a switch which indicates whether Sintersearch

is configured or not. If the value is False, Sintersearch is not configured to UE, and UE performs the inter-frequency

t If th l i T S i fi d tmeasurement. If the value is True, Sintersearch is configured to UE, and UE judges whether to perform the inter-frequency measurement.

Range and Step 0: Not configured to UE.1: Configured to UE.

Default Value 1: Configured to UE.e au t a ue Co gu ed to UConfiguration Path

View->Configuration Management->RNC NE->RNC Radio Resource Management->UtranCell->UtranCellXX->Cell Selection and Reselection-> Cell Selection and ReselectionX-Selection and Reselection-> Cell Selection and ReselectionX-> Modify Advanced Parameter-> S-intersearch Configuration Tag

Inter-Frequency Measurement Trigger Threshold for Cell ReselectionThreshold for Cell ReselectionParameter Name Sintersearch

Description This parameter indicates the inter-frequency measurement triggering threshold for cell reselection (Sintersearch) used by UE to judge whether inter-frequency measurement should be performed. When HCS is not used if the quality of serving cell exceeds Si t h UE may choose toused, if the quality of serving cell exceeds Sintersearch, UE may choose to not perform inter-frequency measurement. If the quality of serving cell is not larger than Sintersearch or if Sintersearch is not configured, UE performs inter-frequency measurement. When Sintersearch is delivered to the UE, if its value is increased, it’s easier for the UE to trigger inter-frequency measurement. If value of the parameter is decreased, it’s harder for the UE to trigger inter-frequency measurement.

R d St ［0 20］dB St 2dBRange and Step ［0，20］dB Step 2dB

Default Value 10dB

Configuration Path View->Configuration Management->RNC NE->RNC Radio ResourceConfiguration Path View Configuration Management RNC NE RNC Radio Resource Management->UtranCell->UtranCellXX->Cell Selection and Reselection-> Cell Selection and ReselectionX-> Modify Advanced Parameter-> Inter-Frequency Measurement Trigger Threshold for Cell R l ti (S )Reselection (Sintersearch)

Inter-system Information Configuration Tagy g g

Parameter Name OtherRATInfoPreDescription This parameter is a switch indicating whether inter-RAT

information parameters used for cell reselection are configured or not. If the value is False, inter-RAT information

t t fi d t UE d UE f thparameters are not configured to UE, and UE performs the inter-RAT measurement. If the value is True, inter-RAT information parameters are configured to UE, and UE judges

h th t f th i t RAT twhether to perform the inter-RAT measurement.Range and Step 0: Not configured to UE.

1: Configured to UE.Default Value 1: Configured to UE.Configuration Path

View->Configuration Management->RNC NE->RNC Radio Resource Management->UtranCell->UtranCellXX->CellPath Resource Management->UtranCell->UtranCellXX->Cell Selection and Reselection-> Cell Selection and ReselectionX-> Modify Advanced Parameter-> Inter-system Information Configuration TagConfiguration Tag

Inter-System Measurement Trigger Threshold for Cell Reselectionfor Cell ReselectionParameter Name Ssearch,RAT

Description This parameter indicates the inter-RAT measurement triggering threshold for cell reselection (Ssearch,RAT) used by UE to judge whether inter-RAT measurement should be performed. When HCS is not used, if the quality of serving cell exceeds S h RAT UE may choose to notif the quality of serving cell exceeds Ssearch,RAT, UE may choose to not perform inter-RAT measurement. If the quality of serving cell is not larger than Ssearch,RAT or if Ssearch,RAT is not configured, UE performs inter-RAT measurement. When Ssearch,RAT is delivered to the UE, if its value is increased, it’s easier for the UE to trigger inter-RAT measurement. If value of the parameter is decreased, it’s harder for the UE to trigger inter-RAT measurement.

R d St ［0 20］dB St 2dBRange and Step ［0，20］dB Step 2dB

Default Value 6dB

Configuration Path View->Configuration Management->RNC NE->RNC Radio ResourceConfiguration Path View Configuration Management RNC NE RNC Radio Resource Management->UtranCell->UtranCellXX->Cell Selection and Reselection-> Cell Selection and ReselectionX-> Modify Advanced Parameter-> Inter-System Measurement Trigger Threshold for Cell R l ti (S )Reselection (Ssearch,RAT)

Reselection Hysteresis 1 of Serving Celly g

Parameter Name Qhyst1s

Description This parameter indicates the hysteresis value for FDD cells in case the quality measure for cell selection and reselection is set to CPICH RSCP. In cell-ranking criterion R of cell

l ti th R l f i ll l t th dreselection, the R value of serving cell equals to the measured value plus the hysteresis value. If value of the parameter is increased, it’s harder to trigger cell reselection as the R value

f th i ll ill i If l f th t iof the serving cell will increase. If value of the parameter is decreased, it’s easier to trigger cell reselection as the R value of the serving cell will decrease.

Range and Step ［0，40］dB step 2dBDefault Value 10dBConfiguration View->Configuration Management->RNC NE->RNC RadioConfiguration Path

View->Configuration Management->RNC NE->RNC Radio Resource Management->UtranCell->UtranCellXX->Cell Selection and Reselection-> Cell Selection and ReselectionX-> Modify Advanced Parameter-> Reselection Hysteresis 1 of> Modify Advanced Parameter > Reselection Hysteresis 1 of Serving Cell (Qhyst1s)

Reselection Hysteresis 2 of Serving Celly g

Parameter Name Qhyst2s

Description This parameter indicates the hysteresis value for FDD cells in case the quality measure for cell selection and reselection is set to CPICH Ec/No. In cell-ranking criterion R of cell

l ti th R l f i ll l t th dreselection, the R value of serving cell equals to the measured value plus Qhyst2s. If value of the parameter is increased, it’s harder to trigger cell reselection as the R value of the serving

ll ill i If l f th t i d d it’cell will increase. If value of the parameter is decreased, it’s easier to trigger cell reselection as the R value of the serving cell will decrease.

Range and Step ［0，40］dB step 2dBDefault Value 2dBConfiguration View->Configuration Management->RNC NE->RNC RadioConfiguration Path

View->Configuration Management->RNC NE->RNC Radio Resource Management->UtranCell->UtranCellXX->Cell Selection and Reselection-> Cell Selection and ReselectionX-> Modify Advanced Parameter-> Qhyst2 (dB)> Modify Advanced Parameter > Qhyst2s (dB)

Quality Offset 1 Between Serving Cell and Neighbo ring CellNeighbouring CellParameter Name Qoffset1s,n

Description This parameter indicates the quality offset of the serving cell and neighbor cell when the quality measure is CPICH RSCP. This parameter is required when queues cells in the cell reselection rule. This parameter is broadcast to UE in SIB11 R of neighbor cell =This parameter is broadcast to UE in SIB11. R of neighbor cell = measured signal quality of neighbor cell - this offset. If value of the parameter is increased, it’s harder to trigger cell reselection as the R value of the neighbor cell will decrease. If value of the parameter is decreased, it’s easier to trigger cell reselection as the R value of neighbor cell will probably increase.

Range and Step OMCR：［-50，50］dBRNC D P 50 ［0 100］RNC：D=P+50，［0，100］

Default Value 0dB

Configuration Path View->Configuration Management->RNC NE->RNC Radio Resource g g gManagement->UltranCell->UltranCellXXX->Neighbouring Cell -> Advanced Parameter Manager-> Quality Offset 1(Qoffset1s,n ) Between Serving Cell and Neighbouring Cell Broadcasted in SIB11

Quality Offset 2 Between Serving Cell and Neighbo ring CellNeighbouring Cell Parameter Name Qoffset2s,n

Description This parameter indicates the quality offset of the serving cell and neighbor cell when the quality measure is CPICH Ec/No. This parameter is required when queues cells in the cell reselection rule. This parameter is broadcast to UE in SIB11 R of neighbor cell =This parameter is broadcast to UE in SIB11. R of neighbor cell = measured signal quality of neighbor cell - this offset. If value of the parameter is increased, it’s harder to trigger cell reselection as the R value of the neighbor cell will decrease. If value of the parameter is decreased, it’s easier to trigger cell reselection as the R value of neighbor cell will increase.

Range and Step OMCR：［-50，50］dBRNC D P 50 ［0 100］RNC：D=P+50，［0，100］

Default Value 0dB

Configuration Path View->Configuration Management->RNC NE->RNC Radio Resource g g gManagement->UltranCell->UltranCellXXX-> Neighbouring Cell -> Advanced Parameter Manager-> Quality Offset 2(Qoffset2s,n ) Between Serving Cell and Neighbouring Cell Broadcasted in SIB11

Cell Reselection Timer Value

Parameter Name Treselections

Description This parameter indicates the cell reselection timer value. UE will reselect the new cell if the new cell is best ranked according to the criterion R during a time interval indicated by T l ti d th ll b l t d iTreselection and the new cell can be selected as new serving cell only after extension of the reselection timer. If value of the parameter is increased, it’s harder to trigger cell reselection. If

l f th t i d d it’ i t t i llvalue of the parameter is decreased, it’s easier to trigger cell reselection.

Range and Step ［0，31］s step 1sDefault Value 1sConfiguration Path

View->Configuration Management->RNC NE->RNC Radio Resource Management->UltranCell-> UtranCellXX->CellPath Resource Management->UltranCell-> UtranCellXX->Cell Selection and Reselection-> Cell Selection and ReselectionX->Advanced Parameter Manager -> Cell Reselection Timer Value (Treselection )Value (Treselections)

Cell Barred Indicator

Parameter Name CellBarredIndDescription This parameter is cell barred indicator. If the cell barred

indicator is set to “Barred”, UEs are not permitted to select/re-select this cell, even for emergency calls.

Range and Step 1: Barred2: Not Barred

Default Value 2: Not BarredDefault Value 2: Not BarredConfiguration Path

View->Configuration Management->RNC NE->RNC Radio Resource Management->UltranCell->UltranCellXXX->Cell Selection and Reselection > Cell Selection and ReselectionXSelection and Reselection -> Cell Selection and ReselectionX-> Advanced Parameter Manager-> Cell Barred Indicator

Intra-frequency Cell Reselection Indicatorq y

Parameter Name InFreqReselIndDescription This parameter is intra-frequency cell reselection indicator. If

cell is barred, if the value of this parameter is “Allowed”, UE is allowed to select other intra-frequency cell in case it satisfies th ll l ti / l ti diti If it i t “N t All d”the cell selection/relection condition. If it is set “Not Allowed”, when cell is barred, UE will not select another intra-frequency cell.

Range and Step 0: Allowed1: Not Allowed

Default Value 0: Allowede au t a ue 0 o edConfiguration Path

View->Configuration Management->RNC NE->RNC Radio Resource Management->UltranCell->UltranCellXXX-> Cell Selection and Reselection -> Cell Selection and ReselectionX-Selection and Reselection -> Cell Selection and ReselectionX-> Advanced Parameter Manager-> Intra-frequency Cell Reselection Indicator

Broadcast in either SIB11 or SIB11bis

Parameter Name Sib11orSib11bisDescription This parameter indicates UTRAN neighbour cell broadcast in

either SIB11 or SIB11bis, the default parameter is broadcast in SIB11. If there are so many neighbour cells, and the size of

t l th 3552bit l t t f llsystem message larger than 3552bit, select part of cells broadcast in SIB11bis

Range and Step 0: SIB111: SIB11bis

Default Value 0: SIB11Configuration View >Configuration Management >RNC NE >RNC RadioConfiguration Path

View->Configuration Management->RNC NE->RNC Radio Resource Management->UTRAN Cell -> UTRAN Cell xxx -> Neighbouring Cell ->Neighbouring Cell xxx -> Modify -> Broadcast in either SIB11 or SIB11bisBroadcast in either SIB11 or SIB11bis

Measurement Priority of Neighboring Celly g g

Parameter Name MeasPrioDescription This parameter indicates the measurement priority of the

neighboring cell. The highest priority is 0, the lowest priority is 2.

Range and Step ［0，2］Default Value 0C fi ti Vi >C fi ti M t >RNC NE >RNC R diConfiguration Path

View->Configuration Management->RNC NE->RNC Radio Resource Management->UTRAN Cell -> UTRAN Cell xxx ->Neighbouring Cell -> Measurement Priority of Neighboring CellCell

Content

Strategy of PLMN Selection Strategy of PLMN Selection Strategy of Cell Selection and Reselection

S f Strategy of LA and RA Update Strategy of URA Update Strategy of CELL Update

Strategy of LA and RA Updategy p

If the LAI or RAI read from system information are different from those stored in USIM before the UE switches off, the UE will perform LA or RA update. Wh th UE i IDLE d t LA RA When the UE in IDLE mode moves to a new LA or RA or PLMN, it will perform update.

The process of LA or RA update is controlled by CN and is The process of LA or RA update is controlled by CN and is transparently transmitted as the RAN is concerned.

There are three types of update: normal update periodic There are three types of update: normal update, periodic update and IMSI attach and detach.

LA and RA Structure

The LA is an area to which the CN sends a paging message for circuit switched service and the RA is an area to which the CN sends a paging message for packet switched services Each area LA or RA may consist ofswitched services. Each area, LA or RA, may consist of several cells of one or more RNC, which are connected to the same core network. Each cell could belong to only onethe same core network. Each cell could belong to only one LA and one RA.

Normal LA and RA Updatingp g

Normal update is performed when the UE moves in a cell belonging to a new LA or RA. The UE reads the LAI and the RAI in the system information and detects that one or both of the received area identities differ from the onesboth of the received area identities differ from the ones stored on the USIM. If the LAI or RAI received from the system information is not in the forbidden LAIs or RAIs list,system information is not in the forbidden LAIs or RAIs list, an LA or RA update request is sent by the UE.

Periodic LA and RA Updatingp g

Periodic LA and RA updating is used to notify the network of the UEs availability, and to avoid unnecessary paging attempts for a UE that has lost coverage and is not able to inform the CN that it is inactive The periodic LA updateinform the CN that it is inactive. The periodic LA update procedure is controlled by a timer, called t3212, whose value is sent to UEs with broadcast message. The periodicvalue is sent to UEs with broadcast message. The periodic RA update is controlled by a timer, called t3312, whose value is sent by the CN to the UE in the IMSI attach or in the routing area update message accept.

Location Update FlowSystem Information

p

RRC Connection Setup

NAS Connection

RRC Connection Release

IMSI Attach/Detach

the UE sends an “attach” or “detach” message when it is powered on or off indicating whether the UE is active or inactive. The CN avoids performing paging attempts when IMSI detach is applied and the UE is switched off WhenIMSI detach is applied and the UE is switched off. When the UE is switched on, the UE performs a location registration request, indicating IMSI attach, if it is in theregistration request, indicating IMSI attach, if it is in the same LA or RA in which it was switched off. If the registration area is changed, a normal LA update is performed by the UE.

Content

Strategy of PLMN Selection Strategy of PLMN Selection Strategy of Cell Selection and Reselection

S f Strategy of LA and RA Update Strategy of URA Update Strategy of CELL Update

Strategy of URA Updategy p

If the new cell that the UE camps on is not in the same URA area as the former cell that the UE camps on, the URA Update is triggered.Th UE t ll th t h URA d fi d Thi ill The UE enters a cell that has no URAs defined. This will trigger a release of the RRC Connection and the UE enters Idle modeIdle mode.

Process of URA Updatep

UE UTRAN

URA UPDATE

URA UPDATE CONFIRM

UE UTRANUE UTRAN

URA UPDATE

RRC CONNECTION RELEASE

Content

Strategy of PLMN Selection Strategy of PLMN Selection Strategy of Cell Selection and Reselection

S f Strategy of LA and RA Update Strategy of URA Update Strategy of CELL Update

Strategy of CELL Updategy p

Cell reselection in state CELL_FACH. Radio link failure in state CELL_DCH. T305 periodic cell update. The UE in state URA_PCH sends data in uplink. The UE in state CELL_FACH/CELL_DCH detects that an

RLC unrecoverable error of AM RLC entity.

Process of CELL Updatep

UE UTRAN

CELL UPDATE

CELL UPDATE CONFIRMCELL UPDATE CONFIRM

UE UTRAN

CELL UPDATECELL UPDATE

CELL UPDATE CONFIRM

UE UTRAN

PHYSICAL CHANNEL RECONFIGURATION COMPLETE

UE UTRAN

CELL UPDATE

CELL UPDATE CONFIRM

RADIO BEARERRECONFIGURATION COMPLETE