1 wcdma ue behaviors in idle mode

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WCDMA UE Behaviors in Idle Mode

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Foreword

l UE behaviors in idle mode include :

p PLMN selection

p System information reception

p Cell selection and reselection

p Location registration

p Paging procedure

p Access procedure

l PLMN selection

Used to ensure that the PLMN selected by the UE properly provides services.

l Cell selection and reselection

Used to ensure that the UE finds a suitable cell to camp on.

l Location registration

Used for the network to trace the current status of the UE and to ensure that the UE is camped on

the network when the UE does not perform any operation for a long period.

l System information reception

The network broadcasts the network information to a UE which camps on the cell to control the

behaviors of the UE.

l Paging

Used for the network to send paging messages to a UE which is in idle mode, CELL_PCH state, or

URA_PCH state.

l Access

From the view of access stratum, access is the procedure UE shift from idle mode to connected

mode.




Contents

1. PLMN Selection

2. System Information Reception

3. Cell Selection and Reselection

4. Location Registration

5. Paging Procedure

6. Access Procedure




Cell Search

l Cell search is the first step for PLMN selection. It means UE

should find which primary scrambling code is used in the cell.

There are two scenarios for cell search:

p UE does not have UTRAN carrier information: In order to find a

suitable cell to stay, UE will scan all the frequencies in UTRAN. In

each carrier, UE just need to find a cell with best signal

p UE has UTRAN carrier information: UE will try whether the original

cell is suitable to stay. If not, UE still need to scan all the

frequencies about UTRAN in order to find a suitable cell in PLMN

l Typically the first scenario for cell search is the first time a new UE is put into use.

l The second scenario is very common.




Cell Search Procedure

Slot synchronization

Frame synchronization and code-group identification

Primary Scrambling code identification

l Step 1: Slot synchronization

During the first step of the cell search procedure the UE uses the primary synchronisation code (PSC)

to acquire slot synchronisation to a cell.

l Step 2: Frame synchronization and code-group identification

During the second step of the cell search procedure, the UE uses the secondary synchronisation

code (SSC) to find frame synchronisation and identify the code group of the cell found in the first

step.

l Step 3: Primary Scrambling code identification:

During the last step of the cell search procedure, the UE determines the exact primary scrambling

code used by the found cell. The primary scrambling code is typically identified through symbol-by-

symbol correlation over the CPICH with all codes within the code group identified in the second

step.




PLMN Selection

l When the UE is switched on or the coverage is restored, it

selects the registered PLMN. If the registered PLMN is not

available, the UE performs one of the following two procedures

depending on its operating mode:

p Automatic selection: If UE can find one or several PLMNs, it

automatically selects a PLMN according to a priority order. HPLMN

has the highest priority. The priority order of other PLMNs is

related to the setting in SIM and the signal quality of the PLMN.

p Manual selection: The UE shows all available PLMNs to the

subscriber. The subscriber can select one PLMN.

l After cell search UE can get the system information from PCCPCH (carrying BCH), and the PLMN ID

is contained in MIB (main information block) of system information.

l After getting the MIB, UE can judge weather the current PLMN is the right one. If so, UE will

continue the following procedure; if not, UE will search another carrier, do this procedure again.

l HPLMN is the PLMN which has same MCC (mobile country code) and MNC (mobile network code)

with those in the IMSI of the UE.




PLMN Selection (Cont.)

l PLMN Selection for UE in VPLMN

p If the UE is in a VPLMN, it shall periodically attempt to search its

HPLMN or higher priority PLMN listed in "user controlled PLMN

selector" or "operator controlled PLMN selector“. These two lists

are contained in SIM.

p The periodic attempts shall only be performed in automatic mode

when the UE is roaming.

l The PLMN, except the HPLMN, which the UE camps on, is VPLMN for the UE.

l For periodic attempts to searching HPLMN or higher priority PLMN, a value of T minutes may be

stored in the SIM. T is either in the range from 6 minutes to 8 hours in 6-minute steps or it indicates

that no periodic attempts shall be made. If no value is stored in the SIM, a default value of 60

minutes is used.

l The UE shall make an attempt if the UE is on the VPLMN at time T after the last attempt.




Contents

1. PLMN Selection




5. Paging Procedure

6. Access Procedure




Structure of System Information

l System information is organized as a tree, including:

p MIB (Master Information Block )

p SB (Scheduling Block )

p SIB (System Information Block )

MIB

SIB

SB

SIB

SIB

SIB

l System information is used for the network to broadcast network information to UEs camping on a

cell so as to control the behavior of UEs.

l MIB

p When selecting a new cell, the UE reads the MIB. The UE may locate the MIB by predefined

scheduling information. The IEs in the MIB includes MIB value tag, PLMN type, PLMN

identity, reference and scheduling information for a number of SIBs in a cell or one or two

SBs in a cell.

l SB

p Scheduling Block (SB) gives reference and scheduling information to other SIBs. The

scheduling information of a SIB may be included in only one of MIB and SB.

l SIB

p System Information Block (SIB) contains actual system information. It consists of system

information elements (IEs) with the same purpose.

l Scheduling information for a system information block may only be included in either the master

information block or one of the scheduling blocks.




System Information

l SIB1: Contains the system information for NAS and the timer/counter

for UE

l SIB2: Contains the URA information

l SIB3: Contains the parameters for cell selection and cell re-selection

l SIB5: Contains parameters for the common physical channels of the

cell

l SIB7: Contains the uplink interference level and the refreshing timer

for SIB7

l SIB11: Contains measurement controlling information

l SIB4: Contains parameters for cell selection and cell re-selection while UE is in connected mode

l SIB6: Contains parameters for the common physical channels of the cell while UE is in connected

mode

l SIB12: Contains measurement controlling information in connecting mode

l SIB13: Contains ANSI-41 system information

l SIB14: Contains the information in TDD mode

l SIB15: Contains the position service information

l SIB16: Contains the needed pre-configuration information for handover from other RAT to UTRAN

l SIB17: Contains the configuration information for TDD

l SIB18: Contains the PLMN identities of the neighboring cells

p To be used in shared networks to help with the cell reselection process




Reception of System Information

l The UE shall read system information broadcast on a BCH

transport channel when the UE is in idle mode or in connected

mode, that is, in CELL_FACH, CELL_PCH, or URA_PCH state.

l The UE may use the scheduling information in MIB and SB to locate each SIB to be acquired. If the

UE receives a SIB in a position according to the scheduling information and consider the content

valid, it will read and store it.




Contents

1. PLMN Selection




5. Paging Procedure

6. Access Procedure




Cell Selection

l When the PLMN is selected and the UE is in idle mode, the UE

starts to select a cell to camp on and to obtain services.

l There are four states involved in cell selection:

p Camped normally

p Any cell selection

p Camped on any cell

p Connected mode

l Camped normally: The cell that UE camps on is called the suitable cell. In this state, the UE obtains

normal service.

l Any cell selection: In this state, the UE shall attempt to find an acceptable cell of an any PLMN to

camp on, trying all RATs that are supported by the UE and searching first for a high quality cell

l Camped on any cell: The cell that UE camps on is called the acceptable cell. In this state the UE

obtains limited service. The UE shall regularly attempt to find a suitable cell of the selected PLMN,

trying all RATs that are supported by the UE.

l Connected mode: When returning to idle mode, the UE shall use the procedure Cell selection when

leaving connected mode in order to find a suitable cell to camp on and enter state Camped

normally. If no suitable cell is found in cell reselection evaluation process, the UE enters the state

Any cell selection.




Cell Selection (Cont.)

l Two types of cell selection:

p Initial cell selection

n If no cell information is stored for the PLMN, the UE starts this procedure.

p Stored information cell selection

n If cell information is stored for the PLMN, the UE starts this procedure.

l Initial cell selection: If no cell information is stored for the PLMN, the UE starts the initial cell

selection. For this procedure, the UE need not know in advance which Radio Frequency (RF)

channels are UTRA bearers. The UE scans all RF channels in the UTRA band according to its

capabilities to find a suitable cell of the selected PLMN. On each carrier, the UE need only search for

the strongest cell. Once a suitable cell is found, this cell shall be selected.

l Stored information cell selection: For this procedure, the UE need know the central frequency

information and other optional cell parameters that are obtained from the measurement control

information received before, such as scrambling codes. After this procedure is started, the UE

selects a suitable cell if it finds one. Otherwise, the "Initial cell selection" procedure is triggered.




Cell Selection Criteria

minqualqualmeasqual QQS −=

oncompensatirxlevrxlevmeasrxlev PQQS −−= min

l Criterion S is used by the UE to judge whether the cell is

suitable to camped on.

l Criterion S : Srxlev > 0 & Squal > 0, where:

l If the pilot strength and quality of one cell meet S criteria, UE will stay in this cell and get other

system information. Then, UE will initiate a location update registration process.

l If the cell doesn’t satisfy S criteria, UE will get adjacent cells information from SIB11. Then, UE will

judge weather these cells satisfy S criteria. If the adjacent cell is suitable, UE will stay in the adjacent

cell.

l If no cell satisfies S criteria, UE will take the area as dead zone and continue the PLMN selection and

reselection procedure.

Max（UE_TXPWR_MAX_RACH-P_MAX，0）, dBmPcompensation

Maximum TX power level an UE may use when accessing the cell on RACH

(read in system information) (dBm)

UE_TXPWR_M

AX_RACH

Maximum RF output power of the UE (dBm)P_MAX

Minimum required RX level in the cell (dBm)Qrxlevmin

Minimum required quality level in the cell (dB)Qqualmin

Measured cell RX level value. This is received signal, CPICH RSCP for current

cells (dBm)

Qrxlevmeas

Measured cell quality value. The quality of the received signal expressed in

CPICH Ec/N0 (dB) for current cell

Qqualmeas

Cell RX level value (dBm)Srxlev

Cell quality value (dB)Squal

ExplanationParameters




Parameters of S Criterion

l QUALMEAS

p Parameter name: Cell Se-reselection quality measure

p Recommended value: CPICH_ECNO

l QQUALMIN

p Parameter name: Min quality level

p Recommended value: -18, namely -18dB

l QUALMEAS

p Parameter name: Cell Sel-reselection quality measure

p Value range: CPICH_ECNO(CPICH Ec/N0),CPICH_RSCP(CPICH RSCP)

p Physical unit: None.

p Content: Cell selection and reselection quality measure, may be set to CPICH Ec/N0 or

CPICH RSCP.

p Recommended value: CPICH_ECNO.

l QQUALMIN

p Parameter name: Min quality level

p Value range: -24~0

p Physical value range: -24~0; step: 1

p Physical unit: dB

p Content: The minimum required quality level corresponding to CPICH Ec/No. The UE can

camp on the cell only when the measured CPICH Ec/No is greater than the value of this

parameter.

p Recommended value: -18

p Set this parameter through ADD CELLSELRESEL, query it through LST CELLSELRESEL, and

modify it through MOD CELLSELRESEL.




Parameters of S Criterion

l QRXLEVMIN

p Parameter name: Min Rx level

p Recommended value: -58, namely -115dBm

l MAXALLOWEDULTXPOWER

p Parameter name: Max allowed UE UL TX power

p Recommended value: 21, namely 21dBm

l QRXLEVMIN

p Parameter name: Min Rx level

p Value range: -58~-13.

p Physical value range: -115~-25; step: 2 (-58:-115; -57:-113; ..., -13:-25 ).

p Physical unit: dBm.

p Content: The minimum required RX level corresponding to CPICH RSCP. The UE can camp

on the cell only when the measured CPICH RSCP is greater than the value of this parameter.

p Recommended value: -58.



l MAXALLOWEDULTXPOWER

p Parameter name: Max allowed UE UL TX power

p Value range: -50~33

p Physical value range: -50~33; step: 1

p Physical unit: dBm

p Content: The maximum allowed uplink transmit power of a UE in the cell, which is related

to the network planning. Content: Allowed maximum power transmitted on RACH in the

cell. It is related to network planning.

p Recommended value: 21






Cell Reselection

l After selecting a cell and camping on it, the UE periodically

searches for a better cell according to the cell reselection

criteria. If finding such a cell, the UE selects this cell to camp on.

l UE should monitor the quality of current cell and neighbor cells in order to camp on the better cell

to initiate service. The better cell is the most suitable one for the UE to camp on and obtain services.

The QoS of this cell is not necessarily more satisfying.




Measurement Start Criteria (Cont.)

l Intra-frequency measurement

Squal ≤ Sintrasearch

↓

Qqualmeas − Qqualmin ≤ Sintrasearch

↓

Qqualmeas ≤ Qqualmin + Sintrasearch

l Parameters of the measurement start criteria

Minimum required quality level in the cell (dB) .Qqualmin

Measurement threshold for UE to trigger inter-RAT cell reselection, compared with Squal.

SsearchRATm

Measurement threshold for UE to trigger inter-frequency cell reselection, compared with Squal.

Sintersearch

Measurement threshold for UE to trigger intra-frequency cell reselection, compared with Squal.

Sintrasearch


DescriptionName





l Inter-frequency measurement

Squal ≤ Sintersearch

↓

Qqualmeas − Qqualmin ≤ Sintersearch

↓

Qqualmeas ≤ Qqualmin + Sintersearch




SsearchRATm


Sintersearch


Sintrasearch


DescriptionName





l Inter-RAT measurement

Squal ≤ SsearchRATm

↓

Qqualmeas − Qqualmin ≤ SsearchRATm

↓

Qqualmeas ≤ Qqualmin + SsearchRATm




SsearchRATm


Sintersearch


Sintrasearch


DescriptionName




Parameters of Measurement Start Criteria

l IDLESINTRASEARCH

p Parameter name: Intra-freq cell reselection threshold for idle mode

p Recommended value: None

l CONNSINTRASEARCH

p Parameter name: Intra-freq cell reselection threshold for

connected mode


l IDLESINTRASEARCH

p Parameter name: Intra-freq cell reselection threshold for idle mode

p Value range: {{-16~10},{127}} .

p Physical value range: -32~20; step: 2.

p Physical unit: dB.

p Content: A threshold for intra-frequency cell reselection in idle mode. When the quality

(CPICH Ec/No measured by UE) of the serving cell is lower than this threshold plus the

[Qqualmin] of the cell, the intra-frequency cell reselection procedure will be started.

p Recommended value: None.



l CONNSINTRASEARCH

p Parameter name: Intra-freq cell reselection threshold for connected mode

p Value range: {{-16~10},{127}} .


p Physical unit: dB

p Content: A threshold for intra-frequency cell reselection in connect mode. When the quality


[Qqualmin] of the cell, the intra-frequency cell reselection procedure will be started.








l IDLESINTERSEARCH

p Parameter name: Inter-freq cell reselection threshold for idle mode


l CONNSINTERSEARCH

p Parameter name: Inter-freq cell reselection threshold for

connected mode


l IDLESINTERSEARCH

p Parameter name: Inter-freq cell reselection threshold for idle mode

p Value range: {{-16~10},{127}} .



p Content: A threshold for inter-frequency cell reselection in idle mode. When the quality


[Qqualmin] of the cell, the inter-frequency cell reselection procedure will be started.




l CONNSINTERSEARCH

p Parameter name: Inter-freq cell reselection threshold for connected mode

p Value range: {{-16~10},{127}} .


p Physical unit: dB

p Content: A threshold for inter-frequency cell reselection in connect mode. When the quality


[Qqualmin] of the cell, the inter-frequency cell reselection procedure will be started.








l SSEARCHRAT

p Parameter name: Inter-RAT cell reselection threshold


l SSEARCHRAT

p Parameter name: Inter-RAT cell reselection threshold

p Value range: {{-16~10},{127}} .



p Content: A threshold for inter-RAT cell reselection. When the quality (CPICH Ec/No

measured by UE) of the serving cell is lower than this threshold plus the [Qqualmin] of the

cell, the inter-RAT cell reselection procedure will be started.







Measurement Start Criteria Description

l The intra-frequency, inter-frequency, and inter-RAT measurement criteria are as shown in the figure.

l Usually, Sintrasearch > Sintersearch > SsearchRATm




Cell Reselection Criteria

l Criterion R is used for intra-frequency, inter-frequency cells and

inter-RAT cell reselection.

l The cell-ranking criterion R is defined by :

nsoffsetnmeasn QQR,, −=

hystssmeass QQR += ,

l The cells are ranked according to R criteria specified above ,deriving QQmeas,nmeas,n and QQmeas,smeas,s and

calculating R value.

l In Rs, s means serving cell. In Rn, n means neighbor cell.

l The offset Qoffset1s,n is used for Qoffsets,n to calculate Rn. The hysteresis Qhyst1s is used for

Qhysts to calculate Rs.

l If a TDD or GSM cell is ranked as the best cell, the UE shall reselect that TDD or GSM cell.

l If an FDD cell is ranked as the best cell and the quality measure for cell selection and reselection is

set to CPICH RSCP, the UE shall reselect that FDD cell.

l If an FDD cell is ranked as the best cell and the quality measure for cell selection and reselection is

set to CPICH Ec/N0, the UE shall perform a second ranking of the FDD cells according to the R

criteria specified above.

In this case, however, the UE uses the measurement quantity CPICH Ec/N0 for deriving the Qmeas,n

and Qmeas,s and then calculating the R values of the FDD cells. The offset Qoffset2s,n is used for

Qoffsets,n to calculate Rn, the hysteresis Qhyst2s is used for Qhysts to calculate Rs.




Hysteresis and Time Interval

TimeTreselection

Quality

Rn

Rs

Qmeas,n

Qmeas,s

Qhyst,s

Qoffsets,n

l In all the previous cases, the UE can reselect a new cell only when the following conditions are met:

p The new cell is better ranked than the serving cell during a time interval Treselection.

p More than one second has elapsed since the UE camped on the current serving cell.




Parameters of R Criteria

l IDLEQHYST1S

p Parameter name: Hysteresis 1 for idle mode

p Recommended value: 2, namely 4dB

l CONNQHYST1S

p Parameter name: Hysteresis 1 for connect mode

p Recommended value: 2, namely 4dB

l IDLEQHYST1S


p Value range: 0~20.

p Physical value range: 0~40; step: 2.


p Content: The hysteresis value in idle mode for serving FDD cells in case the quality

measurement for cell selection and reselection is set to CPICH RSCP. It is related to the slow

fading feature of the area where the cell is located. The greater the slow fading variance is,

the greater this parameter.

p Recommended value: 2.



l CONNQHYST1S

p Parameter name: Hysteresis 1 for connected mode




p Content: The hysteresis value in connect mode for serving FDD cells in case the quality

measurement for cell selection and reselection is set to CPICH RSCP. It is related to the slow

fading feature of the area where the cell is located. The greater the slow fading variance is,

the greater this parameter.







Parameters of R Criteria (Cont.)

l IDLEQHYST2S


p Recommended value: Qhyst1s for idle mode

l CONNQHYST2S


p Recommended value: Qhyst1s for connected mode.

l IDLEQHYST2S


p Value range: {{0~20},{255}} .



p Content: The hysteresis value in idle mode for serving FDD cells in case the quality measurement for

cell selection and reselection is set to CPICH Ec/No. It is related to the slow fading feature of the area

where the cell is located. The greater the slow fading variance is, the greater this parameter. It is

optional. If it is not configured, [Hysteresis 1] will be adopted as the value.

p Recommended value: Qhyst1s for idle mode .

p Set this parameter through ADD CELLSELRESEL, query it through LST CELLSELRESEL, and modify it

through MOD CELLSELRESEL.

l CONNQHYST2S


p Value range: {{0~20},{255}} .



p Content: The hysteresis value in connect mode for serving FDD cells in case the quality measurement

for cell selection and reselection is set to CPICH Ec/No. It is related to the slow fading feature of the

area where the cell is located. The greater the slow fading variance is, the greater this parameter.

p Recommended value: Qhyst1s for connected mode. .

p Set this parameter through ADD CELLSELRESEL, query it through LST CELLSELRESEL, and modify it

through MOD CELLSELRESEL.





l TRESELECTIONS

p Parameter name: Reselection delay time

p Recommended value: 1, namely 1s.

l TRESELECTIONS

p Parameter name: Reselection delay time

p Value range: 0~31 .


p Physical unit: s.

p Content: If the signal quality of a neighboring cell is better than the serving cell during the

specified time of this parameter, the UE will reselect the neighboring cell. It is used to avoid

ping-pong reselection between different cells. Note: The value 0 corresponds to the default

value defined in the protocol.








l IDLEQOFFSET1SN

p Parameter name: IdleQoffset1sn

p Recommended value: 0, namely 0dB.

l CONNQOFFSET1SN

p Parameter name: ConnQoffset1sn


l IDLEQOFFSET1SN


p Offset of cell CPICH RSCP measurement value in cell selection or reselection when the UE is in idle

mode

p Value range: -50 to +50 .

p Physical value range: -50 to +50; step: 1.


p Content: This parameter is used for moving the border of a cell. The larger the value of this

parameter, the lower the probability of neighboring cell selection.


p Set this parameter through ADD INTRAFREQNCELL / ADD INTERFREQNCELL, query it through LST

INTRAFREQNCELL / LST INTERFREQNCELL, and modify it through MOD INTRAFREQNCELL / MOD

INTERFREQNCELL.

l CONNQOFFSET1SN


p Offset of cell CPICH RSCP measurement value in cell selection or reselection when the UE is in

connected mode


p Physical value range: -50 to +50 ; step: 1.







INTERFREQNCELL.





l IDLEQOFFSET2SN



l CONNQOFFSET2SN



l IDLEQOFFSET2SN


p Offset of cell CPICH Ec/No measurement value in cell selection or reselection when the UE is in idle

mode


p Physical value range: -50 to +50; step: 1.







INTERFREQNCELL.

l CONNQOFFSET2SN


p Offset of cell CPICH Ec/No measurement value in cell selection or reselection when the UE is in

connected mode


p Physical value range: -50 to +50 ; step: 1.







INTERFREQNCELL.




Contents

1. PLMN Selection




5. Paging Procedure

6. Access Procedure




Location Registration

l The location registration includes:

p Location update (for non-GPRS)

p Route update (for GPRS)

l The location registration is used for the PLMN to trace the current status of the UE and to ensure

that the UE is connected with the network when the UE does not perform any operation for a long

period.




Periodic Location Registration

l Periodic location registration is controlled by a Periodic

Location Update timer (T3212) or a Periodic Routing Area

Update timer (T3312)

l Periodic location registration may be used to periodically notify the network of the availability of the

UE.

l T3212 is for non-GPRS operation

l T3312 is for GPRS operation




Parameters of Location Registration

l T3212

p Parameter name: Periodical location update timer [6min]

p Recommended value: 10, namely 60min

l ATT

p Parameter name: Attach/detach indication

p Recommended value: ALLOWED

l T3212

p Parameter name: Periodical location update timer [6min]


p Physical unit: 6 min.

p Content: This parameter indicates the time length of the periodical location update.

Periodical location update is implemented by MS through the location update procedure. 0:

The periodical update procedure is not used. This parameter is valid only when [CN domain

ID] is set as CS_DOMAIN.


p Set this parameter through ADD CNDOMAIN, query it through LST CNDOMAIN, modify it

through MOD CNDOMAIN.

l ATT

p Parameter name: Attach/detach indication

p Value range: NOT_ALLOWED, ALLOWED .

p Content: NOT_ALLOWED indicates that MS cannot apply the IMSI attach/detach procedure.

ALLOWED indicates that MS can apply the IMSI attach/detach procedure. This parameter is

valid only when [CN domain ID] is set as CS_DOMAIN.

p Recommended value: ALLOWED.

p Set this parameter through ADD CNDOMAIN, query it through LST CNDOMAIN, modify it

through MOD CNDOMAIN.




Contents

1. PLMN Selection




5. Paging Procedure

6. Access Procedure




Paging Initiation

l CN initiated paging

l Establish a signaling connection

l UTRAN initiated paging

l Trigger the cell update procedure

l Trigger reading of updated system information

l For CN originated paging:

p In order to request UTRAN connect to UE, CN initiates the paging procedure, transmits

paging message to the UTRAN through Iu interface, and UTRAN transmits the paging

message from CN to UE through the paging procedure on Uu interface, which will make

the UE initiate a signaling connection setup process with the CN.

l For UTRAN originated paging:

p When the cell system message is updated: When system messages change, the UTRAN will

trigger paging process in order to inform UE in the idle, CELL_PCH or URA_PCH state to

carry out the system message update, so that the UE can read the updated system message.

p UE state transition: In order to trigger UE in the CELL_PCH or URA_PCH state to carry out

state transition (for example, transition to the CELL_FACH state), the UTRAN will perform a

paging process. Meanwhile, the UE will initiate a cell update or URA update process, as a

reply to the paging.




Paging Type 1l If UE is in CELL_PCH,URA_PCH or IDLE state，the paging

message will be transmitted on PCCH with paging type 1CN RNC1 RNC2 NODEB1.1 NODEB2.1 UE

RANAPRANAP

RANAP RANAP

PCCH: PAGING TYPE 1

PAGING

PAGING

PCCH: PAGING TYPE 1

l Paging type 1:

p The message is transmitted in one LA or RA according to LAI or RAI.

p After calculating the paging time, the paging message will be transmitted at that time

p If UE is in CELL_PCH or URA_PCH state, the UTRAN transmits the paging information in

PAGING TYPE 1 message to UE. After received paging message, UE performs a cell update

procedure to transit state to CELL_FACH.

l As shown in the above figure, the CN initiates paging in a location area (LA), which is covered by

two RNCs. After receiving a paging message, the RNC searches all the cells corresponding to the LAI,

and then calculates the paging time, at which it will send the PAGING TYPE 1 message to these cells

through the PCCH.




Paging Type 2l If UE is in CELL_DCH or CELL_FACH state，the paging message

will be transmitted on DCCH with paging type 2CN SRNC UE

RANAPRANAP

PAGING

RRCRRCDCCH: PAGING TYPE 2

l Paging type 2:

p If UE is in CELL_DCH or CELL_FACH state，the paging message will be transmitted on

DCCH with paging type 2

p The message will be only transmitted in a cell

l As shown in the above figure, if the UE is in the CELL_DCH or CELL_FACH state, the UTRAN will

immediately transmit PAGING TYPE 2 message to the paged UE on DCCH channel.




DRX Procedure

l UE receives the paging indicator on PICH periodically, that is

the Discontinuous Reception (DRX)

l The value for the DRX paging cycle length is determined as

follows: :

DRX Cycle Length ＝ (2^K)×PBP frames

l In idle mode, the UE can monitor the paging in two modes: one is to decode SCCPCH directly every

10ms, the other is to decode the PICH periodically. The second one is the DRX, which is

Discontinuous Reception Mechanism.

l The paging period formula:

p DRX Cycle Length ＝ (2^K)*PBP frames

p K is the “CN domain specific DRX cycle length coefficient”, which is broadcasted in SIB1.

The typical value is 6.

p PBP is paging block period, which is 1 for FDD mode

p The paging period should be 640ms if K is 6




DRX Procedure (Cont.)

l Through DRX, UE only listens to PICH at certain predefined time.

And UE will read the paging information on SCCPCH if the

paging indicator is 1.

l The value of the Paging Occasion is determined as follows:

Paging Occasion (CELL SFN) =

{(IMSI mod M) mod (DRX cycle length div PBP)} * PBP

+ n * DRX cycle length + Frame Offset

l Paging SFN formula:

p Paging Occasion (CELL SFN) = {(IMSI mod M) mod (DRX cycle length div PBP)} *PBP + n

*DRX cycle length + Frame Offset

p n =0, 1, 2……and the requirement is the calculated CELL SFN must be below its maximum

value 4096

p Frame Offset is 0 for FDD mode

p M is the number of SCCPCH which carries PCH, and the typical value is 1

p The formula cloud be simplified as: SFN = IMSI mod (2^K) + n * (2^K)





( )( )( ) NpNpSFNSFNSFNSFNPIq mod144

144mod512/64/8/18

×+++×+=

l UE must calculate q to know which PI to monitor in one frame

of PICH

l The q value is achieved by the following formula :

l Where, PI = (IMSI div 8192) mod NP

l SFN is the paging occasion of the UEl As shown in the followed figure, the UE needs to monitor the frames (paging occasions) indicated

by the red dots, and then decodes the qth PI of this frame.

。。。

0

2^K-1

0 4095

。。。

P I P I P I P I。。。。。。

0 1 q NP-1

One DRX cycle





τPICH

Associated S-CCPCH frame

PICH frame containing paging indicator

l Time offset between PICH and S-CCPCH

l The timing relationship between PICH and S-CCPCH is defined by the above figure, and the interval is 3 slots duration (2ms, 7680 chips).




Parameters of DRX

l DRXCYCLELENCOEF

p Parameter name: DRX cycle length coefficient


l PICHMODE

p Parameter name: PICH mode

p Recommended value: V36.

l DRXCYCLELENCOEF

p Parameter name: DRX cycle length coefficient


p Content: This parameter is broadcasted on SIB1. This parameter is used when a UE is in idle

mode.


p Set this parameter through ADD CNDOMAIN, query it through LST CNDOMAIN, and

modify it through MOD CNDOMAIN.

l PICHMODE

p Parameter name: PICH mode

p Value range: V18, V36, V72, V144 .

p Physical value range: 18, 36, 72, 144 .

p Content: Indicating the number of PIs contained in each frame on the PICH.

p Recommended value: V36 .

p Set this parameter through ADD PICH, query it through LST PICH.




Parameters of DRX

l MACCPAGEREPEAT

p Parameter name: Number of page re-TX


l MACCPAGEREPEAT

p Parameter name: Number of page re-TX

p Number of retransmissions of paging message


p Content: If the number of retransmissions of paging message exceeds this parameter value,

retransmissions stop.


p Set this parameter through SET DPUCFGDATA, query it through LST DPUCFGDATA.




Contents

1. PLMN Selection




5. Paging Procedure

6. Access Procedure




Two Working Modes of UE

l Idle mode (has no RRC connection with RNC)

p After turning on and location registration, UE will stay in idle mode

l Connected mode (has RRC connection with RNC)

p UE will switch to connected mode which could be CELL_FACH

state or CELL_DCH state from the idle mode

p After releasing RRC connection, UE will switch to the idle mode

from the connected mode

l By random access UE can switch to connected mode from idle

mode.

l The most important difference between idle mode and connected mode is whether UE has RRC

connection with UTRAN or not.

l Normally UE without service is in idle mode. If UE wants to access the network for service, RRC

connection should be setup at first which means UE will switch to connected mode. Random access

procedure must be performed for RRC connections setup.




Random Access Procedure

l Definition

p Random access procedure is initiated by UE in order to get service

from the system. Meanwhile, the access channels are allocated to

the UE by system

l This process may happen in the following scenarios:

p Attach and detach

p LA update and RA update

p Signaling connection for services




Random Access Channel

AICH accessslots

10 ms

#0 #1 #2 #3 #14#13#12#11#10#9#8#7#6#5#4τp-a

#0 #1 #2 #3 #14#13#12#11#10#9#8#7#6#5#4

PRACHaccess slots

SFN mod 2 = 0 SFN mod 2 = 1

10 ms

Access slot set 1 Access slot set 2

l Definition

l UE will transmit the preamble at the access time slot

l Each 20ms access frame is composed of two 10ms radio frames, which is divided into 15 access

time slot, and 5120 chips for each slot

l The PRACH access slots, AICH access slots and their time offset are showed in the above figure




RACH Sub-Channels

1413121110987

210765436

1413121110985

543210764

8141312111093

765432102

1110981413121

765432100

11109876543210

Random access sub-channels numberSFN mod 8

l The access slots of different RACH sub-channels are illustrated by the following table

l A RACH sub-channel defines a sub-set of the total set of uplink access slots. There are a total of 12

RACH sub-channels.




Access Service Class

l The PRACH resources can be classified into several ASCs, so as

to provide RACH applications with different priorities.

l For Frequency Division Duplex (FDD) mode, the PRACH resources include access timeslots and

preamble signatures, which can be classified into several ASCs, so as to provide RACH applications

with different priorities.

l The ASCs range from 0 to 7, and the quantity of ASCs is 8. "0" indicates the highest priority and "7"

indicates the lowest priority.

l The system will assign random access sub-channels and signatures according to the ASC (Access

Service Class ) of UE.

l Set ASC of PRACH through ADD PRACHASC, modify it through MOD PRACHASC, and remove it

through RMV PRACHASC.




Access Control

l “Access Control” is used by network operators to prevent

overload of radio access channels under critical conditions.

p Access class 0~Access Class 9

p Access class 11~Access Class 15

p Access class 10

l The access class number is stored in the SIM/USIM.

l Access class 0~9 are allocated to all the users. And the 10 classes show the same priority.

l Access class 11~15 are allocated to specific high priority users as follows. (The enumeration is not

meant as a priority sequence):

p Access class 15: PLMN staff

p Access class 14: users subscribing to emergency services

p Access class 13: public organizations

p Access class 12: users subscribing to security services

p Access class 11: users responsible for PLMN management

l Access Class 10 indicates whether or not network access for Emergency Calls is allowed for UEs

with access classes 0 to 9 or without an IMSI. For UEs with access classes 11 to 15, Emergency Calls

are not allowed if both "Access class 10" and the relevant Access Class (11 to 15) are barred.

Otherwise, Emergency Calls are allowed.




Mapping between AC and ASC

l The AC-ASC mapping information is optional and used for the

System Information Block 5 (SIB5) only.

l Set the mapping between AC and ASC through ADD PRACHACTOASCMAP, modify it through MOD

PRACHACTOASCMAP, and remove it through RMV PRACHACTOASCMAP.



START

Choose a RACH sub channel fromavailable ones

Get available signatures

Set Preamble Retrans Max

Set Preamble_Initial_Power

Send a preamble

Check the corresponding AI

Increase message part power by p-m based on preamble power

Set physical status to be RACHmessage transmitted Set physical status to be Nack

on AICH received

Choose a access slot again

Counter> 0 & PreamblePower-maximum allowed power

<6 dB

Choose a signature and increase preamble transmit power

Set physical status to be Nackon AICH received

Get negative AI

No AI

Report the physical status to MAC

END

Get positive AI

The counter of preamble retransmit Subtract-1, Commanded preamble

power increased by Power Ramp Step

N

Y

Send the corresponding message part

Random Access Procedure



l Physical random access procedure

p 1. Derive the available uplink access slots, in the next full access slot set, for the set of

available RACH sub-channels within the given ASC. Randomly select one access slot among

the ones previously determined. If there is no access slot available in the selected set,

randomly select one uplink access slot corresponding to the set of available RACH sub-

channels within the given ASC from the next access slot set. The random function shall be

such that each of the allowed selections is chosen with equal probability

p 2. Randomly select a signature from the set of available signatures within the given ASC

p 3. Set the Preamble Retransmission Counter to Preamble_ Retrans_ Max

p 4. Set the parameter Commanded Preamble Power to Preamble_Initial_Power

p 5. Transmit a preamble using the selected uplink access slot, signature, and preamble

transmission power

p 6. If no positive or negative acquisition indicator (AI ≠ +1 nor –1) corresponding to the

selected signature is detected in the downlink access slot corresponding to the selected

uplink access slot:

n A: Select the next available access slot in the set of available RACH sub-channels

within the given ASC

n B: select a signature

n C: Increase the Commanded Preamble Power

n D: Decrease the Preamble Retransmission Counter by one. If the Preamble

Retransmission Counter > 0 then repeat from step 6. Otherwise exit the physical

random access procedure

p 7. If a negative acquisition indicator corresponding to the selected signature is detected in

the downlink access slot corresponding to the selected uplink access slot, exit the physical

random access procedure Signature

p 8. If a positive acquisition indicator corresponding to the selected signature is detected ,

Transmit the random access message three or four uplink access slots after the uplink

access slot of the last transmitted preamble

p 9. Exit the physical random access procedure




RRC Connection Setup Procedure

l After random access RRC connection will be setup between

RNC and UE. UE will trigger the procedure of RRC connection

setup as following:

UEUE RNCRNC

RRC connection requestRRC connection request

RRC connection setupRRC connection setup

RRC connection setup completeRRC connection setup complete

l When a UE needs network service, it triggers RRC connection setup procedure as follows:

p The UE sends RRC CONNECTION REQUEST (in message part of PRACH) from the cell

where it camps. The cause of RRC connection is included in this message.

p The RNC allocates related resources for the UE and sends RRC CONNECTION SETUP to

the UE. RNC decides to set up RRC connection in dedicated channel (DCH) or common

channels (RACH in uplink and FACH in downlink) according to the cause of RRC connection.

p The UE sends RRC CONNECTION SETUP COMPLETE to the RNC. The RRC connection

setup ends.




UE Timers and Constants for RRC Connection Setup

l T300

p Parameter name: Timer 300 [ms]

p Recommended value: D2000, namely 2000ms

l N300

p Parameter name: Constant 300


l T300

p Parameter name: Timer 300[ms]

p Value range: D100, D200, D400, D600, D800, D1000, D1200, D1400, D1600, D1800,

D2000, D3000, D4000, D6000, D8000 .

p Physical value range: 100, 200, 400, 600, 800, 1000, 1200, 1400, 1600, 1800, 2000, 3000,

4000, 6000, 8000

p Physical unit: ms

p Content: T300 is started after the UE transmits the RRC CONNECTION REQUEST message

and stopped after the UE receives the RRC CONNECTION SETUP message. RRC

CONNECTION REQUEST resents upon the expiry of the timer if V300 less than or equal to

N300. Otherwise, the UE enters idle mode.

p Recommended value: D2000.

p Set this parameter through SET IDLEMODETIMER, query it through SET IDLEMODETIMER.

l N300

p Parameter name: Constant 300


p Content: Maximum number of retransmission of RRC CONNECTION REQUEST .


p Set this parameter through SET IDLEMODETIMER, query it through SET IDLEMODETIMER.




RRC Connection Establish Channel Type

l RRCCAUSE

p Parameter name: Cause of RRC connection establishment

p Recommended value: none

l SIGCHTYPE

p Parameter name: Channel type for RRC establishment

p Recommended value: none

l RRCCAUSE

p Parameter name: Cause of RRC connection establishment

p Value range: ORIGCONVCALLEST, ORIGSTREAMCALLEST, ORIGINTERCALLEST,

ORIGBKGCALLEST, ORIGSUBSTRAFFCALLEST, TERMCONVCALLEST, TERMSTREAMCALLEST,

TERMINTERCALLEST, TERMBKGCALLEST, EMERGCALLEST, INTERRATCELLRESELEST,

INTERRATCELLCHGORDEREST, REGISTEST, DETACHEST, ORIGHIGHPRIORSIGEST,

ORIGLOWPRIORSIGEST, CALLREEST, TERMHIGHPRIORSIGEST, TERMLOWPRIORSIGEST,

TERMCAUSEUNKNOWN, DEFAULTEST.

p Content: The cause of RRC connection establishment. .

p Recommended value: none.

p Set this parameter through SET RRCESTCAUSE, query it through LST RRCESTCAUSE.

l SIGCHTYPE

p Parameter name: Channel type for RRC establishment

p Value range: FACH, DCH_3.4K_SIGNALLING, DCH_13.6K_SIGNALLING.

p Content: FACH indicates that the RRC is established on the common channel.

DCH_3.4K_SIGNALLING indicates that the RRC is established on the dedicated channel of

3.4 kbit/s. DCH_13.6K_SIGNALLING indicates that the RRC is established on the dedicated

channel of 13.6 kbit/s. .

p Recommended value: none.

p Set this parameter through SET RRCESTCAUSE, query it through LST RRCESTCAUSE.



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