WCDMA RAN11 UE Behaviors in Idle Mode

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WCDMA UE Behaviors in Idle Mode

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N-2

Page2Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.

Foreword

UE behaviors in idle mode include:

PLMN selection

System information reception

Cell selection and reselection

Location registration

Paging procedure

Access procedure

PLMN selection

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

System information reception

The network broadcasts the network information to the UE that camps on the cell. Upon reception

of broadcast information, the UE obtains the network information and takes actions accordingly.

Cell selection and reselection

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

Location registration

This procedure is used by the UE to report its status to the network. This procedure is of two types:

periodical location registration and the location registration necessitated by changes in the location

area.

Paging procedure

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

URA_PCH state.

Access procedure

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

mode.

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References

3GPP TS 22.011: Service Accessibility

3GPP TS 23.122: NAS Functions Related to Mobile Station (MS) in

Idle Mode

3GPP TS 24.008: Mobile Radio Interface Layer 3 Specification; Core

Network Protocols - Stage 3

3GPP TS 25.304: UE Procedures in Idle Mode and Procedures for Cell

Reselection in Connected Mode

3GPP TS 25.331: Radio Resource Control (RRC)

3GPP TS 31.102: Characteristics of The USIM Application

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N-4


Objectives

Upon completion of this course, you will be able to:

Describe the working principles of the UE Behaviors in Idle Mode

feature

Perform parameters modification of the UE Behaviors in Idle Mode

feature

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N-5


Contents

1. PLMN Selection

2. System Information Reception

3. Cell Selection and Reselection

4. Location Registration

5. Paging Procedure

6. Access Procedure

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N-6


Contents

1. PLMN Selection




5. Paging Procedure

6. Access Procedure

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N-7


Cell Search

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

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 in UTRAN to find a suitable

cell in PLMN

Typical scenario of first occasion is the first time a new UE is put into use.

The second occasion is very common.

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N-8


Cell Search (Cont.)

Slot synchronization

Frame synchronization and code-group identification

Primary scrambling code identification

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.

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.

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.

If the UE has received information about which scrambling codes to search for, steps 2 and 3 above

can be simplified.

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N-9


PLMN Selection

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

selects a cell that belongs to another PLMN, then the UE selects the

registered PLMN or its equivalent PLMN

If no registered PLMN or equivalent PLMN is available, or if

registration fails, the UE performs one of the following two

procedures, depending on its operating mode:

Automatic PLMN selection: the UE automatically selects a PLMN according

to the priority order

Manual PLMN selection: the UE shows all available PLMNs to the

subscriber. The subscriber then selects a PLMN

The UE can get system information from PCCPCH, and the PLMN information is transmitted in MIB

of PCCPCH.

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

get SIB scheduling information from the MIB; if not, the UE will search another carrier, do this

procedure again.

The priority order of automatic PLMN selection mode:

The PLMN selected by the UE before automatic PLMN selection

Previously selected PLMN6

The PLMNs are arranged in the descending order of signal quality

Other PLMN/Access technology combinations excluding the previously selected PLMN

5

The PLMNs are arranged in priority order

Other PLMN/Access technology combinations with the high quality of received signals excluding the previously selected PLMN

4


PLMNs contained in the “Operator Controlled PLMN Selector with Access Technology” data filed in the SIM excluding the previously selected PLMN

3


PLMNs contained in the “User Controlled PLMN Selector with Access Technology” data filed in the SIM excluding the previously selected PLMN

2

Home PLMNsHPLMNs1

RemarkPLMN typesOrder

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N-10


PLMN Selection (Cont.)

Automatic PLMN selection: UE can select a PLMN from the Home

PLMNs (HPLMNs) and roam in the Visited PLMN (VPLMN)

Selecting from the HPLMNs: UE maintains a list of allowed and available

PLMNs in priority order. When selecting a PLMN, the UE searches for the

PLMNs from the highest priority to the lowest

Roaming in the VPLMN: UE periodically searches for the HPLMN and

higher priority PLMNs for better services

Manual PLMN selection: UE maintains a list of allowed and available

PLMNs in priority order. When selecting a PLMN, the UE indicates the

list to the subscriber who will select a PLMN, and then camps on the

selected PLMN

The MCC and MNC, which are in the PLMN identity of the HPLMN, match the MCC and MNC in the

IMSI of the UE.

Except the HPLMNs, the PLMNs that the UE camps on are defined as VPLMNs.

For the PLMN selection in the VPLMN, a value of T minutes may be stored in the SIM. Either T is in

the range 6 minutes to 8 hours with a step of 6 minutes or T indicates that no periodic attempts

shall be made. If no value is stored in the SIM, a default value of 60 minutes is used.

When the UE attempts to access the HPLMN or the PLMN with higher priority, the UE must adhere

to the following rules:

After the UE is switched on, a period of at least two minutes and at most T minutes shall

elapse before the first attempt is made.

Periodic attempts shall be performed only by the UE in idle mode.

Only the priority levels of equivalent PLMNs of the same country (which serve as the current

serving VPLMN) can be compared with the priority level of a selected PLMN.

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N-11


Contents

1. PLMN Selection




5. Paging Procedure

6. Access Procedure

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N-12


Structure of System Information

System information is organized as a tree, including:

MIB (Master Information Block)

SB (Scheduling Block)

SIB (System Information Block)

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.

MIB

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.

SB

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

SIB

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

information elements (IEs) with the same purpose.

Scheduling information for an SIB may only be included in either the MIB or one of the SB.

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

received an SIB in a position according to the scheduling information and considers the contents as

valid, UE will read and store the SIB.

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System Information

SIB1: contains the system information for NAS and the timer/counter

for UE

SIB2: contains the URA information

SIB3: contains the parameters for cell selection and cell re-selection

SIB5: contains parameters for the common physical channels of the

cell

SIB7: contains the uplink interference level and the refreshing timer

for SIB7

SIB11: contains measurement controlling information

SIB4: contains parameters for cell selection and cell re-selection while UE is in connected mode.

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

mode.

SIB8: contains the CPCH static information.

SIB9: contains the CPCH dynamic information.

SIB10: contains information to be used by UEs having their DCH controlled by a DRAC procedure.

Used in FDD mode only. To be used in CELL_DCH state only. Changes so often, its decoding is

controlled by a timer.

SIB12: contains measurement controlling information in connecting mode.

SIB13: contains ANSI-41 system information.

SIB14: contains the information in TDD mode.

SIB15: contains the position service information.

SIB16: contains the needed pre-configuration information for handover from other RAT to UTRAN.

SIB17: contains the configuration information for TDD.

SIB18: contains the PLMN identities of the neighboring cells.

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

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Reception of System Information

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

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N-15


Contents

1. PLMN Selection




5. Paging Procedure

6. Access Procedure

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N-16


Cell Selection

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

There are four states involved in cell selection:

Camped normally

Any cell selection

Camped on any cell

Connected mode

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

normal services.

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

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

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

obtains limited services. For example, UE may originate emergency call. The UE shall regularly

attempt to find a suitable cell of the selected PLMN, trying all RATs that are supported by the UE.

Connected mode: After RRC connection setup, the UE changes from the idle mode to the

connected mode (CELL_DCH, CELL_FACH, CELL_PCH, or URA_PCH state).

Cell selection of the UE leaving the connected mode:

When returning to the idle mode from the connected mode, the UE shall select a suitable

cell to camp on. Candidate cells for this selection are the cells used immediately before the

UE leaves the connected mode.

When returning to the idle mode after an emergency call on any PLMN, the UE shall select

an acceptable cell to camp on. Candidate cells for this selection are the cells used

immediately before the UE leaves the connected mode.

If no acceptable cell is found, the UE shall continue to search for an acceptable cell on any

PLMN in the state "Any cell selection".

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Cell Selection (Cont.)

Two types of cell selection:

Initial cell selection

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

Stored information of cell selection

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

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.

Stored information of cell selection: For this procedure, the UE has to 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 any. Otherwise, the "Initial cell selection" procedure is triggered.

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N-19


Cell Selection Criteria

minqualqualmeasqual QQS −=

oncompensatirxlevrxlevmeasrxlev PQQS −−= min

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

suitable to camped on

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

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.

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.

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) (dB)Pcompensation

MaxAllowedUlTxPower, Max allowed UE UL Tx Power (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 RX level of the received signal indicated

CPICH RSCP (dBm) for current cell

Qrxlevmeas

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

average CPICH Ec/No (dB) for current cell

Qqualmeas

Cell selection RX level value (dBm)Srxlev

Cell selection quality value (dB)Squal

DescriptionParameter

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N-20


Parameters of S Criterion

Qqualmin

Parameter name: Min quality level

Recommended value: -18, namely -18dB

Qrxlevmin

Parameter name: Min Rx level

Recommended value: -58, namely -115dBm

Qqualmin

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.

Value range: -24~0

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

Physical unit: dB

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

modify it through MOD CELLSELRESEL.

Qrelevmin

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.

Value range: -58~-13

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

Physical unit: dBm



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Parameters of S Criterion (Cont.)

MaxAllowedUlTxPower

Parameter name: Max allowed UE UL TX power

Recommended value: 24, namely 24dBm

MaxAllowedUlTxPower

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

to the network planning.

Value range: -50~33


Physical unit: dBm



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Cell Reselection

The signal strength of both serving cell and neighboring cells

varies with the movement of a UE and so the UE needs to

select the most suitable cell to camp on. This process is called

cell reselection

Cell reselection process:

Measurement start criteria

Cell reselection criteria

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N-23


Measurement Start Criteria

Intra-frequency measurement:

Squal ≤ Sintrasearch

↓

Qqualmeas − Qqualmin ≤ Sintrasearch

↓

Qqualmeas ≤ Qqualmin + Sintrasearch

If Squal > Sintrasearch, the UE need not start the intra-frequency measurement.

If Squal ≤ Sintrasearch, the UE need to start the intra-frequency measurement.

If system messages do not contain Sintrasearch, the UE always need to start the intra-frequency

measurement.

Parameters of the measurement start criteria:

Minimum required quality level in the cell (dB)Qqualmin

Measurement threshold for UE to trigger inter-RAT cell reselectionSsearchRATm

Measurement threshold for UE to trigger inter-frequency cell reselectionSintersearch

Measurement threshold for UE to trigger intra-frequency cell reselectionSintrasearch

Cell quality value (dB)Squal

DescriptionName

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Measurement Start Criteria (Cont.)

Inter-frequency measurement:

Squal ≤ Sintersearch

↓

Qqualmeas − Qqualmin ≤ Sintersearch

↓

Qqualmeas ≤ Qqualmin + Sintersearch

If Squal > Sintersearch, the UE need not start the inter-frequency measurement.

If Squal ≤ Sintersearch, the UE need to start the inter-frequency measurement.

If system messages do not contain Sintersearch, the UE always need to start the inter-frequency

measurement.

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Measurement Start Criteria (Cont.)

Inter-RAT measurement:

Squal ≤ SsearchRATm

↓

Qqualmeas − Qqualmin ≤ SsearchRATm

↓

Qqualmeas ≤ Qqualmin + SsearchRATm

If Squal > SsearchRATm, the UE need not start the inter-RAT measurement.

If Squal ≤ SsearchRATm, the UE need to start the inter-RAT measurement.

If system messages do not contain SsearchRATm, the UE always need to start the inter-RAT

measurement.

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Parameters of Measurement Start Criteria

IdleSintrasearch

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

Recommended value: 127, namely none

ConnSintrasearch

Parameter name: Intra-freq cell reselection threshold for

connected mode


IdleSintrasearch

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. This

parameter is not configured when its value is 127.

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


Physical unit: dB



ConnSintrasearch

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. This


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


Physical unit: dB



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N-27


Parameters of Measurement Start Criteria (Cont.)

IdleSintersearch

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


ConnSintersearch

Parameter name: Inter-freq cell reselection threshold for

connected mode


IdleSintersearch

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. This


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


Physical unit: dB



ConnSintersearch

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. This


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


Physical unit: dB



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Parameters of Measurement Start Criteria (Cont.)

SsearchRat

Parameter name: Inter-RAT cell reselection threshold


SearchRat

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. This parameter is not

configured when its value is 127.

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


Physical unit: dB



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Measurement Start Criteria Description

The intra-frequency, inter-frequency, and inter-RAT measurement criteria are as shown in the above

figure.

The intra-frequency cell reselection has a priority higher than the inter-frequency cell reselection and

inter-RAT cell reselection, the intra-frequency cell reselection start threshold should be higher than

the inter-frequency cell reselection start threshold and inter-RAT cell reselection start threshold.

If the cell reselection threshold is set to a comparatively high value, the UE may frequently start cell

reselections, and the battery of the UE may be largely consumed. If the cell reselection threshold is

set to a comparatively low value, it is difficult for cell reselections to be started, and the UE may not

timely reside in the cells with good quality, affecting the quality of communication between the

UTRAN and the UE. For detailed information, refer to 3GPP TS 25.304.

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N-30


Cell Reselection Criteria

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

inter-RAT cell reselection

The cell-ranking criterion R is defined by:

nsoffsetnmeasn QQR,, −=

hystssmeass QQR += ,

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

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

Qhysts to calculate Rs.

The UE shall rank the cells according to the R criterion, derive Qmeas,n and Qmeas,s and calculate

the R values, as described in the following cases:

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

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

reselection is set to CPICH RSCP (QualMeas = CPICH_RSCP), the UE shall reselect that FDD

cell.

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 (QualMeas = CPICH_ECNO), 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.

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Hysteresis and Time Interval

TimeTreselection

Quality

Rn

Rs

Qmeas,n

Qmeas,s

Qhyst,s

Qoffsets,n

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

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

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

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N-32


Parameters of R Criteria

QualMeas

Parameter name: Cell Sel-reselection quality measure

Recommended value: CPICH_ECNO

Treselections

Parameter name: Reselection delay time

Recommended value: 1, namely 1s

QualMeas

Content: Measurement quantity of cell selection and reselection. It can be set to CPICH

Ec/N0 or CPICH RSCP.

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

Physical value range: CPICH_ECNO, CPICH_RSCP

Physical unit: None



Treselections

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

during the specified time of this parameter, the UE reselects the neighboring cell. It is used

to avoid ping-pong reselection between different cells.

Value range: 0~31

Physical value range: 0~31; step: 1

Physical unit: s



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N-33


Parameters of R Criteria (Cont.)

IdleQhyst1s

Parameter name: Hysteresis 1 for idle mode

Recommended value: 2, namely 4dB

ConnQhyst1s

Parameter name: Hysteresis 1 for connected mode


IdleQhyst1s

Content: The hysteresis value of the serving FDD cells in idle mode 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.

Value range: 0~20


Physical unit: dB



ConnQhyst1s

Content: The hysteresis value of the serving FDD cells in connected mode 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 .

Value range: 0~20


Physical unit: dB



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N-34



IdleQhyst2s

Parameter name: Hysteresis 2 for idle mode


ConnQhyst2s

Parameter name: Hysteresis 2 for connected mode


IdleQhyst2s

Content: The hysteresis value of the serving FDD cells in idle mode 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.

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


Physical unit: dB

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

through MOD CELLSELRESEL.

ConnQhyst2s

Content: The hysteresis value of the serving FDD cells in connected mode 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.

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


Physical unit: dB

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

through MOD CELLSELRESEL.

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N-35



IdleQoffset1sn

Parameter name: IdleQoffset1sn


ConnQoffset1sn

Parameter name: ConnQoffset1sn


IdleQoffset1sn

Content: Offset of cell CPICH RSCP measurement value in cell selection or reselection when

the UE is in idle mode.

Value range: -50~+50

Physical value range: -50~+50; step: 1

Physical unit: dB

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

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

INTRAFREQNCELL / MOD INTERFREQNCELL.

ConnQoffset1sn

Content: Offset of cell CPICH RSCP measurement value in cell selection or reselection when

the UE is in connected mode.



Physical unit: dB




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IdleQoffset2sn

Parameter name: IdleQoffset2sn


ConnQoffset2sn

Parameter name: ConnQoffset2sn


IdleQoffset2sn

Content: Offset of cell CPICH Ec/No measurement value in cell selection or reselection when

the UE is in idle mode.



Physical unit: dB




ConnQoffset2sn

Content: Offset of cell CPICH Ec/No measurement value in cell selection or reselection when

the UE is in connected mode.



Physical unit: dB




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N-37


Contents

1. PLMN Selection




5. Paging Procedure

6. Access Procedure

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N-38


Location Registration

The location registration includes:

Location update (for non-GPRS)

Route update (for GPRS)

The types of location registration:

Normal location registration

Periodic location registration

IMSI attach/detach

Location registration is used for the PLMN to trace the current status of the UE. Location

registration ensures that the UE is connected to the network when the UE does not perform any

operation for a long period.

The UE performs normal location registration in the following conditions:

After being switched on, the UE selects a suitable cell that belongs to a new LA or RA. That

is, the LA or RA is different from that recorded in the USIM before the switch-off of the UE.

The UE in idle mode enters the cell of a new LA or RA.

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N-39


Periodic Location Registration

Periodic location registration is controlled by a Periodic

Location Update timer (T3212, for non-GPRS operation) or a

Periodic Routing Area Update timer (T3312, for GPRS operation)

T3212 is set through T3212 on the RNC side

T3312 is set on the CN side

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

UE.

The value of T3212 is sent by the network to the UE in SIB1. The value of T3312 is sent by the

network to the UE in the messages ATTACH ACCEPT and ROUTING AREA UPDATE ACCEPT. The

value of T3312 shall be unique within an RA.

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N-40


IMSI Attach/Detach

The IMSI attach/detach process facilitates the fast location

registration of the UE in specific conditions

IMSI attach/detach is set through ATT on the RNC side

If the UE still stays in the same LA or RA after being switched on again, the UE shall perform an LR

request indicating IMSI attach. Otherwise, the UE shall perform an LR request indicating normal

location update.

When the IMSI attach/detach operation applies, the UE shall send the IMSI detach message to the

network when the UE is switched off or the SIM is removed while being in the UPDATED state. This

IMSI detach message will not be acknowledged by the network.

The system information contains an indicator indicating whether the IMSI attach/detach operation is

mandatory in the cell. The UE shall operate in accordance with the received value of the indicator.

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N-41


Parameters of Location Registration

T3212

Parameter name: Periodical location update timer [6min]

Recommended value: 10, namely 60min

ATT

Parameter name: Attach/detach indication

Recommended value: ALLOWED

T3212

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.

Value range: 0~255


Physical unit: min

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

through MOD CNDOMAIN.

ATT

Content: Indicating whether attach/detach is allowed. 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.

Value range: NOT_ALLOWED, ALLOWED

Physical value range: NOT_ALLOWED, ALLOWED

Physical unit: None

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

through MOD CNDOMAIN.

Course Name


N-42


Contents

1. PLMN Selection




5. Paging Procedure

6. Access Procedure

Course Name


N-43


Paging Initiation

CN initiated paging:

Establish a signaling connection

UTRAN initiated paging:

Trigger the cell update procedure

Trigger reading of updated system information

For CN originated paging:

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.

For UTRAN originated paging:

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.

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.

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N-44


Paging Type 1If UE is in the idle or CELL/URA_PCH 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

Paging type 1:

The message is transmitted in one LA or RA for idle state, or in one cell for CELL_PCH state,

or in one URA for URA_PCH state.

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

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

or URA update procedure to transit state to CELL_FACH.

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.

Course Name


N-45


Paging Type 2If 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

Paging type 2:

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

DCCH with paging type 2.

The message will be only transmitted in a cell.

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.

Course Name


N-46


Typical Call Flow of UE UE NAS UE AS NSS MSC

paging

AUTHENTICATION REQ UEST

AUTHENTICATION RESPO NSE

RR_SECURITY_CONTRO L_REQ

(IK CK)

Security m ode contro l

SETUP

C ALL CONFIRM

ALERT

CONNECT

CONNECT ACKNO W LEDG E

R AB setup process

paging

RR_EST_REQ (PAG ING RESPO NSE)

RR_PAING_IND

IN ITIAL_DIRECT_TRAN SFER

(PAGING RESPO NSE)

R ANAPR ANAP

RR C setup process

Many problems will cause the target UE cannot receive the paging message properly:

Power setting of paging channel is unreasonable

Unreasonable paging strategies will result in paging channel congestion, which can cause

paging message loss

Paging parameter is unreasonable

Equipment fault

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N-47


DRX Procedure

To reduce power consumption, the UE can read the

information from the PICH only at a particular time. This is

known as the Discontinuous Reception (DRX) technology. The

interval between two consecutive periods of time is called DRX

cycle

The value for the DRX paging cycle length is determined as

follows:

DRX Cycle Length ＝ MAX (2k, PBP) frames

The DRX paging period formula:

DRX Cycle Length ＝ MAX(2k, PBP) frames

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

The typical value is 6.

PBP is Paging Block Periodicity , which is 1 for FDD mode.

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

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N-48


DRX Procedure (Cont.)

The value of the Paging Occasion is determined as follows:

Paging Occasion (CELL SFN) =

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

+ n * DRX cycle length + Frame Offset

Paging SFN formula:

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

cycle length + Frame Offset

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

value 4095.

Frame Offset is 0 for FDD mode.

K is the number of SCCPCH which carries PCH, and the typical value is 1.

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

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N-49



In FDD the UE shall monitor its paging indicator in the PICH

frame with SFN given by the Paging Occasion

The Paging Indicator to use is calculated by using the following

formula:

PI = (IMSI div 8192) mod NP

As shown in the below figure, the UE needs to monitor the frames (paging occasions) indicated by

the red dots, and then decodes the qth PI of this frame. (The qth PI is obtained based on the above

formula).

If the UE has no IMSI, for instance when making an emergency call without USIM, the UE shall use

as default numbers, IMSI = 0 and DRX cycle length = 256 (2.56 s), in the formulas above.

。。。

0

2^K-1

0 4095

。。。

P I P I P I P I。。。。。。

0 1 q NP-1

One DRX cycle

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N-50



τPICH

Associated S-CCPCH frame

PICH frame containing paging indicator

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

Time offset between PICH and SCCPCH:

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

Course Name


N-51


Parameters of DRX

DRXCyclelenCoef

Parameter name: DRX cycle length coefficient

Recommended value: 6

PICHMode

Parameter name: PICH mode

Recommend value: V36

DRXCyclelenCoef

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

mode.

Value range: 6~9

Physical value range: 6~9

Physical unit: None

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

modify it through MOD CNDOMAIN.

PICHMode

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

Value range: V18, V36, V72, V144

Physical value range: 18, 36, 72, 144

Physical unit: None

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

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N-52


Parameters of DRX (Cont.)

MaccPageRepeatTimes

Parameter name: Number of page re-TX


MaccPageRepeatTimes

Content: This parameter defines the times of retransmission of paging messages. If the

times of retransmission exceeds the value of this parameter, retransmission stops.

Value range: 0~2


Physical unit: None

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

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N-53


Contents

1. PLMN Selection




5. Paging Procedure

6. Access Procedure

Course Name


N-54


Two Working Modes of UE

Idle mode:

After turning on, UE will stay in idle mode

Connected mode:

UE will switch to connected mode which could be CELL_FACH

state or CELL_DCH state from the idle mode

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

from the connected mode

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

connection with UTRAN or not.

In idle mode, UE will be identified by IMSI, TMSI or PTMSI and so on.

In connected mode, UE will be identified by URNTI (UTRAN Radio Network Temporary Identity),

which is the ID of one RRC connection.

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N-55


Random Access Procedure

Definition:

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

This process may happen in the following typical scenarios:

Attach and detach

LA update and RA update

Signaling connection for services

Course Name


N-56


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

UE will transmit the preamble at the access time slot.

Access frame is composed of two 10ms radio frames, which is divided into 15 access time slot, and

5120 chips for each slot.

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

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N-57


RACH Sub-Channels

1413121110987

210765436

1413121110985

543210764

8141312111093

765432102

1110981413121

765432100

11109876543210

Random access sub-channels numberSFN mod 8

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

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.

Set Preamble signatures and RACH sub-channel no. through ADD PRACHBASIC, query them

through LST PRACH.

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N-58


Access Service Class

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

to provide RACH applications with different priorities

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.

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.

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

through RMV PRACHASC.

Course Name


N-59


Access Control

“Access Control” is used by network operators to prevent

overload of radio access channels under critical conditions

Access class 0 ~ Access Class 9

Access class 11 ~ Access Class 15

Access class 10

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

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

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

meant as a priority sequence):

Access class 15: PLMN staff

Access class 14: users subscribing to emergency services

Access class 13: public organizations

Access class 12: users subscribing to security services

Access class 11: users responsible for PLMN management

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.

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N-60


Mapping between AC and ASC

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

System Information Block 5 (SIB5) only

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

PRACHACTOASCMAP, and remove it through RMV PRACHACTOASCMAP.

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N-61

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

Change 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 & Commanded preamble power - 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 by 1, Commanded preamble power increased by Power Ramp Step

N

Y

Send the corresponding message part

Random Access Procedure

Course Name


N-62

Random access procedure

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.

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

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

4. Set the preamble transmission power and Commanded Preamble Power to

Preamble_Initial_Power.

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

transmission power.

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:

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

within the given ASC;

B: select a signature;

C: increase the preamble transmission power and Commanded Preamble Power by

Power Ramp Step, whereas the maximum value of preamble transmission power is

equal to MaxallowedUlTxPower.

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

Retransmission Counter > 0 and Commanded Preamble Power – maximum allowed

power < 6dB, then repeat from step 5. Otherwise exit the physical random access

procedure.

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.

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

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

access slot of the last transmitted preamble. After that, exit the physical random access

procedure.

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N-63


RRC Connection Message

Typical RRC connection messages:

RRC_CONNECTION_REQUEST

RRC_CONNECTION_SETUP

RRC_CONNECTION_SETUP_COMPLETE

RRC_CONNECTION_RELEASE

When a UE needs network service, it first sets up RRC connection as follows:

The UE sends a RRC CONNECTION REQUEST message from the cell where it camps to

the RNC.

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

message to the UE.

The UE sends a RRC CONNECTION SETUP COMPLETE message to the RNC. The RRC

connection setup ends.

Course Name


N-64


UE Timers and Constants in Idle Mode

T300

Parameter name: Timer 300 [ms]

Recommended value: D2000, namely 2s

N300

Parameter name: Constant 300


T300

Content: T300 is started when UE sends the RRC CONNECTION REQUEST message. It is

stopped when UE receives the RRC CONNECTION SETUP message. RRC CONNECTION

REQUEST will be resent upon the expiry of the timer if V300 is lower than or equal to

N300, else enter idle mode.

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

D2000, D3000, D4000, D6000, D8000

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

4000, 6000, 8000

Physical unit: ms

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

N300

Content: Maximum number of retransmissions of the RRC CONNECTION REQUEST

message.

Value range: 0~7


Physical unit: None


Course Name


N-65


UE Timers and Constants in Idle Mode (Cont.)

T312

Parameter name: Timer 312 [s]

Recommended value: 6, namely 6s

N312

Parameter name: Constant 312

Recommended value: D1, namely 1

T312

Content: T312 is started when UE starts to establish a DCH, and stopped when UE detects

consecutive N312 "in sync" indications from L1. It indicates physical channel setup failure

upon the expiry of the timer.

Value range: 1~15

Physical value range: 1~15s

Physical unit: s


N312

Content: Maximum number of successive "in sync" indications received from L1.

Value range: D1, D2, D4, D10, D20, D50, D100, D200, D400, D600, D800, D1000

Physical value range: 1, 2, 4, 10, 20, 50, 100, 200, 400, 600, 800, 1000

Physical unit: None


Course Name


N-66


RRC Connection Establish Channel Type and Bit Rate

RrcCause

Parameter name: Cause of RRC connection establishment

Recommended value: refer to next page

SigChType

Parameter name: Channel type for RRC establishment

Recommended value: refer to next page

RrcCause

Content: This parameter specifies the cause of RRC connection establishment, that is, the value of

the Establishment cause IE in the RRC CONNECTION REQUEST message.

Value range: ORIGCONVCALLEST, ORIGSTREAMCALLEST, ORIGINTERCALLEST, ORIGBKGCALLEST,

ORIGSUBSTRAFFCALLEST, TERMCONVCALLEST, TERMSTREAMCALLEST, TERMINTERCALLEST,

TERMBKGCALLEST, EMERGCALLEST, INTERRATCELLRESELEST, INTERRATCELLCHGORDEREST,

REGISTEST, DETACHEST, ORIGHIGHPRIORSIGEST, ORIGLOWPRIORSIGEST, CALLREEST,

TERMHIGHPRIORSIGEST, TERMLOWPRIORSIGEST, TERMCAUSEUNKNOWN, MBMSCALLEST,

DEFAULTEST

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

SigChType

Content: This parameter specifies the channel type and bit rate for RRC connection establishment.

Value range: FACH, DCH_3.4K_SIGNALLING, DCH_6.8K_SIGNALLING, DCH_13.6K_SIGNALLING,

DCH_27.2K_SIGNALLING

FACH: The RRC connection is set up on the common channel.

DCH_3.4K_SIGNALLING: The RRC connection is set up on the 3.4 kbit/s dedicated channel.

DCH_6.8K_SIGNALLING: The RRC connection is set up on the 6.8 kbit/s dedicated channel.

DCH_13.6K_SIGNALLING: The RRC connection is set up on the 13.6 kbit/s dedicated

channel.

DCH_27.2K_SIGNALLING: The RRC connection is set up on the 27.2 kbit/s dedicated

channel.

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

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N-67

OFFDCH_3.4K_SIGNALLINGDEFAULTEST

OFFDCH_3.4K_SIGNALLINGMBMSCALLEST

OFFFACHTERMCAUSEUNKNOWN

OFFFACHTERMLOWPRIORSIGEST

OFFDCH_13.6K_SIGNALLINGTERMHIGHPRIORSIGEST

OFFDCH_3.4K_SIGNALLINGCALLREEST

OFFFACHORIGLOWPRIORSIGEST

OFFDCH_13.6K_SIGNALLINGORIGHIGHPRIORSIGEST

OFFFACHDETACHEST

OFFDCH_13.6K_SIGNALLINGREGISTEST

OFFDCH_3.4K_SIGNALLINGINTERRATCELLCHGORDEREST

OFFDCH_3.4K_SIGNALLINGINTERRATCELLRESELEST

OFFDCH_13.6K_SIGNALLINGEMERGCALLEST

OFFDCH_13.6K_SIGNALLINGTERMBKGCALLEST

OFFDCH_13.6K_SIGNALLINGTERMINTERCALLEST

OFFDCH_13.6K_SIGNALLINGTERMSTREAMCALLEST

OFFDCH_13.6K_SIGNALLINGTERMCONVCALLEST

OFFDCH_13.6K_SIGNALLINGORIGSUBSTRAFFCALLEST

OFFDCH_13.6K_SIGNALLINGORIGBKGCALLEST

OFFDCH_13.6K_SIGNALLINGORIGINTERCALLEST

OFFDCH_13.6K_SIGNALLINGORIGSTREAMCALLEST

OFFDCH_13.6K_SIGNALLINGORIGCONVCALLEST

EFachSwitchSigChTypeRrcCause

Course Name


N-68

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Documents

WCDMA RAN11 UE Behaviors in Idle Mode