wcdma bsc6900 r11 features and algorithms

7/23/2019 WCDMA BSC6900 R11 Features and Algorithms

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WCDMA Radio Network Features &

Algorithms

Southern Eastern Africa Learning

Services

BSC6900 V9-R11


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WCDMA UE BEHAVIORS IN IDLE MODE ........................................................................................................ 3

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WCDMA UE BEHAVIORS IN IDLE MODE

Copyright 2009 Huawei Technologies Co., Ltd. All ri ghts reserved.

Foreword

UE behaviors in idle mode include:

PLMN selection

System information reception

Cell selection and reselection

Location registration

Paging procedure

Access procedure

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

System information receptionThe 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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Copyright 2009 Hua wei Technologies Co., Ltd. All ri ghts reserved.

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


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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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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Cell Search (Cont.)

Slot synchronization

Frame synchronization andcode-group identification

Primary scrambling codeidentification

Step 1: Slot synchronization

During the first step of the cell search procedure, the UE uses the primary synchronisationcode (PSC) to acquire slot synchronisation to a cell.

Step 2: Frame synchronization and code-group identificationDuring 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 thecell found in the first step.

Step 3: Primary scrambling code identificationDuring 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 identifiedthrough 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 3above can be simplified.


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Copyright 2009 Huawei Technologies Co., Ltd. All rights reserved.

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:


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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 minutesis used.

When the UE attempts to access the HPLMN or the PLMN with higher priority, the UE mustadhere to the following rules:

After the UE is switched on, a period of at least two minutes and at most T minutesshall 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 thecurrent serving VPLMN) can be compared with the priority level of a selected PLMN.


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

PLMN type, PLMN identity, reference and scheduling information for a number ofSIBs 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 ofsystem 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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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 UEobtains normal services.

Any cell selection: In this state, the UE shall attempt to find an acceptable cell of any PLMNto 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 shallregularly 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 asuitable 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 cellsused immediately before the UE leaves the connected mode.

If no acceptable cell is found, the UE shall continue to search for an acceptable cell onany PLMN in the state "Any cell selection".


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Copyright 2009 Huawei Technologies Co., Ltd. All r ights reserved.

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 needonly 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 centralfrequency information and other optional cell parameters that are obtained from the

measurement control information received before, such as scrambling codes. After thisprocedure is started, the UE selects a suitable cell if any. Otherwise, the "Initial cell selection"

procedure is triggered.


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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 doesnt 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 reselectionprocedure.


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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 UCELLSELRESEL, query it through LSTUCELLSELRESEL, and modify it through MOD UCELLSELRESEL.

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

Set this parameter through ADD UCELLSELRESEL, query it through LSTUCELLSELRESEL, and modify it through MOD UCELLSELRESEL.


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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 value range: -50~33; step: 1

Physical unit: dBm Set this parameter through ADD UCELLSELRESEL, query it through LST

UCELLSELRESEL, and modify it through MOD UCELLSELRESEL.


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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


Measurement Start Criteria

Intra-frequency measurement:

Squal Sintrasearch

Qqualmeas QqualminSintrasearch

QqualmeasQqualmin + Sintrasearch


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

If SqualSintrasearch, 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:


Measurement Start Criteria (Cont.)

Inter-frequency measurement:

Squal Sintersearch

Qqualmeas QqualminSintersearch

QqualmeasQqualmin + Sintersearch

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

If SqualSintersearch, 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 QqualminSsearchRATm

Qqualmeas Qqualmin + SsearchRATm

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

If SqualSsearchRATm, 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.


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


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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 value range: -32~20; step: 2 Physical unit: dB Set this parameter through ADD UCELLSELRESEL, query it through LST UCELLSELRESEL, and

modify it through MOD UCELLSELRESEL.

ConnSintrasearch Content: A threshold for intra-frequency cell reselection in connect 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 value range: -32~20; step: 2 Physical unit: dB Set this parameter through ADD UCELLSELRESEL, query it through LST UCELLSELRESEL, and


Copyrigh t 2009 H uawei Technologies Co., Ltd. All rights reserved.

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 (CPICH Ec/No

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

inter-frequency cell reselection procedure will be started. This parameter is not configured when its

value is 127. Value range: {{-16~10}, {127}} Physical value range: -32~20; step: 2 Physical unit: dB


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


ConnSintersearch Content: A threshold for inter-frequency cell reselection in connect 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 inter-frequency cell reselection procedure will be started. This parameter is not configured when itsvalue is 127.

Value range: {{-16~10}, {127}} Physical value range: -32~20; step: 2 Physical unit: dB Set this parameter through ADD UCELLSELRESEL, query it through LST UCELLSELRESEL, and



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 value range: -32~20; step: 2 Physical unit: dB Set this parameter through ADD UCELLSELRESEL, query it through LST UCELLSELRESEL, and



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


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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 += ,

InRs, smeans serving cell. InRn, nmeans neighbor cell. The offset Qoffset1s,nis used for Qoffsets,nto calculateRn. The hysteresis Qhyst1sis used

for Qhyststo calculateRs. The UE shall rank the cells according to the R criterion, derive Qmeas,nandQmeas,sand

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 reselectthat FDD cell.

If an FDD cell is ranked as the best cell and the quality measure for cell selection andreselection 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,nand Qmeas,sand then calculating the R values of the FDD cells.The offset Qoffset2s,nis used for Qoffsets,nto calculateRn, the hysteresis Qhyst2sis

used for Qhyststo calculateRs.


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


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

Set this parameter through ADD UCELLSELRESEL, query it through LST UCELLSELRESEL, andmodify it through MOD UCELLSELRESEL.


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

Value range: 0~20 Physical value range: 0~40; step: 2 Physical unit: dB Set this parameter through ADD UCELLSELRESEL, query it through LST UCELLSELRESEL, and


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 value range: 0~40; step: 2

Physical unit: dB

Set this parameter through ADD UCELLSELRESEL, query it through LST UCELLSELRESEL, andmodify it through MOD UCELLSELRESEL.


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

Value range: {{0~20}, {255}} Physical value range: 0~40; step: 2 Physical unit: dB

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


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 value range: 0~40; step: 2 Physical unit: dB Set this parameter through ADD UCELLSELRESEL, query it through LST UCELLSELRESEL, and



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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 UINTRAFREQNCELL / ADD UINTERFREQNCELL, query it

through LST UINTRAFREQNCELL / LST UINTERFREQNCELL, and modify it through MOD

UINTRAFREQNCELL / MOD UINTERFREQNCELL.

ConnQoffset1sn Content: Offset of cell CPICH RSCP measurement value in cell selection or reselection when the UE is

in connected mode. Value range: -50~+50 Physical value range: -50~+50; step: 1 Physical unit: dB

Set this parameter through ADD UINTRAFREQNCELL / ADD UINTERFREQNCELL, query itthrough LST UINTRAFREQNCELL / LST UINTERFREQNCELL, and modify it through MOD



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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. Value range: -50~+50 Physical value range: -50~+50; step: 1 Physical unit: dB Set this parameter through ADD UINTRAFREQNCELL / ADD UINTERFREQNCELL, query it

through LST UINTRAFREQNCELL / LST UINTERFREQNCELL, and modify it through MOD


ConnQoffset2sn Content: Offset of cell CPICH Ec/No measurement value in cell selection or reselection when the UE is

in connected mode. Value range: -50~+50 Physical value range: -50~+50; step: 1 Physical unit: dB

Set this parameter through ADD UINTRAFREQNCELL / ADD UINTERFREQNCELL, query itthrough LST UINTRAFREQNCELL / LST UINTERFREQNCELL, and modify it through MOD



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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 performany 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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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 thenetwork to the UE in the messages ATTACH ACCEPT and ROUTING AREA UPDATE ACCEPT.

The value of T3312 shall be unique within an RA.


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.


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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. ThisIMSI 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.


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 value range: 0~1530; step: 6 Physical unit: min Set this parameter through ADD UCNDOMAIN, query it through LST UCNDOMAIN, modify it

through MOD UCNDOMAIN.

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/detachprocedure. 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 UCNDOMAIN, query it through LST UCNDOMAIN, modify it



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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, transmitspaging 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 areply 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 tocarry out the system message update, so that the UE can read the updated system message.


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Paging Type 1

If UE is in the idle or CELL/URA_PCH state, the paging

message will be transmitted on PCCH with paging type 1

CN 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 forCELL_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, UEperforms 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 iscovered 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 thePAGING TYPE 1 message to these cells through the PCCH.


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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

CN SRNC UE

RANAPRANAP

PAGING

RRCRRC

DCCH: PAGING TYPE 2

Paging type 2:

If UE is in CELL_DCH or CELL_FACH statethe 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.


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Typical Call Flow of UE UE NAS UE AS NS S MSC

paging

AUTHENTICATION REQUEST

AUTHENTICATION RESPONSE

RR_SECURITY_CONTROL_REQ

(IK CK)

Security mode control

SETUP

CALL CONFIRM

ALERT

CONNECT

CONNECT ACKNOWLEDGE

RAB setup process

paging

RR_EST_REQ (PAGING RESPONSE)

RR_PAING_IND

INITIAL_DIRECT_TRANSFER

(PAGING RESPONSE)

RANAPRANAP

RRC 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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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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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, 2and the requirement is the calculated CELL SFN must be below itsmaximum 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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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 thered 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.


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PICH

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).


Parameters of DRX DRXCyclelenCoef

Parameter name: DRX cycle length coefficient

Recommended value: 6

PICHMode

Parameter name: PICH mode

Recommend value: V36


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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 UCNDOMAIN, query it through LST UCNDOMAIN, and modify it


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 UPICH, query it through LST UPICH.


Parameters of DRX (Cont.)

MaccPageRepeatTimes

Parameter name: Repeat Times of Macc Paging


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. For details, refer to the 3GPPTS 25.331 protocol.

Value range: 0~2 Physical value range: 0~2 Physical unit: None Set this parameter through SET UDPUCFGDATA, query it through LST UDPUCFGDATA.


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Copyrigh t 2009 Huawei Technologies Co., Ltd. All rights reserved.

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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Copyright 2009 H uawei Technologies Co., Ltd. All rights reserved.

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


Random Access Channel

AICH accessslots

10 ms

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


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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.


RACH Sub-Channels

SFNmod 8

Random access sub-channels number

0 1 2 3 4 5 6 7 8 9 10 11

0 0 1 2 3 4 5 6 7

1 12 13 14 8 9 10 11

2 0 1 2 3 4 5 6 7

3 9 10 11 12 13 14 8

4 6 7 0 1 2 3 4 5

5 8 9 10 11 12 13 14

6 3 4 5 6 7 0 1 2

7 8 9 10 11 12 13 14

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 UPRACHBASIC, query them through LST

UPRACH.


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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 UPRACHASC, modify it through MOD UPRACHASC,and remove it through RMV UPRACHASC.


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


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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 (11to 15) are barred. Otherwise, Emergency Calls are allowed.


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 UPRACHACTOASCMAP, modify it through MODUPRACHACTOASCMAP, and remove it through RMV UPRACHACTOASCMAP.


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Random Access ProcedureSTART

Choose a RACH sub channel fromavailable ones

Get available signatures

Set Preamble Retrans Max

Set Preamble_ Initial_Power

Send a preamble

Check the corre sponding 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 & Commande d Preamblepower-maximum allowed power < 6

dB

Choose a signature andincrease preamble transmit power

Set physical status to be Nack

on 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 powerincreased by Power Ramp Step

N

Y

Send the correspo nding message part

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.


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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 theselected signature is detected in the downlink access slot corresponding to the selected uplinkaccess 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 isequal toMaxallowedUlTxPower.

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 accessprocedure.

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 randomaccess procedure.

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


RRC Connection Message

Typical RRC connection messages:

RRC_CONNECTION_REQUEST

RRC_CONNECTION_SETUP

RRC_CONNECTION_SETUP_COMPLETE

RRC_CONNECTION_RELEASE


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

The UE sends a RRC CONNECTIONREQUESTmessage from the cell where it camps to the RNC. The RNC allocates related resources for the UE and sends an RRC CONNECTIONSETUPmessage

to the UE. The UE sends a RRC CONNECTIONSETUP COMPLETEmessage to the RNC. The RRC

connectionsetup ends.


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 REQUESTmessage. It is stopped

when UE receives the RRC CONNECTION SETUPmessage. 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 UIDLEMODETIMER, query it through LST UIDLEMODETIMER.

N300 Content: Maximum number of retransmissions of the RRC CONNECTION REQUESTmessage. Value range: 0~7 Physical value range: 0~7 Physical unit: None Set this parameter through SET UIDLEMODETIMER, query it through LST UIDLEMODETIMER.


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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 consecutiveN312 "in sync" indications from L1. It indicates physical channel setup failure upon the expiry of thetimer.

Value range: 1~15 Physical value range: 1~15s

Physical unit: s Set this parameter through SET UIDLEMODETIMER, query it through LST UIDLEMODETIMER.

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


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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


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

Establishment cause IE in the RRC CONNECTION REQUESTmessage. 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 URRCESTCAUSE, query it through LST URRCESTCAUSE.

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 URRCESTCAUSE, query it through LST URRCESTCAUSE.


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RRC Connection Establish Channel

Type and Bit Rate EFachSwitch

Parameter name: switch for RRC established on E_FACH


EFachSwitch Content: This parameter specifies whether the RRC connection is established preferentially on the E-

FACH. If this parameter is set to ON and both the UE and the serving cell support E-FACH, then theRRC connection is established preferentially on the E-FACH, regardless of the setting of SigChType.

According to the related protocols, the UE cannot transmit signals over the FACH if both the UE andthe cell support E-FACH. Thus, if this parameter is set to OFF and both the UE and the serving cellsupport E-FACH, then the RRC connection can only be established on the non-FACH, even if the

SigChType is set to FACH. Otherwise, the RRC connection is established on the corresponding channel

according to the setting of SigChType

Value range: OFF, ON

Set this parameter through SET URRCESTCAUSE, query it through LSTURRCESTCAUSE.


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Foreword

Power control categories:

Uplink power control

Downlink power control

Power control types:

Open loop power control

Closed loop power control

Inner loop power control

Outer loop power control

The WCDMA system is an interference-limited system, and the most important way to restrainsystem interference is power control. The core purpose of power control is to minimized the

power of transmitting signals while ensuring Quality of Service (QoS).In the uplink, a UE emitting too high power will cause unacceptable competing interference on

the NodeB in comparison to signals coming from UEs at the cell edge. This is called near-fareffect. To avoid near-far effect, uplink power control is required.

In the downlink, the system capacity is determined by the total code power. Therefore, it isnecessary to keep the transmit power at the lowest possible level while still ensuring signal

quality at the UE.At open loop power control, the initial transmit power is calculated. This method is rather

inaccurate and it is only applied at the beginning of a connection setup.At closed loop power control, the transmitter dynamically adjusts its transmit power according

to the feedback from the receiver of the other side. Closed loop power control is furtherclassified into the following types:Inner loop power control directly adjusts the transmit power of the transmitter by using power

control commands.Outer loop power control indirectly controls the transmit power of the transmitter.


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References

3GPP TS 25.211: Physical Channels and Mapping of

Transport Channels onto Physical Channels (FDD)

3GPP TS 25.214: Physical Layer Procedures (FDD)

3GPP TS 25.331: RRC Protocol Specification

3GPP TS 25.433: UTRAN Iub Interface NodeB

Application Part (NBAP) Signaling


Objectives

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

Describe the purpose and function of power control

Perform parameters modification of open loop power

control

Perform parameters modification of inner loop power

control

Perform parameters modification of outer loop power

control


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Purpose of Uplink Power Control

Uplink transmission character:

Self-interference system

Uplink capacity is limited by interference level

Near-far effect

Fading

Uplink power control function:

Ensure uplink quality with minimum transmission power

Decrease interference to other UE, and increase capacity

Solve the near-far effect

Save UE transmission power

CDMA system have the embedded characteristics of self-interference, for uplink one users

transmission power become interference to others.The more connected users, the higher interference. Generally the capacity is limited by

interference level.WCDMA suffer from Near-far effect, which means if all UE use the same transmission power,

the one close to the NodeB may block the entire cell.Uplink power control can guarantee the service quality and minimize the required transmission

power. It will resolve the near-far effect and resist fading of signal propagation. By lowering theuplink interference level, the system capacity will be increased.


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Purpose of Downlink Power Control

Downlink transmission character:

Interference among different subscribers

Interference from other adjacent cells

Downlink capacity is limited by NodeB transmission power

Fading

Downlink power control function:

Ensure downlink quality with minimum transmission power

Decrease interference to other cells, and increase capacity

Save NodeB transmission power

The downlink has different characteristics from the uplink, for downlink interference is caused

by multi-path, part of one users power also become interference to others.Downlink power from adjacent cells also is one part of interference to the own cell.

Transmission power of NodeB is shared by all users channels, so downlink capacity usually isconsidered to be limited by transmission power.

Downlink power control also can guarantee the service quality and minimize the requiredtransmission power, so the capacity is maximized in case that interference is lowered.


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Effect of Power Control

Time (ms)

0 200 400 600 800-20

-15

-10

-5

0

5

10

15

20

Relativepower(dB)

Channel Fading

Transmitting power

Receiving power

Because of channel fading in mobile communication system, the radio signal is deteriorated and

fluctuated, the fast power control become one key technology to resist this phenomenon.In this figure, the channel fading is compensated by the transmitting power, which is adjusted

by the fast power control, so the receiving power is almost constant and the radio propagationcondition is improved.


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Power Control Classification

Open loop power control:

Uplink/Downlink open loop power control

Closed loop power control:

Uplink/Downlink inner loop power control

Uplink/Downlink outer loop power control

In WCDMA system, power control includes open loop and closed loop power control.

Open loop power control is used to determine the initial transmission power, and the closedloop power control adjusts the transmission power dynamically and continuously during the

connection.For uplink, the UEs transmission power is adjusted; and for downlink, the NodeBs

transmission power is adjusted.


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Power Control for Physical Channels

Power control methods are adopted for these physical

channels:

" : can be applied; : can not be appliedPhysicalChannel

Open LoopPowerControl

Closed Loop Power Control

Inner Loop PowerControl

Outer LoopPower Control

DPDCH

DPCCH

SCH

PCCPCH

SCCPCH PRACH

AICH

PICH

Open loop power control is used in two cases:

1. to decide the initial transmission power of PRACH;2. to decide the initial transmission power of DPCCH / DPDCH.

Closed loop power control is only applied on DPCCH and DPDCH.For other common channels, power control is not applied, they will use fixed transmission

power:The PCPICH power is defined by the PCPICHPowerparameter as an absolute value in dBm.

All other common channels power is defined in relation with the PCPICHPower parameter,and measured in dB.


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Common Physical Channel PowerParameters

MaxTxPower

Parameter name: Max transmit power of cell [0.1dBm]


PCPICHPower

Parameter name: PCPICH transmit power [0.1dBm]


MaxTxPowerContent: The sum of the maximum transmit power of all DL channels in a cell.Value range: 0 to 500Physical value range: 0 to 50; step: 0.1Physical unit: dBm

Set this parameter through ADD UCELLSETUP and modify it through MOD UCELL.

PCPICHPowerContent: This parameter should be set based on the actual environment and the downlink coverage should be

guaranteed firstly. If PCPICH transmit power is configured too great, the cell capacity will be decreased, for powerresources is occupied by common channel and the interference to traffic channels is also increased.Value range: -100 to 500Physical value range: -10 to 50; step: 0.1Physical unit: dBmSet this parameter through ADD UPCPICH, query it through LST UPCPICH and modify it through MOD UCELL.


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Common Physical Channel PowerParameters (Cont.)

PSCHPowerand SSCHPower

Parameter name: PSCH / SSCH transmit power [0.1dB]


BCHPower

Parameter name: BCH transmit power [0.1dB]


PSCHPowerand SSCHPowerContent: The offset of the PSCH/SSCH transmit power from the PCPICH transmit power in a cell .Value range: -350 to 150Physical value range: -35 to 15; step: 0.1Physical unit: dB

For PSCH Power, set it through ADD UPSCH, and query it through LST UPSCH; for SSCH Power, set it through

ADD USSCH, and query it through LST USSCH. And modify them through MOD UCELL.

BCHPowerContent: The offset of the BCH transmit power from the PCPICH transmit power in a cell.Value range: -350 to 150Physical value range: -35 to 15; step: 0.1Physical unit: dBSet this parameter through ADD UBCH, query it through LST UBCH, and modify it through MOD UCELL.


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MaxFachPower

Parameter name: Max transmit power of FACH [0.1dB]


PCHPower

Parameter name: PCH transmit power [0.1dB]


MaxFachPowerContent: The offset between the FACH transmit power and PCPICH transmit power in a cell.Value range: -350 to 150Physical value range: -35 to 15; step: 0.1Physical unit: dB

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

PCHPowerContent: The Offset of the PCH transmit power from the PCPICH transmit power in a cell.Value range: -350 to 150Physical value range: -35 to 15; step: 0.1Physical unit: dBSet this parameter through ADD UPCH, query it through LST UPCH, and modify it through MOD USCCPCH.


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AICHPowerOffset

Parameter name: AICH power offset


PICHPowerOffset

Parameter name: PICH power offset


AICHPowerOffsetContent: The difference between the transmit power of AICH and that of PCPICH.Value range: -22 to 5Physical value range: -22 to 5; step: 1Physical unit: dB

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

through MOD UAICHPWROFFSET.

PICHPowerOffsetContent: The difference between the transmit power of PICH and that of PCPICH.Value range: -10 to 5Physical value range: -10 to 5; step: 1Physical unit: dBSet this parameter through ADD UCHPWROFFSET, query it through LST UCHPWROFFSET, and modify it

through MOD UPICHPWROFFSET.


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Open Loop Power Control Overview

Purpose

Calculate the initial transmission power of uplink / downlink

channels

Principle Estimates the downlink signal power loss on propagation path

Path loss of the uplink channel is related to the downlink channel

Application

Open loop power control is applied only at the beginning of

connection setup to set the initial power value

In downlink open loop power control, the initial transmission power is calculated according to the downlink path

loss between NodeB and UE.In uplink, since the uplink and downlink frequencies of WCDMA are in the same frequency band, a significant

correlation exists between the average path loss of the two links. This make it possible for each UE to calculate the

initial transmission power required in the uplink based on the downlink path loss.However, there is 90MHz frequency interval between uplink and downlink frequencies, the fading between the

uplink and downlink is uncorrelated, so the open loop power control is not absolutely accurate.


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PRACH Open Loop Power Control

5. Downlink Synchronization

UE NodeB SRNC

DCH - FP

Allocate RNTISelect L1 and L2parameters

RRCRRC

NBAPNBAP

3. Radio Link Setup Response

NBAPNBAP2. Radio Link Setup Request

RRCRRC7. CCCH: RRC Connection Setup

Start RXdescription

Start TXdescription

4. ALCAP Iub Data Transport Bearer Setup

RRCRRC9.DCCH: RRC Connection Setup Complete

6. Uplink Synchronization

NBAPNBAP8. Radio Link Restore Indication

DCH - FP

DCH - FP

DCH - FP

Open loop powercontrol of PRACH

1. CCCH: RRC Connection Request

In access procedure, the first signaling RRC CONNECTION REQUESTis transmitted in message part on

PRACH.Before PRACH message part transmission, UE will transmit PRACH preamble, and the transmission power of first

preamble is calculated by this PRACH open loop power control.


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Copyright 2009 Hu awei Technologies Co., Ltd. All rights reserved.

PRACH Open Loop Power Control

When UE needs to set up a RRC connection, the initial

power of uplink PRACH preamble can be calculatedaccording to the following formula:

lueConstantvaceinterferenUL

CPICH_RSCP-rPCPICHPowe=ernitial_PowPreamble_I

++

In this formula, wherePCPICHPower defines the PCPICH transmit power in a cell. It is broadcast in SIB5.

CPICH_RSCP means received signal code power, the received power measured on the PCPICH. The measurement

is performed by the UE.UL interference is the UL RTWP measured by the NodeB. It is broadcast in SIB7.Constantvaluecompensates for the RACH processing gain. It is broadcast in SIB5.The initial value of PRACH power is set through open loop power control. UE operation steps are as follows:1. Read Primary CPICH DL TX power, UL interference and Constant value from system information;2. Measure the value of CPICH_RSCP;

3. Calculate the Preamble_Initial_Power of PRACH.


PRACH Open Loop Power ControlParameters

Constantvalue

Parameter name: Constant value for calculating initial TX

power



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ConstantvalueContent: It is used to calculate the transmit power of the first preamble in the random access process.Value range: -35 to -10Physical value range: -35 to -10; step: 1Physical unit: dBSet this parameter through ADD UPRACHBASIC, query it through LST UPRACH, and modify it through MODUPRACHUUPARAS.


PRACH Open Loop Power Control (Cont.)

Timing relationship of PRACH and AICH:

AICH

PRACH

1 access slot

p-a

p-mp-p

Pre-

amble

Pre-

ambleMessage

part

Acq.Ind.

After UE transmit the first Preamble on PRACH, it will wait for the corresponding AI (Acquisition Indicator) on

the AICH. The timing relationship of PRACH and AICH is shown in above figure.There will be 3 parameters used to define the timing relationship:

p-p: time interval between two PRACH preambles. p-pis not a fixed value, it is decided by selecting access slot ofPRACH preambles.

Here p-phas one restriction, it must be longer than a minimum value p-p min, namelyp-pp-p min.

p-a: time interval between PRACH preamble and AICH Acquisition Indicator. If UE sends the PRACH preamble,

it will detect the responding AI after p-atime.p-m: time interval between PRACH preamble and PRACH message part. If UE sends the PRACH preamble and

receives positive AI from the AICH, it will send the message part after p-mtime.


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PRACH Open Loop Power ControlParameters (Cont.)

AICHTxTiming

Parameter name: AICH transmission timing

Content:

WhenAICHTXTIMING= 0,

p-p,min = 15360 chips, p-a= 7680 chips, p-m= 15360 chips

WhenAICHTXTIMING= 1,

p-p,min = 20480 chips, p-a= 12800 chips, p-m= 20480 chips


AICHTxTimingContent: Transmission timing information of an AICH. "0" indicates that there are 7680 chips offset between the

access preamble of the PRACH and AICH. "1" indicates that there are 12800 chips offset between them.Value range: 0 to 1Physical value range: 0 to 1; step: 1

Set this parameter through ADD UAICH, query it through LST UAICH, and modify it needs de-activated the cell

through DEA UCELL. After the old configuration of AICH is deleted through RMV UAICH , a new AICH can be

established through ADD UAICH.


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PRACH Open Loop Power Control (Cont.)

Power ramping for preamble retransmission:

Power Ramp Step

Power Offset Pp-m

Preamble_Initial_Power

Messagepart

Pre-amblePre-

amble

Pre-

amblePre-amble

1 3 N2

After UE transmit the first preamble,

If no positive or negative AI on AICH is received afterp-a

time,UE shall increase the preamble power by PowerRampStep, and retransmit the preamble.

A preamble ramping procedure consists of several preamble ramping cycles, which cannot exceed Mmax.In each cycle, the UE retransmits the preamble until the UE receives the acquisition indicator or the

number of retransmissions has reached PreambleRetransMax.

If a negative AI on AICH is received by the UE after p-atime,which indicates rejection of the preamble, the UE shall wait for a certain Back-off Delay and re-initiate

a new random access process. The parametersNB01minandNB01maxdefine the lower and upper limitsof the back-off delay. If the value ofNB01minis equal to that ofNB01max, it means that the

retransmission period of the preamble part is fixed.

When a positive AI on AICH is received by UE after p-atime,it will transmit the random access message after the uplink access slot of the last preamble.

wcdma bsc6900 r11 features and algorithms

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