3 WCDMA RAN12 Power Control Algorithm and Parameters ISSUE1.00

8/13/2019 3 WCDMA RAN12 Power Control Algorithm and Parameters ISSUE1.00

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The WCDMA system is an interference-limited system, and the most

important way to restrain system interference is power control. The corepurpose of power control is to minimized the power of transmittingsignals while ensuring Quality of Service (QoS).In the uplink, a UE emitting too high power will cause unacceptablecompeting interference on the NodeB in comparison to signals comingfrom UEs at the cell edge. This is called near-far effect. To avoid near-fareffect, uplink power control is required.In the downlink, the system capacity is determined by the total codepower. Therefore, it is necessary to keep the transmit power at thelowest possible level while still ensuring signal quality at the UE.

At open loop power control, the initial transmit power is calculated. Thismethod is rather inaccurate and it is only applied at the beginning of aconnection setup.

At closed loop power control, the transmitter dynamically adjusts itstransmit power according to the feedback from the receiver of the otherside. Closed loop power control is further classified into the followingtypes:

Inner loop power control directly adjusts the transmit power of thetransmitter by using power control commands.Outer loop power control indirectly controls the transmit power ofthe transmitter.


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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 thecapacity is limited by interference level.WCDMA suffer from Near-far effect, which means if all UE use thesame transmission power, the one close to the NodeB may block theentire cell.Uplink power control can guarantee the service quality and minimizethe required transmission power. It will resolve the near-far effect andresist fading of signal propagation. By lowering the uplink interference

level, the system capacity will be increased.


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The downlink has different characteristics from the uplink, for downlink

interference is caused by multi- path, part of one users power alsobecome interference to others.Downlink power from adjacent cells also is one part of interference to theown cell.Transmission power of NodeB is shared by all users channels, sodownlink capacity usually is considered to be limited by transmissionpower.Downlink power control also can guarantee the service quality andminimize the required transmission power, so the capacity is maximized

in case that interference is lowered.


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Because of channel fading in mobile communication system, the radio

signal is deteriorated and fluctuated, the fast power control become onekey technology to resist this phenomenon.In this figure, the channel fading is compensated by the transmittingpower, which is adjusted by the fast power control, so the receivingpower is almost constant and the radio propagation condition is improved.


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

power control.Open loop power control is used to determine the initial transmissionpower, and the closed loop power control adjusts the transmissionpower 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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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 usefixed transmission power:

The PCPICH power is defined by the PCPICHPower parameteras an absolute value in dBm.

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


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MaxTxPower

Content: The sum of the maximum transmit power of all DLchannels in a cell.Value range: 0 to 500Physical value range: 0 to 50; step: 0.1Physical unit: dBmSet this parameter through ADD UCELLSETUP and modify itthrough MOD UCELL.

PCPICHPower

Content: This parameter should be set based on the actualenvironment and the downlink coverage should be guaranteedfirstly. If PCPICH transmit power is configured too great, the cellcapacity will be decreased, for power resources is occupied bycommon channel and the interference to traffic channels is alsoincreased.Value range: -100 to 500Physical value range: -10 to 50; step: 0.1Physical unit: dBmSet this parameter through ADD UPCPICH, query it through LSTUPCPICH and modify it through MOD UCELL.


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PSCHPower and SSCHPower

Content: The offset of the PSCH/SSCH transmit power from thePCPICH transmit power in a cell .Value range: -350 to 150Physical value range: -35 to 15; step: 0.1Physical unit: dBFor PSCH Power, set it through ADD UPSCH, and query itthrough LST UPSCH; for SSCH Power, set it through ADDUSSCH, and query it through LST USSCH. And modify themthrough MOD UCELL.

BCHPower

Content: The offset of the BCH transmit power from the PCPICHtransmit 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 LSTUBCH, and modify it through MOD UCELL.


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MaxFachPower

Content: The offset between the FACH transmit power andPCPICH transmit power in a cell.Value range: -350 to 150Physical value range: -35 to 15; step: 0.1Physical unit: dBSet this parameter through ADD UFACH, query it through LSTUFACH.

PCHPower

Content: The Offset of the PCH transmit power from the PCPICHtransmit 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 LSTUPCH, and modify it through MOD USCCPCH.


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AICHPowerOffset

Content: The difference between the transmit power of AICH andthat of PCPICH.Value range: -22 to 5Physical value range: -22 to 5; step: 1Physical unit: dBSet this parameter through ADD UCHPWROFFSET, query itthrough LST UCHPWROFFSET, and modify it through MODUAICHPWROFFSET.

PICHPow erOffset

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


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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 inthe same frequency band, a significant correlation exists between theaverage path loss of the two links. This make it possible for each UE tocalculate the initial transmission power required in the uplink based onthe downlink path loss.However, there is 90MHz frequency interval between uplink anddownlink frequencies, the fading between the uplink and downlink isuncorrelated, so the open loop power control is not absolutely accurate.


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In access procedure, the first signaling RRC CONNECTION REQUEST

is transmitted in message part on PRACH.Before PRACH message part transmission, UE will transmit PRACHpreamble, and the transmission power of first preamble is calculated bythis PRACH open loop power control.


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In this formula, where

PCPICHPower defines the PCPICH transmit power in a cell. It isbroadcast in SIB5.CPICH_RSCP means received signal code power, the receivedpower measured on the PCPICH. The measurement isperformed by the UE.UL interference is the UL RTWP measured by the NodeB. It isbroadcast in SIB7.

Constantvalue compensates for the RACH processing gain. It isbroadcast in SIB5.

The initial value of PRACH power is set through open loop powercontrol. UE operation steps are as follows:

1. Read Primary CPICH DL TX power, UL interference andConstant value from system information;2. Measure the value of CPICH_RSCP;3. Calculate the Preamble_Initial_Power of PRACH.


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Cons tan tva lue

Content: It is used to calculate the transmit power of the firstpreamble 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 throughLST UPRACH, and modify it through MOD UPRACHUUPARAS.


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After UE transmit the first Preamble on PRACH, it will wait for the

corresponding AI (Acquisition Indicator) on the AICH. The timingrelationship of PRACH and AICH is as follow:There will be 3 parameters used to define the timing relationship:

p -p : time interval between two PRACH preambles. p-p isnot a fixed value, it is decided by selecting access slot ofPRACH preambles.

Here p-p has one restriction, it must be longer than aminimum value p-p min , namely p-p p-p min .

p -a : time interval between PRACH preamble and AICH Acquisition Indicator. If UE sends the PRACH preamble, itwill detect the responding AI after p-a time.

p -m : time interval between PRACH preamble and PRACHmessage part. If UE sends the PRACH preamble andreceives positive AI from the AICH, it will send themessage part after p-m time.


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AICHTxTiming

Content: Transmission timing information of an AICH. "0" indicatesthat there are 7680 chips offset between the access preamble of thePRACH and AICH. "1" indicates that there are 12800 chips offset

between them.Value range: 0 to 1Physical value range: 0 to 1; step: 1Set this parameter through ADD UAICH, query it through LST UAICH,and modify it needs de-activated the cell through DEA UCELL. Afterthe old configuration of AICH is deleted through RMV UAICH , a new

AICH can be established through ADD UAICH.


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PowerRampStep

Content: The power increase step of the random accesspreambles transmitted before the UE receives the acquisitionindicator in the random access process.Value range: 1 to 8Physical value range: 1 to 8; step: 1Physical unit: dBSet this parameter through ADD UPRACHBASIC, query it throughLST UPRACH, and modify it through MOD UPRACHUUPARAS.

PreambleRetransMax

Content: The maximum number of preambles transmitted in apreamble ramping cycle.Value range: 1 to 64Physical value range: 1 to 64; step: 1Set this parameter through ADD UPRACHBASIC, query it throughLST UPRACH, and modify it through MOD UPRACHUUPARAS.


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Mmax

Content: Maximum number of random access preamble loops.Value range: 1 to 32Physical value range: 1 to 32; step: 1Set this parameter through ADD URACH, query it through LSTURACH, and modify it first de-activated the cell through DEAUCELL, then MOD URACH, finally ACT UCELL.

NB01min / NB01max

Content: Lower/Upper limit of random access back-off delay.Value range: 0 to 50Physical value range: 0 to 50; step: 1Physical unit: frameSet this parameter through ADD URACH, query it through LSTURACH, and modify it first de-activated the cell through DEAUCELL, then MOD URACH, finally ACT UCELL.


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PowerOffsetPpm

Content: The power offset between the last access preamble andthe message control part. The power of the message control partcan be obtained by adding the offset to the access preamblepower.Value range: -5 to 10Physical value range: -5 to 10; step: 1Physical unit: dBSet this parameter through ADD UPRACHTFC, query it throughLST UPRACH, and modify it de-activated the cell through DEA

UCELL . After the old configuration of PRACH is deleted throughRMV UPRACHTFC , a new parameters can be establishedthrough ADD UPRACHTFC.

The power of the data part is calculated with the following formula:, where

Pcontrol is the power for the control part.d is the power gain factor for the data part. The value is definedby the GainFactorBetaD parameter.c is the power gain factor for the control part. The value isdefined by the GainFactorBetaC parameter.


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MaxAl lowedUlTxPower

Content: The maximum allowed uplink transmit power of a UE inthe cell, which is related to the network planning.Value range: -50 to 33Physical value range: -50 to 33; step: 1Physical unit: dBmSet this parameter through ADD UCELLSELRESEL, query itthrough LST UCELLSELRESEL, and modify it through MODUCELLSELRESEL.


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According to the RRC connection establishment procedure, after RNC

received the RRC CONNECTION REQUEST message, and NodeB setup the radio link for UE, then Iub interface resources is establishedbetween NodeB and RNC.When DCH-FP of Iub interface finished downlink and uplinksynchronization, the downlink DPCH starts to transmit, and DPCH initialtransmission power is calculated through open loop power control.


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The downlink DPCCH consists of three fields: TFCI, TPC, and pilot. Their

power is set as the offset reference to the power of the downlinkDPDCHs.The downlink power on the DPCCH and its associated DPDCHs issimultaneously regulated. Thus, power control adjusts the power of theDPCCH and DPDCHs with the same step, and the power offset betweenthe DPCCH and the DPDCH keeps constant.Power offsets between the DPCCH and the DPDCH in the downlink areidentical for all TFCs in the TFCS, whereas in the uplink the poweroffsets are TFC-dependent.

The power offsets of TFCI, TPC and pilot fields of the DPCCH referenceto the power of DPDCHs are fixed to 0dB, 3dB, and 3dB respectively.


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RlMaxDlPwr

Content: This parameter should fulfill the coverage requirement ofthe network planning, and the value is relative to PCPICH transmitpower.Value range: -350 to 150Physical value range: -35 to 15; step: 0.1Physical unit: dBSet this parameter through ADD UCELLRLPWR , query it throughLST UCELLRLPWR, and modify it through MOD UCELLRLPWR.

RlMinDlPwr

Content: This parameter should consider the maximum downlinktransmit power and the dynamic range of power control, and thevalue is relative to PCPICH transmit power.Value range: -350 to 150Physical value range: -35 to 15; step: 0.1Physical unit: dBSet this parameter through ADD UCELLRLPWR, query it throughLST UCELLRLPWR, and modify it through MOD UCELLRLPWR.


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Both downlink open loop and close loop power control will be limited by

these parameters.


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According to the RRC connection establishment procedure, after RNC

sent the RRC CONNECTION SETUP message, UE will try tosynchronize with NodeB, and the uplink DPCCH starts to transmit, hereDPCCH initial transmission power is calculated through open loop powercontrol.The power of the uplink DPDCH is set as a power offset (d/c)reference to the uplink DPCCH. The uplink DPCCH and DPDCHs aretransmitted through different channel codes. To meet a given QoSrequirement on the transport channels, different TFCs use different poweroffsets.The RNC has a set of reference values (c,ref and d,ref) that are storedfor each predefined Radio Access Bearer (RAB) or Signaling RadioBearer (SRB). c,ref and d,ref can be configured by BETAC andBETAD on the RNC.The RNC calculates a new power offset for each TFC based on thereference values dynamically and sends the power offset to the UE.


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For Huawei, DPCCH_Power_Offset is calculated with the following

formula:

Where:The PCPICHPower parameter defines the PCPICH transmitpower in a cell. This value is broadcast in SIB5.Uplink interference is the uplink RTWP measured by the NodeBand sent to the UE through the SIB7.The DefaultConstantValue parameter reflects the target Ec/No ofthe uplink DPCCH.

tValue s DefaultConce InterferenULr PCPICHPoweOffset Power DPCCH tan _ _


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MaxUlTxPowerforConv

MaxUlTxPowerforStr MaxUlTxPowerforInt

MaxUlTxPowerforBac

Content: The maximum UL transmit power for specific services ina cell. It is based on the UL coverage requirement of the specificservices designed by the network planning.Value range: -50 to 33Physical value range: -50 to 33; step: 1Physical unit: dBmSet this parameter through ADD UCELLCAC, query it throughLST UCELLCAC, and modify it through MOD UCELLCAC.


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Inner Loop Power Control:

The receiver compares SIR mea (measured SIR) with SIR tar (target SIR),and decide the TPC to send:

If SIR mea is greater than SIR tar , the TPC is set as 0 to decrease

transmission power;

If SIR mea is less than SIR tar , the TPC is set as 1 to increase

transmission power.

TPC is sent to the transmitter in DPCCH, the transmitter will adjust the

power according to the value of received TPC.

Through inner loop power control, the SIR mea can be ensured to

approach SIR tar .

Outer Loop Power Control:The receiver compares BLER mea (measured BLER) with BLER tar (targetBLER), and decide how to set the SIR tar :

If BLER mea is greater than BLER tar , the SIR tar is increased;

If BLER mea is less than BLER tar , the SIR tar is decreased.

The adjusted SIR tar is sent for the inner loop power control, then it will be

used in previous process to guide the transmitter power adjustment.

Through outer loop power control, the BLER mea can be ensured toapproach BLER tar .


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RNC sends SIR tar (target SIR) to NodeB and then NodeB compares

SIR mea (measured SIR) with SIR tar :If the estimated SIR is greater than the target SIR, NodeB sendsTPC 0 to UE on downlink DPCCH TPC field;Otherwise, NodeB sends TPC 1 to UE.

After reception of one or more TPC, UE shall derive a single TPC_cmd(TPC command, with value among -1, 0, 1):

Two algorithms could be used by the UE for deriving theTPC_cmd, those are PCA1 and PCA2 (PCA means PowerControl Algorithm).

For UE is in soft handover state, more than one TPC is received,so firstly multiple TPC_cmd is combined.

When deriving the combined TPC_cmd, UE shall adjust the transmitpower of uplink DPCCH with a step UL Closed Loop Power Control StepSize, as following:

DPCCH = TPC TPC_cmdThis adjustment is executed on the DPCCH, then associated DPDCHtransmit power is calculated according to DPDCH / DPCCH power ratio

d / c.


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When UE has single radio link, only one TPC will be received in each slot.

In this case, the value of TPC_cmd shall be derived by PCA1 as follows:If the received TPC is equal to 0, then TPC_cmd for that slot is -1;If the received TPC is equal to 1, then TPC_cmd for that slot is 1.

According to DPCCH channel structure, there are 15 time slots in a 10msradio frame, and the control is performed once in each time slot, so thefrequency of uplink inner loop PCA1 is 1500Hz.


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When UE has single radio link, only one TPC will be received in each slot.

In this case, the value of TPC_cmd shall be derived by PCA2 as follows:For the first 4 slots of a set, TPC_cmd = 0.For the fifth slot of a set, UE make the decisions on as follows:

If all 5 TPCs within a group are 1, then TPC_cmd = 1 inthe 5th slot;

If all 5 TPCs within a group are 0, then TPC_cmd = -1 inthe 5th slot;

Otherwise, TPC_cmd = 0 in the 5th slot.

According to DPCCH channel structure, there are 15 time slots in a 10msradio frame, and the control is performed once in each 5-slot group, sothe frequency of uplink inner loop PCA2 is 300Hz.


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On the NodeB side, there are two phases during the soft handover state:

Uplink synchronization phaseThe NodeB should send durative TPC = 1 to the newly -addedRL before successful synchronization.Multi-radio link phaseEach NodeB and each cell will estimate the SIR individually andthe general TPC individually. Therefore, the UE may receivedifferent TPC from different RLS.

Especially, when UE is in softer handover state, it means UE has radiolinks to the same NodeB, in this case, these RLs (Radio Link) belong to

the same RLS (Radio Link Set), and the all TPCs are the same fromeach RL.


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When UE is in soft handover state, multiple TPC will be received in each

slot from different cells in the active set. UE will generate the TPC_cmdby PCA1 as follows:1. Combine the TPC from the same RLS and derive the Wi

When the RLs (Radio Link) are in the same RLS (Radio Link Set),they will transmit the same TPC in a slot. In this case, the TPCsfrom the same RLS shall be combined into one.

After combination, UE will obtain a soft symbol decision Wi foreach RLSi.

2. Combine the TPC from different RLSs and derive the TPC_cmd

UE derives TPC_cmd, it is based on a function and all the N softsymbol decisions Wi:TPC_cmd = (W 1, W 2, W N),Where TPC_cmd can only take the values 1 or -1.In Huawei implementation, the function shall fulfil the followingcriteria:If the TPCs from all RLSs are 1, the output of shall be equal to1;If one TPC from any RLS is 0, the output of shall be equal to -1.


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When UE is in soft handover state, multiple TPC will be received in each

slot from different cells in the active set. UE will generate the TPC_cmdby PCA2 as follows:1. Combine the TPC from the same RLS

When the RLs are in the same RLS, they will transmit the sameTPC in a slot. In this case, the TPCs from the same RLS shall becombined into one.

2. Calculate the TPC_temp i for each RLSUE derives TPC_temp i through the same way in the last slide, as

follows:

For the first 4 slots of a group, TPC_temp i = 0.For the 5th slot of a group:

If all 5 TPCs within a group are 1, then TPC_temp i = 1 inthe 5th slot;

If all 5 TPCs within a group are 0, then TPC_temp i = -1 inthe 5th slot;

Otherwise, TPC_temp i = 0 in the 5th slot.

3. Calculate the TPC_cmdUE derives TPC_cmd through the following criteria:

If any TPC_temp i is equal to -1, TPC_cmd is set to -1;

If , TPC_cmd = 1;

Otherwise, TPC_cmd = 0.

5.0 _ 1

1

N

iitempTPC N


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The example of the uplink inner loop PCA2 in soft handover state.


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PwrCtr lAlg

Content: This parameter is used to inform the UE of the methodfor translating the received Transmit Power Control (TPC)commands. In other words, it is used to select UL power controlalgorithm.Value range: ALGORITHM1, ALGORITHM2Physical value range: ALGORITHM1, ALGORITHM2Set this parameter through SET UFRC, query it through LSTUFRC, and modify it through SET UFRC.

UlTpcStepSize

Content: The step size of the closed loop power control performedon UL DPDCH. This parameter is mandatory when the parameterPwrCtrlAlg is set as ALGORITHM1.Value range: 1 to 2Physical value range: 1 to 2; step: 1Physical unit: dBSet this parameter through SET UFRC, query it through LSTUFRC, and modify it through SET UFRC.For PCA2, the step is fixed to 1 dB.


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Basically the downlink inner loop power control process is similar with

uplink, UE L3 sends SIR tar to UE L1 and then UE L1 compares SIR meawith SIR tar :If the SIR mea is greater than the SIR tar , UE sends TPC 0 toNodeB on uplink DPCCH TPC field;Otherwise, UE sends TPC 1 to NodeB.

The UE shall check the downlink power control mode before generatingthe TPC, two algorithm DPC_MODE1 and DPC_MODE2 could be usedby UE to derive the TPC. Upon receiving the TPC, NodeB shall estimatethe transmitted TPC and adjust its downlink DPCCH/DPDCH power

accordingly. After reception of one or more TPC in a slot, NodeB shall derive theestimated TPC TPC est (k) and calculate a P TPC (k), the power adjustmentof k:th slot.Then NodeB shall adjust the current downlink power P(k-1) to a newpower P(k), and adjust the power of the DPCCH and DPDCH with thesame amount, since power difference between them is fixed.


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The DPC_MODE parameter is a UE specific parameter and controlled by

the UTRAN.The UE shall check the DPC_MODE (Downlink Power Control Mode)before generating the TPC, and upon receiving the TPC, the UTRANshall adjust its downlink power accordingly.


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If PC_ DOWNLINK_POWER_BALANCE_SWITCH is OFF, then P bal (k)

equals 0.


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From the definition above, sum (k) indicates the sum of downlink power

adjustment in the latest DL_Power_Average_Window_Size time slots.Power_Raise_Limit is set to 10dB.DL_Power_Averaging_Window_Size is set to 20 slots.


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PC_INNER_LOOP_LMTED_PWR_INC_SWITCH

This is one switch in PcSwitch (Power control switch) parameter.Content: When the switch is on, the limited power increasefunction is used for DL inner loop power control.Value range: 1, 0Physical value range: ON, OFFSet this parameter through SET UCORRMALGOSWITCH, queryit through LST UCORRMALGOSWITCH, and modify it throughSET UCORRMALGOSWITCH.

FddTpcDlStepSize

Content: This parameter specifies the step size of the closed-looppower control performed on DL DPCH in Frequency DivisionDuplex (FDD) mode.Value range: STEPSIZE_0.5DB, STEPSIZE_1DB,STEPSIZE_1.5DB, STEPSIZE_2DBPhysical value range: 0.5, 1, 1.5, 2; step: 1Physical unit: dBSet this parameter through SET UFRC, query it through LSTUFRC, and modify it through SET UFRC.


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During soft handover, the UL TPC is demodulated in each RLS, then due

to demodulation errors, the DL transmit power of the each branch in softhandover will drift separately, which causes loss to the macro-diversitygain.The DL Power Balance (DPB) algorithm is introduced to reduce thepower drift between links during the soft handover.


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PC_DOWNLINK_POWER_BALANCE_SWITCH

This is one switch in PcSwitch (Power control switch) parameter.Content: When the switch is on, the RNC supports DL powerbalancing. During soft handover, TPC bit errors may cause DLpower drift. DL power balancing is enabled to balance the DLpower between links, thus achieving the optimal gain of softhandover.Value range: 1, 0Physical value range: ON, OFFSet this parameter through SET UCORRMALGOSWITCH, query

it through LST UCORRMALGOSWITCH, and modify it throughSET UCORRMALGOSWITCH.


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The main reason of outer loop power control:

The QoS which NAS provides to CN is BLER, not SIR.The relationship between inner loop power control and outer loop powercontrol:

SIRtar should be satisfied with the requirement of decodingcorrectly. But different multi-path radio environments requestdifferent SIRtar. Therefore, the outer loop power control canadjust the SIRtar to get a stable BLER in the changeable radioenvironment.


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Uplink outer-loop power control is performed in the SRNC. The SRNC

measures the received BLER and compares it with the BLER tar . If theBLER mea is greater than the BLER tar , the SRNC increases the SIR tar ;otherwise, the SRNC decreases the SIR tar .


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The initial SIR target value is transmitted to the NodeB by using NBAP

signaling of each RADIO LINK SETUP or RADIO LINKRECONFIGURATION PREPARE messages.


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According to the formula above,

SIR tar (n) is the target SIR used for the n:th adjustment period.MAX means the maximum value among the total i transmissionchannels.BLER meas,i (n) is measured for the i:th transmission channel in then:th adjustment period.BLER tar,i is the target BLER of the i:th transmission channel.Step i is the adjustment step of the i:th transmission channel.Factor is the adjustment factor.

In case of multi-service:The maximum value of the SIR target among multiple services isused for the SIR target adjustment.If one of the services requires increase in the SIR target, thereconfigured SIR target cannot exceed that maximum value.The maximum value can be decreased only when all the servicesrequire decrease in the SIR target.


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Where,

SIR tar is the adjustment of SIR tar , and SIR tar = SIR tar (n+1) -SIR tar (n).

ABS ( SIR tar ) means absolute value of SIR tar .


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Where,

CSD: CS domain Data service.I/B: Interactive and Background.

Set these parameter through ADD UTYPRABOLPC, query it through LSTUTYPRABOLPC, and modify it through MOD UTYPRABOLPC.


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P- 68

PC_OLPC_SWITCH

This is one switch in PcSwitch (Power control switch) parameter.Comments: When the switch is on, the RNC updates the UL SIRTARGET of radio links on the NodeB side through IUB DCH FPin-band signaling.Value range: 1, 0Physical value range: ON, OFFSet this parameter through SET UCORRMALGOSWITCH, queryit through LST UCORRMALGOSWITCH, and modify it throughSET UCORRMALGOSWITCH.


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Course Name


P- 69

In an optimal condition, the BER target is the average BER after filtering

within the adjustment period. The BER target is obtained before the DTXperiod starts during the outer-loop power control period. During softhandover, the BER target is the minimum value among all the links.When the BLER is a constant, the BER on the DPCCH can vary within alimited range.During the DTX, the MAC measures the BER on the DPCCH, and theRNC compares it with the BER target. If the measured BER is smallerthan the BER target, the OLPC decreases the SIR target. Otherwise, theOLPC increases the SIR target.


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Course Name


P- 70

The downlink outer loop power control is implemented inside the UE.

Therefore, this algorithm is specified by UE manufacturer.The information signaled to the UE by the RNC is a quality target foreach radio bearer, expressed as a BLER target. Then, depending on themanufacturer specific outer-loop power control algorithm, an initial SIRtarget value can be deduced from this BLER value.Generally, the UE L3 measures the received BLER and compares it withthe BLER tar . If the BLER mea is greater than the BLER tar , the L3 increasesthe SIR tar and send it to UE L1; otherwise, the L3 decreases the SIR tar .


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Course Name P- 71

3 WCDMA RAN12 Power Control Algorithm and Parameters ISSUE1.00

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