Power Control Analysis

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Copyright Huawei Technolog ies Co., Ltd. 2011. All rights reserved.

No part of this document may be reproduced or transmitted in any form or by any means without priorwritten consent of Huawei Technologies Co., Ltd.

Trademarks and Permissions

and other Huawei trademarks are trademarks of Huawei Technologies Co., Ltd.

All other trademarks and trade names mentioned in this document are the property of their respectiveholders.

Notice

The purchased products, services and features are stipulated by the commercial contract made betweenHuawei and the customer. All or partial products, services and features described in this document maynot be within the purchased scope or the usage scope. Unless otherwise agreed by the contract, allstatements, information, and recommendations in this document are provided "AS IS" without warranties,guarantees or representations of any kind, either express or implied.

The information in this document is subject to change without notice. Every effort has been made in the

preparation of this document to ensure accuracy of the contents, but all statements, information, andrecommendations in this document do not constitute the warranty of any kind, express or implied.

Issue 04 (2011-02-28) Huawei Proprietary and Confidential

Copyright Huawei Technologies Co.,

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7 Glossary ......................................................................................................................................7-18 Reference Documents .............................................................................................................8-1


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1 Introduction

1.1 Scope

This document describes the functions of and technologies regarding the Power Control feature ofHuawei GBSS, including Huawei II Power Control algorithm (PCII), Huawei III Power Control algorithm(PCIII), Optimized Huawei III Power Control algorithm (PCIII Opt.), Single Antenna InterferenceCancellation (SAIC) Power Control optimization, and active Power Control.

1.2 Intended Audience

It is assumed that users of this document are familiar with GSM basics and have a working knowledge ofGSM telecommunications.

This document is intended for:

Personnel working with Huawei GSM products or systems

System operators who need a general understanding of this feature

1.3 Change History

The change history provides information on the changes in the Power Control feature in differentdocument versions.

There are two types of changes, which are defined as follows:

Feature change: refers to the change in the Power Control feature of a specific product version.

Editorial change: refers to the change in wording or the addition of the information that was notdescribed in the earlier version.

Document IssuesThe document issues are as follows:

04 (2011-02-28)

03 (2011-01-10)

02 (2010-11-23)

01 (2010-06-30)

Draft (2010-03-30)

04 (2011-02-28)

This is the forth release of GBSS12.0.

Compared with issue 03 (2011-01-10) of GBSS12.0, this issue incorporates the changes described inthe following table.

Change Type Change Descrip tion Parameter Change

Featurechange

None None

Editorialchange

The contents in Table 4-31aremodified.

None


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03 (2011-01-10)

This is the third release of GBSS12.0.

Compared with issue 02 (2010-11-23) of GBSS12.0, this issue incorporates the changes described in

the following table.


Featurechange

None None

Editorialchange

The issue optimizes thedescription, and adds chapter4.3.1 Algorithm Selection.

None

02 (2010-11-23)

This is the second release of GBSS12.0.

Compared with issue 01 (2010-06-30) of GBSS12.0, this issue incorporates the changes described inthe following table.


Featurechange

None None

Editorialchange

The issue optimizes thedescription, and adds chapter 4"Engineering idelineGu ."

None

01 (2010-06-30)

This is the first release of GBSS12.0.

Compared with issue Draft (2010-03-30) of GBSS12.0, issue 01 (2010-06-30) of GBSS12.0 incorporatesthe changes described in the following table.


Featurechange

The power control level of 0.2dBis added.

A new parameter is added:FINESTEPPCALLOWED.

Editorialchange

Parameters are presented in theform of Parameter ID instead ofParameter Name.

None.

Draft (2010-03-30)

This is the draft release of GBSS12.0.


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MR Filtering

The PCII algorithm uses a sliding window filtering algorithm.

The PCIII and PCIII Opt. algorithm always uses both a sliding window and exponential filtering algorithm.

3.1.3 Power Control Algorithms

Huawei algorithms for Power Control consist of the PCII algorithm and the PCIII and PCIII Opt. algorithm,which have completely different approaches.

The PCII algorithm is a dual-threshold power control algorithm, with the following features:

MR compensation

Predictive filtering

Variable power control step for level

Fixed power control step of quality

Adjustment of the upper threshold of signal strength in the case of bad signal quality Separate configuration of the adjustment step for uplink and downlink power control

The PC III and PCIII Opt. algorithm is a single setpoint algorithm for level and quality, resulting in aproportional adjustment, additionally having the following functions:

Exponential filtering and sliding window filtering

Interpolation optimization

Comprehensive decision based on receive level and receive quality

Different thresholds for different speech rate types

3.1.4 Power Control Procedures

The uplink Power Control procedure involves three SACCH MR periods. In the first period, the BTSsends the MS a Power Control command message. In the second period, the MS performs the poweradjustment. In the third period, the MS notifies the BTS of the adjusted power. Fi re 3-2gu shows theuplink procedures for Power Control.

Figure 3-2 Uplink Power Control procedures


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Uplink Power Control takes three SACCH MR periods:

1. The first SACCH MR period

The BTS sends a power and TA adjustment command in the SACCH header. On receiving thecommand, the MS starts to perform Power Control in the second MR period.

2. The second SACCH MR period

The rate at which the MS can change its power level is limited by the standards to 16 dB per SACCHperiod.

If the power is adjusted by 16 dB or less, the change can be made one MR period (104 frames or 480ms) is required for the power adjustment process.

If the power is adjusted by more than 16 dB, two (or possibly even more) MR periods are required forthe power adjustment process.

The maximum rate for an MS to adjust its power is 2 dB every 13 frames or 60 ms. Even if a large change

(for example 14 dB) can be made in a single period, note that the change cannot be made all at once, the

power value use is increased in small steps inside the SACCH frame. This can affect the average values

reported in the MR describing the RXLEV and Quality from this SACCH frame.

3. The third SACCH MR period

The current transmit power, which is the power level of the last burst in the previous SACCH MRperiod, is saved and is reported to the BTS in the next MR on the uplink SACCH.

The downlink Power Control procedures involve only two SACCH MR periods. Fi re 3-3gu shows thedownlink procedures for Power Control.

Figure 3-3 Downlink Power Control procedures

PCADJPERIODcontrols the frequency that the power control cycle is executed, in units of MR periods.The default value is 3. A value greater than 3 leads to delayed performance of Power Control. A valuesmaller than 3 leads to more frequent performance of Power Control, which consumes more processingresources. It may enhance power control, but note that frequent power control combined with high adjustfactors may result in instability (oscillation).


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Because the MRs may be obtained by the BTS or MS at varying transmit power, the algorithm cancompensate the receive values to take account of the transmit power used. MR compensation iscontrolled by the parameter MRCOMPREG.

3. Discarding of MRs in the initial phase of connection

In the initial phase of connection, the algorithm does not perform Power Control until the connectionhas established and become stable.

The PCII algorithm discards the first four MRs.

4. MR filtering

The Power Control decision is based on filtered values derived from the incoming stream of MRs.

Huawei Power Control II uses a sliding window type filter that gives an output equal to the average ofthe last n values, where n is the length of the window. The filter length can be configuredindependently for level and quality. Uplink and downlink use parametersULLEVFILTLEN/DLLEVFILTLENand ULQUAFILTLEN/DLQUAFILTLEN.

Due to the delay between the Power Control decision and power adjustment, the (filtered)measurement report data does not accurately indicate real-time values. To minimize the effects of this,

a predictive compensation is applied, that extrapolates any trend in the historic MRs to estimate whatthe current value should be if there was no delay.

Generally, the interval between Power Control decision and power adjustment is three MRs for uplinkand two for downlink. The length of the look ahead prediction is specified byULPREDLEND/DLPREDLEND.

After filtering the interpolated and extrapolated (predicted) MRs, the algorithm makes a decision onPower Control.

The prediction filtering applies only to the receive level.

IfULPREDLEND/DLPREDLENDis 0, no extrapolation (prediction) is performed, so the algorithm is driven simply by theoutput from the filter.

If ULLEVFILTLEN/DLLEVFILTLENis less than 5, Mean-value filtering is applied; otherwise, predictive filtering (weightedfiltering for most recent MRs and Mean-value filtering for the older MRs) is applied.

3.2.2 Power Control Decision

In the PCII algorithm the Power Control decision takes into account both level and quality and upper andlower thresholds are set for both level and quality, uplink and downlink (ULSSHIGHTHRED,ULSSLOWTHREDandULQHIGHTHRED,ULQLOWTHREDand DLSSHIGHTHRED,DLSSLOWTHRED andDLQHIGHTHRED, DLQLOWTHRED). Figure 3-5 shows how the adjustment isderived given particular values for level and quality.


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Figure 3-5 Power adjustment

Receive Level

Receive Quality

UL/DL Qual.

Upper Threshold

UL/DL Qual.

Lower Threshold

UL/DL RX_LEV

Lower Threshold

UL/DL RX_LEV

Upper Threshold

0

7

0 6

MAX(AdjStep_Lev,

AdjStep_Qul)

AdjStep_QulNo Action

AdjStep_LevNo Action

MAX(AdjStep_L

ev,

AdjStep_Qul)

AdjStep_Lev

AdjStep_Qul

AdjStep_Lev

3

The Power Control decision in PCII algorithm involves the following stages:

1. Calculation of power adjustment step based on receive level (RxLev)

The power adjustment is constrained, if the transmitter is already on full power, it is not possible toincrease the power any more.

The calculation is the same for both uplink and downlink. Only uplink is shown in Figure 3-5.

When RxLev is less than the desired threshold ULSSLOWTHRED, the power should be increased,the formula is as follows:

power_adjustment_step = min {abs(0.5 x (ULSSHIGHTHRED+ ULSSLOWTHRED) RxLev),MaxValAdjrx}

When RxLev is less than ULSSHIGHTHRED,a threshold that defines a reasonable margin above thenoise floor, the power should not be decreased further.

In the PCII algorithm, receive quality is classified into three quality zones (low = 0, 1-2, 3). Themaximum step of power adjustment on uplink may be different for the three quality zones. These stepsare specified by MAXSTEP0, MAXSTEP1, and MAXSTEP2.

When the value of RxLev requires the power be decreased MAXSTEPx (x=0, 1, 2) step is selectedaccording to receive quality. The formula is as follows:

power_adjustment_step = min {abs (0.5 x (ULSSHIGHTHRED+ ULSSLOWTHRED) RxLev),MAXSTEPx}

2. Calculation of power adjustment step based on receive quality (RxQual)

When RxQual is greater than or equal to ULQLOWTHRED, the power should be increased. Theadjustment step is specified by MAXADJPCVAL.

The power can be increased only when (Rxlev + MAXADJPCVAL) ULSSHIGHTHRED


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When the quality is poor for a call (when RxQual is greater than or equal to ULQUALBADTRIG), thevalue of ULQUALBADUPLEVis increased for this cycle only.

When RxQual is less than ULQHIGHTHRED, the power should be decreased. The adjustment step isspecified by QUALSTEP.

The power can be decreased only when (RxLev QUALSTEP) ULSSLOWTHRED3. Calculation of power adjustment step based on both RxLev and RxQual

To ensure the stability of power adjustment, both AdjStep_Lev and AdjStep_Qual should be taken intoconsideration. If the RxLev decision considers that it is safe to reduce the power, the algorithm decidesto increase or decrease the power depending on the quality.

If the RxLev decision considers that it is not safe to reduce the power, the algorithm may increase thepower or leave it the same, but cannot decrease it further.

The procedures for Power Control for AMR calls is the same as that for non-AMR calls but different parameters areinvolved. For details, see AMR Power Control of the AMR feature.


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3.3 Huawei III Power Control Algorithm

This section describes the feature GBFD-117601 HUAWEI III Power Control Algorithm.

The PCIII algorithm involves MR interpolation, MR filtering, and calculation of adjustment step, as shownin Figure 3-6.

Figure 3-6 Procedures for Huawei III Power Control algorithm

3.3.1 Power Control Activation

Power Control can be activated or deactivated for AMR and non-AMR calls independently usingparametersAMRCALLPCALLOWEDandNONAMRCALLPCALLOWED. Calls that with Power Controldisabled use full power.

3.3.2 Measurement Report Handling

When the PCIII algorithm is applied, a fixed number of MRs are discarded during the initial access of theMS to the network to prevent the impact of inaccurate MRs on the algorithm. The number of discardedMRs is specified by SDMRCUTNUM(SDCCH) and TCHMRCUTNUM (TCH).

Active Power Control is enabled and the MRs are not discarded when parameter PWRBCDALLOWDis set to YES.

The MR processing in the PCIII algorithm involves the following stages:

1. MR interpolation

If RXLEV values are missing, a value is interpolated linearly.


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If RXQUAL values are missing, the missed value is replaced with a synthetically generated"worst possible" Quality (RXQUAL=7)

The value of MS/BTS transmit power missing from the MRs is not interpolated. In such a case,MR filtering is not affected, and Power Control procedure proceeds normally.

The interpolation is not performed in the case that the measurement results are lost. If the number of continuously lost MRs is greater than the value of MRMISSNUM, the Power

Control procedures stop. The procedures will resume when a new MR is received.

2. MR filtering

MR filtering in the PCIII algorithm involves exponential filtering and sliding window filtering.

In the process of calculation, receive quality is converted into C/I. In MR filtering, exponential filteringand sliding window filtering are performed on C/I and receive level in succession. The measurementvalue obtained through the filtering is used to decide whether Power Control is performed.

In the PCIII algorithm, the filtering periods are specified by the following parameters:

Uplink:

ULREXLEVEXPFLTLEN, ULREXQUALEXPFLTLEN, ULREXLEVSLDWINDOW, andULREXQUALSLDWINDOW

Downlink:

DLREXLEVEXPFLTLEN, DLREXQUALEXPFLTLEN, DLREXLEVSLDWINDOW, andDLREXQUALSLDWINDOW

3.3.3 Power Control Decision

Power Control decision in the PCIII algorithm involves the following stages:

If it is within the specified range, Power Control is performed.

The gain of the channels on the Um interface is obtained through calculation.

The adjustment step is calculated on the basis of the gain, RxLev, and RxQual after filtering.

The calculated step will be checked to determine whether it exceeds the maximum step allowed.

1. Decision on whether Power Control should be performed

Power Control is not required when ULREXLEVHIGHTHREDRxlev ULREXLEVLOWTHREDand UL**REXQUALHIGHTHRED RxQual UL**REXQUALLOWTHRED.

Otherwise, the calculation of the adjustment step starts.

In Huawei III Power Control algorithm, different quality level thresholds are set for different speech coding schemes.The symbol ** represents full-rate service (FS), half-rate service (HS), AMR full-rate service (AFS), or AMR half-rateservice (AHS).

2. Calculation of adjustment stepThe PCII algorithm is based on dual thresholds, and increases the power if the channel is below thelower threshold, and reduces the power if it is above the upper threshold.

The PCIII algorithm is quite different and is a P controller. That is to say the adjustment made issimply proportional to the difference (and "error") between a configured setpoint and the current(filtered) control metric.

The error is computed and scaled for both a level and quality term. That is, there is a level setpointand gain, and a quality setpoint and gain.

The controller computes the adjustment ("step") for each cycle and this is added to the precedingpower attenuation to give the power attenuation to be used in this cycle.


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Calculating the BTS Power Control Step

In each power control period, the power control adjustment step is calculated on the basis of the receivelevel and receive quality.

g(k) = p(k) (ca_filtered(k) + qa_filtered(k) 10 x log10 (1 + 10^( qa_filtered(k)/10)))

SThr = (SThrUp + SThrDown)/2

QThr = (QThrUp + QThrDown)/2

step(k) = (sfactor x (BsTxMaxPower g(k) SThr) + qfactor x (qa_filtered(k) QThr))

If step (k) > 0, step (k) = 0.

Where,

SthrUp: indicates downlinkreceivelevelupperthreshold that is specified by DLRexLevHighThred .

SThrDown: indicates downlinkreceivelevellower threshold that is specified by DLRexLevLowthred.

QThrUp =DL**RexQualHighThred

QthrDown = DL**RexQualLowThred

Sfactor = DLREXLEVADJFCTR

BsTxMaxPowe: the maximum transmit power of the TRX used for the call

Qfactor = DLREXQUALADJFCTR

g (k): gain of the radio channel (referred to as path loss of the channel)

qa_filtered (k): MR of the filtered receive quality (converted to CIR)

ca_filtered(k): MR of the filtered receive level

p(k): transmit power of the BTS

You can calculate the valid level through the CIR and the receive level (including the valid signals andthe interference signals), and then calculate the channel gain by distracting the valid level from thetransmit power.

To prevent excessive adjustment, control the range of step (k) by setting DLMAXUPSTEP orDLMAXDOWNSTEP. If the value of step (k) is greater than the maximum allowable step length, thepower is controlled according to the maximum allowed step set in this parameter. DLMAXUPSTEPindicates maximum step by which to increase downlink power according to signal strength.DLMAXDOWNSTEPindicates maximum step by which to decrease downlink power according to signal

strength.

Calculating the MS Power Control Step

In each power control period, the power control adjustment step is calculated on the basis of the receivelevel and receive quality.

g(k) = p(k) (ca_filtered(k) + qa_filtered(k) 10 x log10 (1 + 10^( qa_filtered(k)/10)))

SThr = (SThrUp + SThrDown)/2

QThr = (QThrUp + QThrDown)/2

step(k) = (sfactor x (MsTxMaxPower g(k) SThr) + qfactor x (qa_filtered(k) QThr))


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If step(k) > 0, step(k) = 0.

Where,

SthrUp: indicates uplinkreceivelevelupperthreshold that is specified by ULRexLevHighThred .

SThrDown: indicates uplinkreceivelevellower threshold that is specified by ULRexLevLowthred.

QThrUp = UL**RexQualHighThred

QThrDown = UL**RexQualLowThred

Sfactor = ULREXLEVADJFCTR

MsTxMaxPower: maximum transmit power in the MS classmark

Qfactor = ULREXQUALADJFCTR

g(k): gain of the radio channel (referred to as path loss of the channel)

qa_filtered (k): filtered receive quality (converted to CIR)

ca_filtered(k): MR of the filtered receive level

p(k): transmit power of the MS

To prevent excessive adjustment, control the range of step (k) by settingULMAXUPSTEP/ULMAXDOWNSTEP. If the value of step(k) is greater than the allowed maximum steplength, the power is controlled according to the maximum allowed step set in this parameter.

By default, the minimum power adjustment step is 2 dB, but some BTS products support higherresolution Power Control, in 0.2 dB steps. This provides enhanced performance. This is controlled byparameter FINESTEPPCALLOWED.


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3.4 Optimized Huawei III Power Control Algorithm

The process of the PCIII Opt. algorithm is the same as the process of the PCIII algorithm. The PCIII Opt.algorithm involves MR processing, MR filtering, calculation of the Power Control step, and Power Controlexecution. The PCIII Opt. algorithm takes effect when PWRCTRLSWis set to PWR3 (Power Control III)and PWRCTRLOPTIMIZEDENis set to YES.

This section describes the improvements of the PCIII Opt. algorithm over the PCIII algorithm.

3.4.1 Measure Report Handling

1. MR Power Control compensation

MR Power Control compensation aims to compensate the receive level and receive quality so thatthey reach the measured values at the maximum transmit power.

In the PCIII Opt. algorithm, the receive level and receive quality reported through the MR arecompensated. Subsequently, the receive level after compensation and the receive quality aftercompensation are used as inputs for MR filtering.

The formula for calculating the quality compensation value is as follows:

Quality compensation value = 2 x Power control level

The formula for calculating the level compensation value is as follows:

When the current CS session is carried on the BCCH TRX:

If frequency hopping (FH) is not used or the BCCH frequency is not involved in FH, the BSS does notcompensate for power control.

If the BCCH frequency is involved in FH and CANPC is set to YES, Level compensation value = 2 xPower control level; when the BCCH frequency is involved in FH and CANPC is set to NO, Levelcompensation value = (N-1)/N x Power control level x 2, where N is the number of frequenciesinvolved in FH.

When the current CS session is not carried on the BCCH TRX:

If the BCCH frequency is not involved in FH, Level compensation value = 2 x Power control level.

If the BCCH frequency is involved in FH and CANPC is set to YES, Level compensation value = 2 xPower control level; when the BCCH frequency is involved in FH and CANPC is set to NO, Levelcompensation value = (N-1)/N x Power control level x 2, where N is the number of frequenciesinvolved in FH.

If baseband FH is used and the BCCH frequency is involved, it is recommended that PCHOCMPCONbe set toON. Bydoing this, power control accuracy is improved. This also reduces the number of ping-pang handovers caused by theinconsistency between power control compensation and handover compensation.

2. Dual-coefficient MR filtering algorithm

The PCIII Opt. algorithm adopts an exponential filtering algorithm and MR filtering adopts thedual-coefficient filtering algorithm. The dual-coefficient filtering algorithm concerns the receive leveland the receive quality.

This algorithm has a strong correlation with the filtering period K and the filter adjustment factorFiltAdjustFactor.

The values of K and FiltAdjustFactor vary with the measured receive level and receive quality:

The value of Kdepends on ULREXLEVEXPFLTLEN/DLREXLEVEXPFLTLENandULREXQUALEXPFLTLEN/DLREXQUALEXPFLTLEN.

The value of FiltAdjustFactor, can be adjusted using parameter ULFILTADJFACTOR.


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In this section, the symbol / separates two independent parameters. For example,ULREXLEVEXPFLTLEN/DLREXLEVEXPFLTLENindicates ULREXLEVEXPFLTLENor DLREXLEVEXPFLTLEN.ULREXLEVEXPFLTLENand DLREXLEVEXPFLTLENtake effect in uplink Power Control and downlink Power Controlrespectively.

In the dual-coefficient exponential filtering algorithm, the filter response rate increases when the radiopropagation environment deteriorates. In this case, the filter length is K. The rate of increasing thefiltering value decreases when the radio propagation environment becomes better. In this case, the filterlength is K x FiltAdjustFactor.

3.4.2 Calculation of the Power Control Step

The Power Control step of the PCIII Opt. algorithm is calculated on the basis of two step factors:output1(k) and output2(k). The methods of calculating power control step are similar in the uplink anddownlink. This section uses the uplink as an example.

output1(k) is determined by RexLev_pf, RexQual_pf, STarget, and QTarget. The calculation formula is

as follows:output1(k) = - {RexLev_pf x (ca_filtered(k) - STarget) + RexQual_pf x(qa_filtered(k) - QTarget)}

Where,

RexLev_pf indicates ULRXLEVPROTECTFACTOR.

ca_filtered(k) indicates the measured receive level after the filtering.

STarget = ULREXLEVHIGHTHRED.

RexQual_pf = ULRXQUALPROTECTFACTOR.

qa_filtered(k) indicates the measured receive quality after the filtering.

QTarget = ULFSREXQUALHIGHTHRED .

output2(k) is determined by sfactor, qfactor, STarget, and QTarget. The calculation formula is as follows:

output2(k) = - {sfactor x (ca_filtered(k) - STarget) + qfactor x (qa_filtered(k) - QTarget)}

Where,

sfactor indicates RxLev Adjustment Factor ULREXLEVADJFCTR.

ca_filtered(k) indicates the measured receive level after the filtering.

STarget indicates RxLev setpoint, ULREXLEVHIGHTHRED.

qfactor indicates RxQual Adjustment Factor, ULREXQUALADJFCTR.

qa_filtered(k) indicates the measured receive quality after the filtering.

QTarget indicates RxQual setpoint, ULFSREXQUALHIGHTHRED .

The step factor output(k) is determined according to the formula

output(k) = max(output1(k), output2(k)).

Subsequently, based on this step factor, Power Control adjustment is performed. If output(k) is greaterthan 0, then output(k) is set equal to 0, that is, transmit power is not adjusted.

By default, the minimum power adjustment step is 2 dB, but some BTS products support higherresolution Power Control, in 0.2 dB steps. This provides enhanced performance. This is controlled byparameter FINESTEPPCALLOWED.


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3.5 Functions Related to Power Contro l

3.5.1 Active Power ControlThis section describes the feature GBFD-117602 Active Power Control.

Power Control is used to control the transmit power of the MS and BTS during a connection.For better results of Power Control, the MS and BTS should transmit signals at a proper powerinstead of the maximum power when the connection is initially established. To achieve this,Active Power Control must be enabled.

Active Power Control enables the immediate performance of Power Control after an MSsuccessfully gains access to the network or a handover is successfully performed in the BSC.In such a case, the BSC can control the uplink and downlink power promptly. Therefore, boththe BTS and the MS transmit signals at a proper power. Active Power Control aims to reduce

the system interference, improve the link quality, and decrease the power consumption of boththe BTS and MS.

Active Power Control is enabled when the parameter PWRBCDALLOWDis set to Yes.

Ac tive Power Control During the Access of an MS

The procedures for Active Power Control during the initial access of an MS are as follows:

1. The BSC acquires the uplink and downlink path loss on the basis of the receive level inthe MR of the MS on the signaling channel, transmit power of MS and BTS, andparameters DOUBLEANTENNAGAIN, COMBINERLOSS, and PATHLOSS. Based onwhether the BCCH and TCH belong to the same frequency band, the path loss of theuplink and downlink channels can be estimated as follows:

If the BCCH and TCH belong to the same frequency band (for example, both work inGSM850/GSM900 or DCS1800/PCS1900), then:

Path loss estimation of the uplink channel = Maximum transmit power of the MS in the cell Uplink receive level

Path loss estimation of the downlink channel = Transmit power of the BTS Downlinkreceive level +COMBINERLOSS+ DOUBLEANTENNAGAIN

If the BCCH and TCH belong to different frequency bands, then, a compensation for pathloss is necessary.

If the TRX of the TCH works on GSM850/GSM900 while the TRX of the BCCH works onDCS1800/PCS1900, then:

Path loss estimation of the uplink channel = Maximum transmit power of the MS in the cell Uplink receive level PATHLOSS

Path loss estimation of the downlink channel = Transmit power of the BTS Downlinkreceive level + COMBINERLOSS+ DOUBLEANTENNAGAIN PATHLOSS

If the TRX of the TCH works on DCS1800/PCS1900 while the TRX of the BCCH works onGSM850/GSM900, then:

Path loss estimation of the uplink channel = Maximum transmit power of the MS in the cell Uplink receive level + PATHLOSS

Path loss estimation of the downlink channel = Transmit power of the BTS Downlinkreceive level + COMBINERLOSS+ DOUBLEANTENNAGAIN+ PATHLOSS


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2. Based on the uplink and downlink path loss and the parameters EXPULRXLEV andEXPDLRXLEV, the BSC estimates the transmit power that the BTS and MS should adopton the assigned traffic channel.

3. The MS adopts the previously-mentioned power as the transmit power when it is initiallyassigned with a traffic channel, thereby reducing the initial transmit power.

Ac tive Power Control Dur ing Inner-BSC Handover

The procedures for active Power Control during inner-BSC handover are as follows:

1. The BSC acquires the uplink and downlink path loss on the basis of the level of the BCCHin the target cell, transmit power of MS and BTS, and value of PATHLOSS.

2. Based on the uplink and downlink path loss and the parameters EXPULRXLEV andEXPDLRXLEV, the BSC estimates the transmit power that the BTS and MS should adopton the channel of the target cell.

Uplink transmit power = EXPULRXLEV 110 dBm + Path loss estimation of the uplinkchannel

Downlink transmit power = EXPDLRXLEV 110 dBm + Path loss estimation of thedownlink channel

3. The MS adopts the previously-mentioned power as the transmit power when it gainsaccess to the target cell, thereby reducing the transmit power during the access.

3.5.2 SAIC Power Control Optimization

This section describes the feature GBFD-118103 Network Support SAIC.

Single Antenna Interference Cancellation (SAIC) is used to reduce the impact of interference

on the reception of downlink signals through a signal processing technology.

An MS enabled with SAIC has improved ability of anti-interference. After SAIC is enabled, thethresholds for BSC/BTS Power Control are adjusted to improve the radio performance of theBSS. SAIC is enabled when the parameters SAICALLOWEDand BTSSAICPCADJSWITCHare set to Yes. The policies for threshold adjustment are as follows:

When the PCII algorithm is applied, the value of SAICTHREDAPDTVALUE is added to thatof DLQHIGHTHREDand DLQLOWTHRED.

When the PCIII or PCIII Opt. algorithm is applied, the value of SAICTHREDAPDTVALUE isdeducted from that of UL**REXQUALHIGHTHRED/DL**REXQUALHIGHTHRED andUL**REXQUALLOWTHRED/DL**REXQUALLOWTHRED.

** indicates FS (full rate), HS (half rate), AFS (AMR full rate), or AHS (AMR half rate).


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4 Engineering Guideline

4.1 Overview

This section introduces common real world scenarios and gives guidance on the parameter setting tochoose for these varied environments.

4.2 Scenarios

Scenariosvaryfromonenetworktoanother. Themainscenariosareasfollows:

Table 4-1 Main scenarios

Appl ication Scenario Reference Value Feature Descr ip tion Effect on Parameters

Densely-populated urban

area

EFL=16

BTS spacing: 420 m

900 MHz

BCCH 1/12

TCH 1/3,

TCH pseudo random

hopping on 4 frequencies,

DTX on full-rate AMR V3

25M mast height Mobility

on, TU3

Huawei Handover II

To ensure large capacity

and indoor coverage, the

BTS spacing is small.

Thus, the outdoor level is

high and the overlapped

coverage areas are large.

Because the frequency

reuse is tight and the EFL

is high, the interference is

strong. This makes good

performance from power

control very important to

maximize quality

Power control: Generally,

power control should be

performed on the basis of

link quality such as BER.

Urban area EFL=14

BTS spacing: 1200 m

900 MHz

BCCH 1/12

TCH 1/3,

TCH pseudo random




on, TU3 Huawei Handover

II

To ensure large capacity

and indoor coverage, the

BTS spacing is small.

Thus, the outdoor level is

high and the overlapped

coverage areas are large.

Because the frequency

reuse is tight and the EFL

is high, the interference is

strong. This makes good

performance from power

control very important tomaximize quality




link quality such as BER.


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Suburb EFL=12

BTS spacing: 5300 m

900 MHz

BCCH 1/12TCH 1/3,

TCH pseudo random





II

Firstly, good coverage and

appropriate capacity

should be ensured for the

vicinity of the BTS.

Secondly, The coverage ofthe surrounding areas

should be as large as

possible. Therefore, the

coverage level is of great

importance. Generally, the

indoor-and-outdoor

cooperation policy is not

considered.

This scenario is regarded

as a coverage limitation

scenario.




RxLev and RxQual.

Rural area EFL=12

BTS spacing:15000 m

900 MHz

BCCH 1/12

TCH 1/12,

TCH pseudo random





II

The BTS spacing is large

and the capacity is small.

The coverage signal level

is the determinant factor.

The focus is to ensure

good network coverage.

Generally, the

indoor-and-outdoor

cooperation policy is not

considered.

Generally, this scenario is

not an interference

limitation one but a signal

level limitation one.




RxLev.

4.3 Key Parameters

4.3.1 Algori thm Selection

PWRCTRLSWand PWRCTRLOPTIMIZEDEN specify algorithm switchover.

PWRCTRLSWspecifies whether to enable PCII or PCIII algorithm. When PWRCTRLSWis set to PWR3,

Huawei PCIII algorithm is enabled.

PWRCTRLOPTIMIZEDENspecifies whether to enable the PCIII Opt. algorithm. When PWRCTRLSWisset to PWR3andPWRCTRLOPTIMIZEDENis set to YES, the PCIII Opt. algorithm is enabled.

Algorithm switchover involves PCII to PCIII, PCII to PCIII Opt., and PCIII to PCIII Opt. switchovers. Thedetailed commands are as follows:

PCII to PCIII switchover

To enable the PCIII algorithm, run the SET GCELLPWR3 command with PWRCTRLOPTIMIZEDENset to NO.

Run theSET GCELLPWRBASICcommand with PWRCTRLSWset to PWR3.

PCII to PCIII Opt.switchover


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To enable the PCIII Opt. algorithm, run the SET GCELLPWR3 command withPWRCTRLOPTIMIZEDEN set to YES.

Run the SET GCELLPWRBASIC command with PWRCTRLSWset to PWR3.

PCIII to PCIII Opt.switchover

To enable the PCIII algorithm, run the SET GCELLPWR3 command with PWRCTRLOPTIMIZEDENset to YES.

4.3.2 Common Parameters

The following parameters are used by more than one algorithm.

Measurement Report Type and Measurement Report Preprocessing:

The Enhanced Measurement Report supports the measurement of the 3G neighbor cells to enableinteroperability between 2G and 3G systems and therefore ensures service continuity. It also supportsmore information such as BER and FER. Normally, the Normal Measurement Report for the powercontrol and handover algorithms are used.

If the BSC load is very high or the Abis capacity is limited, processing in the BTS is advantageous to offload the BSC CPU, but this degrades handover performance slightly. It is recommended that operatorsreview the CPU load of the BSC and Abis capacity before deciding where processing should take place.If the load can support power control processing in BSC, processing in the BSC is preferred because thisallows improved handover performance.

If the BTS is used to process the measurement reports, the BTS decides the frequency at whichprocessed results are sent. During the process, certain MRs are missing and will affect HO performance.Therefore, operators must balance between CPU load and reduced accuracy in measurement historydue to missing MRs.

Table 4-2 Key parameters for MR processing

Parameter Name Value Range RecommendedValue

MEASURETYPEEnhMeasReport(Enhanced Measurement Report),ComMeasReport(Common Measurement Report)

ComMeasReport

BTSMESRPTPREPROCBSC_Preprocessing(BSC preprocessing),BTS_Preprocessing(BTS preprocessing)

BSC_Preprocessing

PRIMMESPPT NO, YES YES

BSMSPWRLEV NO, YES YES

MRPREPROCFREQ

NOreport(Do not report),Twice_ps(Twice every second),Once_ps(Once every second),Once_2s(Once every two second),Once_4s(Once every four second)

Twice_ps

4.3.3 Huawei II Power Control Parameters

1. Function Activation


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When PWRCTRLSWis set toPWR2, Huawei II Power Control algorithm is activated. Huaweirecommends the Optimized Huawei III Power Control algorithm. The parameters UPPCENandDNPCENcontrol whether to activate uplink power control and downlink power control for a cell.

Table 4-3 Function activation parameters

Parameter Name Value Range Recommended Value

PWRCTRLSW PWR2 (PCII), PWR3 (PCIII) PWR3

UPPCEN NO, YES YES

DNPCEN NO, YES YES

2. Period Control

PCADJPERIOD controls the minimum interval between two consecutive power control commands, If

this parameter is set to a too great value, effective power control may be delayed. If this parameter isset to a small value, Radio performance may be improved but more processing and Abis resources willbe consumed. Note that the PC value must be considered when setting the PC adjust factors, if a highadjust factor is combined with a high PC frequency (low value for PC interval) the power control maybecome unstable (oscillate)

Table 4-4 Period control parameters


PCADJPERIOD 1 to 15 3

AMRPCADJPERIOD 1 to 15 3

3. MR interpolation

MRMISSCOUNTdecides the number of measurement reports sampled for averaging the signalstrength on a speech/data channel. Averaging the signal strength in multiple measurement reportshelps to avoid a sharp signal level drop due to Rayleigh fading and to ensure the comprehensivenessof a handover decision. If this parameter value is too big, old MR information wont reflect the currentenvironment. If this parameter is too small, Power Control information will be re-initialized, which willdelay power control response time.

Table 4-5 Interpolation parameters


MRMISSCOUNT 0 to 31 4

4. MR compensation

The algorithm may receive the level and quality at different transmit powers, to ensure that correctreceive level values and receive quality values are used in filtering, compensation should be applied tothe receive level values and receive quality values in historical measurement reports obtained whentransmit power was different from the current value. MRCOMPREG controls whether the PCIIalgorithm allows measurement report compensation.


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Table 4-6 Compensation parameters


MRCOMPREG NO, YES YES

AMRMRCOMPREG NO, YES YES


No key parameter is related to this procedure.

6. MR filtering

The filtering parameters specify the number of measurement reports sampled for calculating theaverage value of the downlink signal strength before the BTS power adjustment. It is recommendedthat these parameters be set to 5 to balance between MR stability and response time. For high speed

scenarios these parameters should be reduced to improve response time, Huawei recommends 3.

Table 4-7 Filtering parameters for Non-AMR

Recommended ValueParameter Name Value Range

HighDensity

Urban Rural

ULLEVFILTLEN 1 to 20 3 5 5

DLLEVFILTLEN 1 to 20 3 5 5

ULQUAFILTLEN 1 to 20 3 5 5

DLQUAFILTLEN 1 to 20 3 5 5

Table 4-8 Filtering parameters for AMR


HighDensity

Urban Rural

AMRULLEVFTLEN 1 to 20 3 5 5

AMRDLLEVFTLEN 1 to 20 3 5 5

AMRULQUAFTLEN 1 to 20 3 5 5

AMRDLQUAFTLEN 1 to 20 3 5 5

7. Core Algorithm

Algori thm summary

The PCII algorithm divides the overall air interface quality into nine areas according to the receive leveland receive quality over the air interface. The nine areas are divided by upper and lower thresholds ofreceive quality and upper and lower thresholds of receive level. The air interface quality of a call isdetermined based on the measured values. Different adjustment directions and adjustment steps are

then selected for the nine areas. The objective of power control is to keep the receive level and receive


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quality at the optimum level (the central area in the following figure where no action is needed anymore).

Receive Level

Receive Quality

UL/DL Qual.

Upper Threshold

UL/DL Qual.Lower Threshold

UL/DL RX_LEV

Lower Threshold

UL/DL RX_LEV

Upper Threshold

0

7

0 6

MAX(AdjStep_Lev,

AdjStep_Qul)

AdjStep_QulNo Action

AdjStep_LevNo Action

MAX(AdjStep_L

ev,

AdjStep_Qul)

AdjStep_Lev

AdjStep_Qul

AdjStep_Lev

3

When the network quality deteriorates because of low level, the algorithm increases the transmissionpower of the MS or BTS. When network quality deteriorates due to high interference caused byincreased transmission power, the algorithm reduces the transmission power of the MS or BTS.

Table 4-9 Classification of the PCII algorithm threshold parameters (uplink)

No-AMR AMR

Upper threshold ULQHIGHTHRED AMRULQHTHREDQuality

Lower threshold ULQLOWTHRED AMRULQLOWTHRED

Upper threshold ULSSHIGHTHRED AMRULSSHTHREDLevel

Lower threshold ULSSLOWTHRED AMRULSSLTHRED

Table 4-10 Classification of the PCII algorithm threshold parameters (downlink)

No-AMR AMR

Upper threshold DLQHIGHTHRED AMRDLQHTHREDQuality

Lower threshold DLQLOWTHRED AMRDLQLTHRED

Upper threshold DLSSHIGHTHRED AMRDLSSHTHREDLevel

Lower threshold DLSSLOWTHRED AMRDLSSLTHRED


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Key issues for parameter setting

The parameter setting suggestion for different scenarios

The receive level threshold in interference-restricted scenarios (high density urban areas) should beset lower than that in common urban scenarios, whereas the receive level threshold incoverage-restricted scenarios (rural areas) should be set higher than that in common urban scenarios.

In high-speed scenarios, an increased margin should be provided to allow for more rapid changes inthe path loss due to mobility through the terrain. In such scenarios, therefore, the receive levelthreshold and receive quality threshold should be set to a bit higher than those in common scenarios.In addition, the power control filter length can be set to a lower value to enhance transient response ofthe algorithm.

The parameter setting suggestion for uplink and downlink

The receiver sensitivity of the BTS is higher than that of the MS, therefore the BTS receive level canbe lower than the MS receive level. In common urban scenarios it is recommended that the uplinkpower control threshold is set equal to or lower than the downlink power control threshold.

The parameter setting suggestion for AMR call and non-AMR call

AMR calls have better speech encoding/decoding capability than common calls, therefore the receivelevel threshold can be set to a lower value for AMR calls and the receive quality threshold to a higherlevel (worse) in order to reduce network interference. The PCII algorithm supports separate powercontrol threshold configurations for non-AMR calls and AMR calls.

The parameter setting suggestion for Upper and Lower threshold

If the difference between upper and lower receive levels and the difference between upper and lowerreceive quality are small, or if the adjustment step is scaled up or down too much within a powercontrol period, the algorithm may become unstable. The recommended separation between upper andlower receive levels is 8-18 dB.

Table 4-11 Parameter baseline for PCII core algorithm


ULSSHIGHTHRED 0 to 63 30

ULSSLOWTHRED 0 to 63 18

ULQHIGHTHRED 0 to 7 0

ULQLOWTHRED 0 to 7 3

DLSSHIGHTHRED 0 to 63 45

DLSSLOWTHRED 0 to 63 28

DLQHIGHTHRED 0 to 7 0

DLQLOWTHRED 0 to 7 2

AMRULSSHTHRED 0 to 63 30

AMRULSSLTHRED 0 to 63 18

AMRULQHTHRED 0 to 7 0

AMRULQLOWTHRED 0 to 7 3


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AMRDLSSHTHRED 0 to 63 33

AMRDLSSLTHRED 0 to 63 25

AMRDLQHTHRED 0 to 7 0

AMRDLQLTHRED 0 to 7 3

Table 4-12 Classification of the PCII algorithm protection parameters

PC Direction Control byLevel orQuality

Non-AMR Call AMR Call

By level MAXVALADJRX AMRMAXVALADJRXRaise power

By quality MAXADJPCVAL AMRMAXADJPCVAL

MAXSTEP0 AMRMAXSTEP0


By level


Decreasepower

By quality QUALSTEP AMRQUALSTEP

Table 4-13 Classification of the PCII algorithm bad quality threshold parameters

Direction Trigger Threshold orOffset

Non-AMR Calls AMR Calls

Threshold offset ULQUALBADUPLEV AMRULQUALBADUPLEVUplink

Trigger Threshold ULQUALBADTRIG AMRULQUALBADTRIG

Threshold offset DLQUALBADUPLEV AMRDLQUALBADUPLEVDownlink

Trigger Threshold DLQUALBADTRIG AMRDLQUALBADTRIG

No power control is conducted when the receive level is greater than UL/DL RX_LEV Upper Threshold

or AMR UL/DL RX_LEV Upper Threshold and receive quality is lower than UL/DL Qual Lower Thresholdor AMR UL/DL Qual. Lower Threshold. In this case, the areas without the need for power control can beminimized by setting the UL/DL Qual. Bad Trig Threshold or AMR UL/DL Qual. Bad Trig Threshold.

The UL/DL Qual. Bad Trig Threshold or AMR UL/DL Qual. Bad Trig Threshold increases the signalstrength upper threshold when the receive quality is poor. The parameters UL/DL Qual. Bad UpLEVDiffand AMR UL/DL Qual. Bad UpLEVDiff are used to increase the signal quality upper threshold scalewhen the receive quality is poor.

Table 4-14 Bad quality threshold improvement parameters


ULQUALBADTRIG 0 to 7 3


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Table 4-16 Function activation parameters



UPPCEN NO, YES YES

DNPCEN NO, YES YES

AMRCALLPCALLOWED OFF (Not Allowed), ON (Allowed) ON

NONAMRCALLPCALLOWED OFF (Not Allowed), ON (Allowed) ON

2. 0.2dB Power Control

Parameter FINESTEPPCALLOWEDactivates 0.2 dB downlink power control. This power control

function improves the power control precision.Table 4-17 Function activation parameter for 0.2dB Power Control


FINESTEPPCALLOWED NO, YES NO

3. Period Control

ULADJPRD andDLADJPRD control the minimum interval between two consecutive uplink powercontrol commands. If the value of this parameter is decreased, the reaction speed of power control

accelerates, but the signaling traffic on the Abis interface increases.

Table 4-18 Period control parameters


ULADJPRD 0 to 255 3

DLADJPRD 0 to 255 3

4. MR interpolation

If MRs are discarded when being transmitted over links, the PCIII algorithm interpolates new MRsusing an algorithm based on the worst estimation to compensate for discarded MRs. If excessive MRsare discarded, interpolated MRs cannot accurately reflect the radio environment. When the number ofdiscarded MRs exceeds a threshold, the power control process is re-initialized.

Table 4-19 Interpolation parameters


MRMISSNUM 1 to 255 5

5. MR compensation


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N/A


The MRs generated in the initial phase of connection must be discarded because of their low accuracy.

The discarded MRs do not participate in filtering. The following parameters specify the number of MRsdiscarded from the SDCCH and TCH the initial phase of connection.

Table 4-20 Initial stabilization period parameters


SDMRCUTNUM 0 to 5 1

TCHMRCUTNUM 0 to 10 3

7. MR filtering

The PCIII algorithm uses exponential filtering and sliding window filtering algorithms. Exponentialfiltering is performed on MRs before sliding window filtering.

The exponential filtering algorithm has the following characteristics: The longer the filtering algorithm is,the more stable power control is, but the slower the power control response is. In high-density urbanscenarios, the length of the exponential filtering algorithm should be reduced to ensure a more positiveresponse to door slam and corner scenarios.

Table 4-21 Filtering parameters for exponential filtering algorithm


High Urban Rural

DLREXLEVEXPFLTLEN 0 to 19 3 3 3

DLREXQUALEXPFLTLEN 0 to 19 3 3 3

ULREXLEVEXPFLTLEN 0 to 19 3 3 3

ULREXQUALEXPFLTLEN 0 to 19 3 3 3

The total effect of the filter in PCIII is determined by the sliding window and exponential components.Using a heavy filter length for both components will result in very heavy filtering which will degrade theperformance of power control. The recommended tuning is to use a moderate filter length for the

exponential component and set the sliding window to 1 (which effectively disables the sliding windowfilter).

Table 4-22 Filtering parameters for sliding window filtering algorithm


DLREXLEVSLDWINDOW 1 to 20 1

DLREXQUALSLDWINDOW 1 to 20 1

ULREXLEVSLDWINDOW 1 to 20 1

ULREXQUALSLDWINDOW 1 to 20 1


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8. Core Algorithm

Algori thm summary

The PCIII algorithm calculates the power control step based on two aspects: RX level and RX quality.The level factor and quality factor are used to control the balance between level adjustment andquality adjustment. The level threshold and quality threshold are used to control the step of level andquality adjustment.

Table 4-23 Classification of the PCIII algorithm parameters (uplink)

Factor or Threshold Normal Call AMR Call

Level Factor ULREXLEVADJFCTR

Quality Factor ULREXQUALADJFCTR

ULFSREXQUALHIGHTHRED

ULAFSREXQUALHIGHTHRED

Upper threshold

ULHSREXQUALHIGHTHRED

ULAHSREXQUALHIGHTHRED

ULFSREXQUALLOWTHRED

ULAFSREXQUALLOWTHRED

Lower threshold

ULHSREXQUALLOWTHRED

ULAHSREXQUALLOWTHRED

Upper threshold ULREXLEVHIGHTHRED

N/A

Lower threshold ULREXLEVLOWTHRED

N/A

Table 4-24 Classification of the PCIII algorithm parameters (downlink)

Factor or Threshold Normal Call AMR Call

Level Factor DLREXLEVADJFCTR

Quality Factor DLREXQUALADJFCTR

DLAFSREXQUALHIGHTHRED

Upper threshold DLFSREXQUALHIGHTHREDDLHSREXQUALHIGHTHRED DLAHSREXQUALHIGHTHR

ED

DLFSREXQUALLOWTHRED

DLAFSREXQUALLOWTHRED

Lower threshold

DLHSREXQUALLOWTHRED

DLAHSREXQUALLOWTHRED

Upper threshold DLREXLEVHIGHTHRED

N/A


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Lower threshold DLREXLEVLOWTHRED

N/A

Key issues for parameter setting

The relationships between the level factor and the quality factor

Value comparison between the quality factor and the level factor

Since fluctuation of RX quality is usually smaller than fluctuation of the RX level, the quality factor isusually set to a value bigger than the level factor, which increases quality change caused by powercontrol to balance the quality adjustment and level adjustment.

The sum of the quality factor and level factor is not always 1. If the sum is significantly greater than 1this can lead to instability in the power control algorithm.

Power control amplitude is also determined by the sum of the quality factor and level factor, which canbe increased to reduce the power consumption when signals are of high level and quality.

Different quality thresholds between different voice codec algorithms

Calls using different voice codec algorithms can be configured with different power control qualitythresholds since the decoding capability varies with the different voice codec algorithms. Calls usingan algorithm (for example AMR FR) with a high decoding capability can be configured with an RXquality threshold lower than the calls using an algorithm (for example HR) with a low decodingcapability. This ensures satisfaction of users performing HR calls and moderately reduces the voicequality of AMR FR calls. Network interference is decreased in this way.

Comparison between dual thresholds and a single threshold

The PCIII algorithm uses a single threshold, numerically equal to the median of the upper and lowerthreshold parameters. It is recommended that the upper and lower thresholds be set to the samevalue.

Adjustment strategies for different scenarios

Scenarios with high interference

In scenarios with high interference (for example urban areas), the quality factor can be increased andthe RX level threshold can be decreased moderately.

Scenarios with a challenge in providing necessary coverage

In scenarios where the coverage is insufficient, the level factor and RX level threshold can beincreased moderately.

High-density urban scenarios

High-density scenarios require faster response to changing conditions especially when increasingtransmission power in response to measured poor quality. The filter can be set to a shorted length,

also it can be useful to increase the thresholds moderately to increase the link margin.

Parameter tuning and scenarios

The PCIII algorithm is mainly concerned with the following parameters: RX quality threshold (varies byservice type), RX level threshold, quality factor, and level factor. It also takes into account otherparameters for example the filtering algorithm length and adjustment factors, which are usually set todefault values. The parameters which are different in the various scenarios shown here are emphasized.

Table 4-25 Parameter baseline for PCIII core algorithm

Parameter Name SuburbanScenario

UrbanScenario

Dense-UrbanScenario

High-SpeedScenario

DLREXLEVADJFCTR 4 3 3 3


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Parameter Name Suburban Urban Dense-Urban High-SpeedScenario Scenario Scenario Scenario

DLREXQUALADJFCTR 6 6 6 6

DLREXLEVHIGHTHRED 22 20 18 25

DLREXLEVLOWTHRED 22 20 18 25

DLFSREXQUALHIGHTHRED 16 16 16 18

DLFSREXQUALLOWTHRED 16 16 16 18

DLHSREXQUALHIGHTHRED 18 18 18 20

DLHSREXQUALLOWTHRED 18 18 18 20

DLAFSREXQUALHIGHTHRED 14 14 14 16

DLAFSREXQUALLOWTHRED 14 14 14 16

DLAHSREXQUALHIGHTHRED 16 16 16 18

DLAHSREXQUALLOWTHRED 16 16 16 18

DLMAXDOWNSTEP 6 6 6 6

DLMAXUPSTEP 8 8 8 8

DLREXLEVEXPFLTLEN 3 3 3 3

DLREXQUALEXPFLTLEN 3 3 3 3

ULREXLEVEXPFLTLEN 3 3 3 3ULREXQUALEXPFLTLEN 3 3 3 3

ULREXLEVSLDWINDOW 1 1 1 1

ULREXQUALSLDWINDOW 1 1 1 1

DLREXLEVSLDWINDOW 1 1 1 1

DLREXQUALSLDWINDOW 1 1 1 1

ULREXLEVADJFCTR 4 3 3 3

ULREXQUALADJFCTR 6 6 6 6

ULREXLEVHIGHTHRED 20 18 16 23

ULREXLEVLOWTHRED 20 18 16 23

ULFSREXQUALHIGHTHRED 16 16 16 18

ULFSREXQUALLOWTHRED 16 16 16 18

ULHSREXQUALHIGHTHRED 18 18 18 20

ULHSREXQUALLOWTHRED 18 18 18 20

ULAFSREXQUALHIGHTHRED 14 14 14 16


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Parameter Name Suburban Urban Dense-Urban High-SpeedScenario Scenario Scenario Scenario

ULAFSREXQUALLOWTHRED 14 14 14 16

ULAHSREXQUALHIGHTHRED 16 16 16 18

ULAHSREXQUALLOWTHRED 16 16 16 18

ULMAXDOWNSTEP 6 6 6 6

ULMAXUPSTEP 8 8 8 8

4.3.5 Optimized Huawei III Power Control Parameters

Optimized Huawei III Power Control algorithm is basically the same as the PCIII algorithm in procedures

such as MR processing, filtering, calculation of power control step, and power control execution. Theoptimization of PCIII algorithm is achieved from the following aspects:

The receive level and receive quality are compensated for the power control.

In the PCIII Opt. algorithm, measurements are filtered in exponential non-linear filters in order toeliminate variations of temporary disturbances.

In the PCIII Opt. algorithm, the calculation of power control step adopts dual factors to protect theareas with weak level.

The formula for calculating the power control step is optimized.


Huawei III power control optimized algorithm takes effect when PWRCTRLSWis set to PWR3andPWRCTRLOPTIMIZEDENis set to YES.

Table 4-26 Parameters baseline for PCIII core algorithm



AMRCALLPCALLOWED OFF(Not Allowed), ON(Allowed) ON

NONAMRCALLPCALLOWED OFF(Not Allowed), ON(Allowed) ON

UPPCEN [No,Yes] Yes

DNPCEN [No,Yes] Yes

PWRCTRLOPTIMIZEDEN NO(No), YES(Yes) YES

2. Core Algorithm

The parameter system of the PCIII Opt. algorithm

The Optimized Huawei III Power Control Algorithm is mostly the same as the PCIII algorithm in theoryand parameters. So the PCIII Opt. algorithm has the same parameters as PCIII plus some newparameters.


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Table 4-27 Parameters baseline for PCIII Opt. core algorithm

Parameter Name High Urban Rural

DLREXLEVADJFCTR 3 3 3

DLREXQUALADJFCTR 4 4 4

DLREXLEVHIGHTHRED 20 22 25

DLREXLEVLOWTHRED 20 22 25

DLFSREXQUALHIGHTHRED 18 18 18

DLFSREXQUALLOWTHRED 18 18 18

DLHSREXQUALHIGHTHRED 17 17 17

DLHSREXQUALLOWTHRED 17 17 17

DLAFSREXQUALHIGHTHRED 18 18 18

DLAFSREXQUALLOWTHRED 18 18 18

DLAHSREXQUALHIGHTHRED 18 18 18

DLAHSREXQUALLOWTHRED 18 18 18

DLMAXDOWNSTEP 30 30 30

DLMAXUPSTEP 30 30 30

ULREXLEVADJFCTR 3 3 3

ULREXQUALADJFCTR 4 4 4

ULREXLEVHIGHTHRED 20 22 25

ULREXLEVLOWTHRED 20 22 25

ULFSREXQUALHIGHTHRED 16 16 16

ULFSREXQUALLOWTHRED 16 16 16

ULHSREXQUALHIGHTHRED 16 16 16

ULHSREXQUALLOWTHRED 16 16 16

ULAFSREXQUALHIGHTHRED 15 15 15ULAFSREXQUALLOWTHRED 15 15 15

ULAHSREXQUALHIGHTHRED 16 16 16

ULAHSREXQUALLOWTHRED 16 16 16

ULMAXDOWNSTEP 30 30 30

ULMAXUPSTEP 30 30 30

ULFILTADJFACTOR 3 3 3

DLFILTADJFACTOR 3 3 3


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Parameter Name High Urban Rural

ULRXLEVPROTECTFACTOR 30 30 30

ULRXQUALPROTECTFACTOR 75 75 75

DLRXLEVPROTECTFACTOR 20 20 20

DLRXQUALPROTECTFACTOR 60 60 60

4.3.6 Active Power Control Parameters

1. Function activation

If PWRBCDALLOWD is set to YES, then during the initial access assignment or intra-BSC handover,the power forecast is performed when the traffic channels are activated. The forecast initial power is sent

to the BTS through the channel activation message, which enables the MS and BTS to transmit withappropriate power. Otherwise, the power forecast is not performed and the MS and BTS transmit withmaximum power.

Table 4-28 Function activation parameters of active power control


PWRBCDALLOWD NO, YES NO

UPPCEN NO, YES YES

DNPCEN NO, YES YES

2. Core Algorithm

Table 4-29 Key parameters for active power control algorithm


COMBINERLOSS 0 to 100 45

DOUBLEANTENNAGAIN 0 to 255 30

PATHLOSS 0 to 255 79

EXPDLRXLEV 0 to 63 30EXPULRXLEV 0 to 63 30

4.3.7 SAIC Power Control Parameters


The setting of parameter SAICALLOWEDdetermines whether an MS supports the SAIC function. SingleAntenna Interference Cancellation (SAIC) is used to reduce the impact of interference on the receptionof downlink signals through a signal processing technology. An MS enabled with SAIC has improved

ability of anti-interference. After SAIC is enabled, the thresholds for BTS/MS Power Control are adjustedto improve the radio performance of the BSS.


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Table 4-30 Function activation parameters of SAIC power control


SAICALLOWED NO, YES YES

2. Core Algorithm

Table 4-31 Key parameters for SAIC power control algorithm

Parameter name Value Range Recommended Value Remark

SAICTHREDAPDTVALUE0 to 2 1 This parameter is used in

power control algorithm II.

BTSSAICPCADJSWITCH OFF, ON OFF -

SAICTHREDAPDTVALUE 0 to 4 3 This parameter is used inpower control algorithm III.

4.4 Little Used Parameters

The following parameters are provided to allow system flexibility. It is recommended that operators usethe default values under normal conditions.

AMRSADLUPGRADE

ULPREDLEND

DLPREDLENDAMRULPREDLEND

AMRDLPREDLEND

BTSPWRNUM

AMRBTSPWRNUM


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5 Parameters

Table 5-1 Parameter description

Parameter ID NE MML Command Description

BTSMESRPTPREPROC

BSC6900 SETGCELLHOCTRL(Optional)

Meaning: Whether to enable the BTS topreprocess measurement reports. Thisparameter determines where to conduct powercontrol.

GUI Value Range: BSC_Preprocessing(BSCpreprocessing), BTS_Preprocessing(BTSpreprocessing)Actual Value Range: BSC_Preprocessing,BTS_PreprocessingUnit: NoneDefault Value: BSC_Preprocessing

PRIMMESPPT BSC6900 SETGCELLHOCTRL(Optional)

Meaning: Whether the BTSs send the originalmeasurement reports to the BSC afterpre-processing them. When this parameter is setto YES, the BTSs send the original andpre-processed measurement reports to the BSC.GUI Value Range: NO(No), YES(Yes)Actual Value Range: NO, YESUnit: NoneDefault Value: NO

BSMSPWRLEV BSC6900 SETGCELLHOCTRL(Optional)

Meaning: Whether to enable the BTS to transferBTS/MS power class to the BSC

GUI Value Range: NO(No), YES(Yes)Actual Value Range: NO, YESUnit: NoneDefault Value: YES

MRPREPROCFREQ

BSC6900 SETGCELLHOCTRL(Optional)

Meaning: Frequency at which the BTSs submitpre-processed measurement reports to the BSC

GUI Value Range: NOreport(Do not report),Twice_ps(Twice every second), Once_ps(Onceevery second), Once_2s(Once every twosecond), Once_4s(Once every four second)Actual Value Range: NOreport, Twice_ps,Once_ps, Once_2s, Once_4sUnit: NoneDefault Value: Once_ps


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MEASURETYPE BSC6900 SETGCELLCCUTRANSYS(Optional)

Meaning: Type of the measurement report (MR)reported by the MS

GUI Value Range: EnhMeasReport(Enhanced

Measurement Report),ComMeasReport(Common MeasurementReport)Actual Value Range: EnhMeasReport,ComMeasReportUnit: NoneDefault Value: ComMeasReport

PCADJPERIOD BSC6900 SETGCELLPWRBASIC(Optional)

Meaning: Minimum interval between twoconsecutive power control commands

GUI Value Range: 1~15Actual Value Range: TCH:480~7200, step:480;

SDCCH:470~7050, step:470Unit: msDefault Value: 3

MRMISSCOUNT BSC6900 SETGCELLHOFITPEN(Optional)

Meaning: If the number of measurement reportslost consecutively is no larger than this value,linear interpolation is performed for the values inthe lost measurement reports based on thevalues in the two measurement reports precedingand following the lost measurement reports.Otherwise, the lost measurement reports will bediscarded, and the value will be recalculatedwhen new measurement reports arrive.

GUI Value Range: 0~31Actual Value Range: 0~31Unit: NoneDefault Value: 4

ULLEVFILTLEN BSC6900 SETGCELLPWR2(Optional)

Meaning: When the network receivesmeasurement reports, in consideration of theaccuracy of a single measurement report, themeasurement values in certain measurementreports are filtered to represent the radiooperating environment. This parameter specifies

the number of measurement reports sampled forfiltering the uplink signal strength.

GUI Value Range: 1~20Actual Value Range: TCH:480~9600, step:480;SDCCH:470~9400, step:470Unit: msDefault Value: 5


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DLLEVFILTLEN BSC6900 SETGCELLPWR2(Optional)

Meaning: Number of measurement reportssampled for averaging downlink signal strength.A single measurement report may not reflect theactual network situations accurately. Therefore,

the BSC needs to average the measured valuesin several successive measurement reports toreflect the radio environment.


ULQUAFILTLEN BSC6900 SETGCELLPWR2(Optional)

Meaning: When the network receivesmeasurement reports, the measurement valuesin several straight measurement reports are

filtered to reflect the radio operating environmentfor the sake of accuracy. This parameterspecifies the number of measurement reportssampled for filtering the uplink signal quality.


DLQUAFILTLEN BSC6900 SETGCELLPWR2(Optiona

l)

Meaning: Number of measurement reportssampled for averaging downlink signal quality. A

single measurement report may not reflect theactual network situations accurately. Therefore,the BSC needs to average the measured valuesin several successive measurement reports toreflect the radio environment.



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ULPREDLEND BSC6900 SETGCELLPWR2(Optional)

Meaning: After the BSC delivers the powercontrol command, it should wait for a certainperiod before affirming the effect of the powercontrol. Therefore, the MR that power control

decision is based on cannot accurately reflect theradio environment during the power adjustment,but misses the latest changes of the receive leveland receive quality of the MS. Thus, the poweradjustment is delayed.To compensate the delay of power adjustment,the power control algorithm implements theprediction and filtering function. In other words,the BSC samples several uplink measurementreports, performs weighted filtering, and predictsN measurement reports from the current timeonwards in a short period.This parameter determines the number of uplink

measurement reports predicted by the BSC. Inother words, the value of this parameter equals tothe previous number N.


DLPREDLEND BSC6900 SETGCELLPWR2(Optional)

Meaning: Number of downlink measurementreports that the BSC predicts. The BSC takes awhile to confirm the power control effect of a

power control command. Thus, the BSC makes apower control decision based on a measurementreport that lags behind the changes in the receivelevel and quality instead of reflecting the real-timeradio environment. As a result, the power controlis late.To prevent late power control to a certain degree,the power control algorithm involves ameasurement report prediction filter. The BSCcan sample several downlink measurementreports in a short time and then weigh them topredict future N measurement reports.This parameter specifies the number N.


ULSSHIGHTHRED

BSC6900 SETGCELLPWRBASIC(Optional)

Meaning: When the uplink receive level reachesthe threshold, Huawei II power control isperformed.

GUI Value Range: 0~63Actual Value Range: 0~63

Unit: dB


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Default Value: 30

ULSSLOWTHRED BSC6900 SETGCELLPWRBASIC(Optional)

Meaning: When the uplink receive level is belowthe threshold, Huawei II power control isperformed.

GUI Value Range: 0~63Actual Value Range: 0~63Unit: dBDefault Value: 18

ULQHIGHTHRED BSC6900 SET

GCELLPWRBASIC(Optional)

Meaning: The MS transmit power is decreased

only when the quality level of the MS transmitsignal is smaller than the value of the parameter.If (the uplink receive level - MAX Up Adj. PCValue by Qual) is smaller than "UL RX_LEVLower Threshold", the MS transmit power is notadjusted.


ULQLOWTHRED BSC6900 SETGCELLPWRBASIC(Optional)

Meaning: The MS transmit power is increasedonly when the quality level of the MS transmitsignal is greater than the value of the parameter.If (the uplink receive level + MAX Up Adj. PCValue by Qual) is greater than "UL RX_LEVUpper Threshold", the MS transmit power is notadjusted.



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DLSSHIGHTHRED


Meaning: Upper threshold for downlink signalstrengthIf the downlink received signal level is greaterthan this threshold, a power decrease is

computed. Then, the power is decreased by theleast of the power decrease, maximum poweradjustment step allowed by the quality zone towhich the received signal quality belongs, and"MAX Down Adj. PC Value by Qual.".Power decrease = downlink received signal level- ("DL RX_LEV Upper Threshold" + "AMR DLRX_LEV Lower Threshold")/2The maximum power adjustment step allowed bythe quality zone is chosen from "MAX DownAdj.Value Qual.Zone 0", "MAX Down Adj.ValueQual.Zone 1", and "MAX Down Adj.ValueQual.Zone 2" according to the quality zone.


DLSSLOWTHRED BSC6900 SETGCELLPWRBASIC(Optional)

Meaning: Lower threshold for downlink signalstrengthIf the downlink received signal level is less thanthis threshold, a power increase is computed.Then, the power is increased by the least of thepower increase, "MAX Up Adj. PC Value by

RX_LEV", and "MAX Up Adj. PC Value by Qual.".Power increase = ("DL RX_LEV UpperThreshold" + "AMR DL RX_LEV LowerThreshold")/2 - downlink received signal level


DLQHIGHTHRED BSC6900 SETGCELLPWRBASIC(Optional)

Meaning: Quality level threshold for decreasingdownlink signal power. If the BTS transmitssignals at a quality level less than this threshold,

the BSC decreases the power of the BTS. If(downlink receive level - "MAX Down Adj. PCValue by Qual.") < "DL RX_LEV LowerThreshold", the BSC does not adjust the transmitpower.



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DLQLOWTHRED BSC6900 SETGCELLPWRBASIC(Optional)

Meaning: Quality level threshold for increasingdownlink signal power. If the BTS transmitssignals at a quality level greater than thisthreshold, the BSC increases the power of the

BTS. If (downlink receive level + "MAX Up Adj.PC Value by Qual.") > "DL RX_LEV UpperThreshold", the BSC does not adjust the transmitpower.


MAXSTEP0 BSC6900 SETGCELLPWR2(Optional)

Meaning: Huawei power control algorithm IIdivides three quality zones according to thequality of the receive signals. When the power is

downwardly adjusted according to the level, themaximum downward adjustment step can varyaccording to the quality of the received signals.This parameter specifies the maximum step ofdownward power adjustment when the quality ofthe received signals falls into quality zone 0.


MAXSTEP1 BSC6900 SET

GCELLPWR2(Optional)

Meaning: Huawei power control algorithm II

divides three quality zones according to thequality of the receive signals. When the power isdownwardly adjusted according to the level, themaximum downward adjustment step can varyaccording to the quality of the received signals.This parameter specifies the maximum step ofdownward power adjustment when the quality ofthe received signals falls into quality zone 1.

GUI Value Range: 0~30Actual Value Range: 0~30Unit: dB

Default Value: 0


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MAXSTEP2 BSC6900 SETGCELLPWR2(Optional)

Meaning: Huawei power control algorithm IIdivides three quality zones according to thequality of the receive signals. When the power isdownwardly adjusted according to the level, the

maximum downward adjustment step can varyaccording to the quality of the received signals.This parameter specifies the maximum step ofdownward power adjustment when the quality ofthe received signals falls into quality zone 2.


MAXADJPCVAL BSC6900 SETGCELLPWR2(Optiona

l)

Meaning: Step of upward power adjustmentaccording to the quality of the received signals


ULQUALBADTRIG BSC6900 SETGCELLPWR2(Optional)

Meaning: In the case of power control, when theuplink receive quality is not smaller than "ULQual. Bad Trig Threshold", the actual "ULRX_LEV Upper Threshold" is increased by "ULQual. Bad UpLEVDiff".

GUI Value Range: 0~7

Actual Value Range: 0~7Unit: NoneDefault Value: 3

ULQUALBADUPLEV

BSC6900 SETGCELLPWR2(Optional)

Meaning: In the case of power control, when theuplink receive quality is not smaller than "ULQual. Bad Trig Threshold", the actual "ULRX_LEV Upper Threshold" is increased by "ULQual. Bad UpLEVDiff".

GUI Value Range: 0~63Actual Value Range: 0~63

Unit: dBDefault Value: 5

QUALSTEP BSC6900 SETGCELLPWR2(Optional)

Meaning: Step of downward power adjustmentaccording to the quality of the received signals



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AMRCALLPCALLOWED


Meaning: Whether to enable the III power controlalgorithm for AMR calls. If enabled, power controlis performed on AMR calls.

GUI Value Range: OFF(Not Allowed),ON(Allowed)Actual Value Range: OFF, ONUnit: NoneDefault Value: ON

NONAMRCALLPCALLOWED


Meaning: Whether to enable the III power controlalgorithm for Non-AMR calls. If enabled, powercontrol is performed on Non-AMR calls.

GUI Value Range: OFF(Not Allowed),ON(Allowed)Actual Value Range: OFF, ON

Unit: NoneDefault Value: ON

SDMRCUTNUM BSC6900 SETGCELLPWR3(Optional)

Meaning: Maximum number of discarded MRsallowed on the SDCCH in a power control period.GUI Value Range: 0~5Actual Value Range: 0~5Unit: NoneDefault Value: 1

TCHMRCUTNUM BSC6900 SETGCELLPWR3(Optiona

l)

Meaning: Maximum number of discarded MRsallowed on the TCH in a power control period.


PWRBCDALLOWD


Meaning: Whether to allow active power control.If this parameter is set to YES, the systemperforms power forecast in the process of initialaccess assignment or service channel activationduring intra-BSC handovers, and sends theforecast initial power information to the BTSsthrough channel activation messages. In thisway, the MSs and BTSs can adjust the transmitpower. If this parameter is set to NO, the systemdoes not perform power forecast, and the MSsand BTSs choose the maximum transmit power.GUI Value Range: NO(No), YES(Yes)Actual Value Range: NO, YESUnit: NoneDefault Value: NO


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MRMISSNUM BSC6900 SETGCELLPWR3(Optional)

Meaning: When the number of the lostmeasurement reports exceeds this parameterduring a power control period, the power controlstops.


ULREXLEVEXPFLTLEN


Meaning: When the network receivesmeasurement reports, the measurement valuesin several straight measurement reports arefiltered to reflect the radio operating environmentfor the sake of accuracy. This parameters

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