01-06 Power Control

HUAWEI BSC6000 Base Station Subsystem

V900R008

Power Control

Issue 02

Date 2008-06-30

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Contents

1 Power Control.............................................................................................................................1-11.1 Overview.........................................................................................................................................................1-21.2 Availability......................................................................................................................................................1-31.3 Technical Description.....................................................................................................................................1-4

1.3.1 Classification..........................................................................................................................................1-41.3.2 Procedure for Power Control..................................................................................................................1-61.3.3 Huawei II Power Control Algorithm......................................................................................................1-71.3.4 Huawei III Power Control Algorithm..................................................................................................1-13

1.4 Capabilities....................................................................................................................................................1-161.5 Implementation..............................................................................................................................................1-16

1.5.1 Activating Power Control.....................................................................................................................1-161.5.2 Configuring Power Control..................................................................................................................1-18

1.6 Maintenance Information..............................................................................................................................1-211.7 References.....................................................................................................................................................1-23

HUAWEI BSC6000 Base Station SubsystemPower Control Contents

Issue 02 (2008-06-30) Huawei Proprietary and ConfidentialCopyright © Huawei Technologies Co., Ltd

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Figures

Figure 1-1 Procedure for Power Control..............................................................................................................1-7Figure 1-2 Procedure for Huawei II Power Control Algorithm...........................................................................1-8Figure 1-3 Procedure for Huawei III power control algorithm..........................................................................1-14Figure 1-4 Set Cell Attributes dialog box..........................................................................................................1-17Figure 1-5 Set Other Parameter dialog box........................................................................................................1-18Figure 1-6 Set Cell Attributes dialog box..........................................................................................................1-19Figure 1-7 Set Power Control Parameter dialog box.........................................................................................1-20Figure 1-8 Setting Huawei II power control parameters....................................................................................1-21Figure 1-9 Setting Huawei Ⅲ power control parameters...................................................................................1-21

HUAWEI BSC6000 Base Station SubsystemPower Control Figures


iii

Tables

Table 1-1 NEs involved in power control............................................................................................................1-3Table 1-2 GBSS products and software versions.................................................................................................1-3Table 1-3 Static power level.................................................................................................................................1-6Table 1-4 Dynamic power level...........................................................................................................................1-6Table 1-5 Comprehensive power control decision table......................................................................................1-9Table 1-6 Counters related to power control......................................................................................................1-22

HUAWEI BSC6000 Base Station SubsystemPower Control Tables


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1 Power Control

About This Chapter

1.1 OverviewThis describes the definition and purposes of the power control. Power control is used to controlthe transmit power on radio links to improve transmission quality and reduce channelinterference.

1.2 AvailabilityThis lists the NEs and software required for the implementation of power control.

1.3 Technical DescriptionThis describes the technical aspects of the power control, such as classification, procedure, andalgorithm of the power control.

1.4 CapabilitiesNone

1.5 ImplementationThis describes how to activate and configure the power control.

1.6 Maintenance InformationThis describes the counters related to power control.

1.7 References

HUAWEI BSC6000 Base Station SubsystemPower Control 1 Power Control


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1.1 OverviewThis describes the definition and purposes of the power control. Power control is used to controlthe transmit power on radio links to improve transmission quality and reduce channelinterference.

Definition

Power control is an important method for radio link control. The BSC decides whether thetransmit power required by the MS and the BTS should be adjusted, based on the expected value,measurement reports on uplink/downlink receive level and receive quality sent by the BTS.

The principles of power control are as follows:

l If receive level or receive quality is higher than the expected value, the power is reducedto some extent.

l If receive level or receive quality is lower than the expected value, the power is increasedto some extent.

l Improve the accuracy and effectiveness of the power control on the overall basis of receivelevel and receive quality.

Purposes

Power control is used to control the transmit power required by MS or BTS while maintainingthe quality of the radio links. When the transmit power levels of the MS or BTS are minimized,interference to co-channel users is reduced.

Terms

Terms Definition

Call connection Completes the establishment and release of various callservices, including speech calls, short messages, VGCS/VBS, CS data services, and GPRS/EDGE services.Implements BSSMAP and RR procedure, including systeminformation, paging, immediate assignment, assignment,handover, location update, and A interface circuitmanagement.

Pn Maximum transmit power

Acronyms and Abbreviations

Acronyms andAbbreviations

Full Spelling

MS Mobile Station

BSC Base Station Controller

1 Power ControlHUAWEI BSC6000 Base Station Subsystem

Power Control

1-2 Huawei Proprietary and ConfidentialCopyright © Huawei Technologies Co., Ltd

Issue 02 (2008-06-30)

Acronyms andAbbreviations

Full Spelling

MR Measure report

BTS Base Transceiver Station

CIR Carrier to Interference Ratio

FS Full-rate Speech

HS Half-rate Speech

1.2 AvailabilityThis lists the NEs and software required for the implementation of power control.

NEs Involved

Table 1-1 lists the NEs involved power control.

Table 1-1 NEs involved in power control

MS BTS BSC MSC MGW SGSN GGSN HLR

√ √ √ – – – – –

NOTE

l -: not involved

l √: involved

Software Releases

Table 1-2 lists the versions of GBSS products that support power control.

Table 1-2 GBSS products and software versions

Product Version

BSC BSC6000 V900R008C01 and later releases

BTS BTS3012 DTRU BTS3000V100R001C01 and later releases

QTRU BTS3000V100R008C01 and later releases

BTS3012AE DTRU BTS3000V100R001C04 and later releases

QTRU BTS3000V100R008C01 and later releases

BTS3006C BTS3000V100R002C01 and later releases



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Product Version

BTS3002E BTS3000V100R002C01 and later releases

DBS3900 GSM BTS3000V100R008C01 and later releases

BTS3900 GSM BTS3000V100R008C02 and later releases

BTS3900A GSM BTS3000V100R008C02 and later releases

MiscellaneousNone

1.3 Technical DescriptionThis describes the technical aspects of the power control, such as classification, procedure, andalgorithm of the power control.

1.3.1 ClassificationThis describes the classification of power control. The power control is classified into uplinkpower control and downlink power control, namely, MS power control and BTS power control.

1.3.2 Procedure for Power ControlThis topic describes the procedure of power control. The procedure consists of threemeasurement report periods. In the first period, the BTS sends the MS a power control commandmessage. In the second period, the MS performs the power adjustment. In the third period, theMS notifies the BTS of the adjusted power.

1.3.3 Huawei II Power Control AlgorithmThis describes the procedure and features of Huawei II power control algorithm.

1.3.4 Huawei III Power Control AlgorithmThis describes the procedure and features of Huawei Ⅲ power control algorithm.

1.3.1 ClassificationThis describes the classification of power control. The power control is classified into uplinkpower control and downlink power control, namely, MS power control and BTS power control.

1.3.1.1 Power Control for MSThis describes the power control for the MS. If the transmit power of the MS is controlledproperly, the BTS can maintain stable receive levels and the co-channel interference isminimized.

1.3.1.2 Power Control for BTSThis describes the power control for the BTS. If the transmit power of the BTS is controlledproperly, the MS can maintain stable receive levels, the co-channel interference is minimized,and the power consumption of the BTS is reduced.


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Power Control for MS

This describes the power control for the MS. If the transmit power of the MS is controlledproperly, the BTS can maintain stable receive levels and the co-channel interference isminimized.

The MS power control is performed at two phases: initial adjustment phase and stable adjustmentphase. The differences of power control between the initial adjustment phase and the stableadjustment phase lie in the expected uplink receive level and receive quality, and filter length.Moreover, only downward power adjustment is performed at the initial adjustment phase.

1. Initial adjustment phase

Initial adjustment takes place when a call connection is established. When a call connectionoccurs, the MS accesses to the network at the power set by MS_TXPWR_MAX_CCH.If the MS does not support a power level, it transmits at the proximate supported powerlevel.

As the BTS supports multiple calls simultaneously, it must minimize the receive level ofa new call to ensure the quality of other calls. In addition, the strong interference from onecell has impacts on the QoS of the calls in other cells.

For the classmark 3 MS that supports DCS1800, the MS accesses to the network with thepower set by MS_TXPWR_MAX_CCH and Power Deviation when a call connectionoccurs. If the filtered level is lower than the expected level, power control is not performed.If the filtered level is not lower than the expected level, power control is performedaccording to the following regulations:

l Power to be decreased = (initial power – expected initial power) x compensation factorof UL path loss

l Power after adjustment = current power – power to be decreased

The purpose of power adjustment in the initial phase is to decrease the transmit power ofthe MS as soon as possible until measurement reports on stable transmit power are obtained.Then, the MS can adjust its transmit power based on the power control algorithms for stablepower adjustment.

2. Stable adjustment phase

After the MS accesses to the network and the call lasts for a certain duration, and after theBTS receives a certain number of UL measurement reports, the BTS performs interpolationand filtering to obtain the actual UL receive level and receive quality, which are comparedwith the standard UL receive level and receive quality. According to the power controlalgorithms, the BTS calculates the power level that the MS should adjust. If the calculatedpower level is different from the transmit power of the MS and meets application restrictions(such as the step restrictions of power adjustment, the restrictions of the transmit powerrange for the MS), the BTS sends a power control command to the MS.

The UL power adjustment enables the actual UL receive level and receive quality to beclose to the standard UL receive level and receive quality. The purpose of interpolation andfiltering is to handle the lost measurement reports and to ensure the stability of powercontrol algorithms.

Power Control for BTS

This describes the power control for the BTS. If the transmit power of the BTS is controlledproperly, the MS can maintain stable receive levels, the co-channel interference is minimized,and the power consumption of the BTS is reduced.



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The power control for BTS is optional. The principle of the power control for BTS is similar tothat of the power control for MS. The power control for BTS, however, is performed at only onephase: stable adjustment phase. When the received measurement reports are insufficient forfiltering, power control is not performed. Only when sufficient measurement reports arereceived, the power control for BTS is performed.

The power control for the BTS consists of static power control and dynamic power control.

l Static power controlThe static power has 11 levels numbered from 0 to 10. The difference between two adjacentstatic power levels is 2 dBm. For example, the maximum transmit power of the BTS is 46dBm, and the power values corresponding to the static power levels are listed as Table1-3.

Table 1-3 Static power level

Static PowerLevel 0 1 2 3 4 5 6 7 8 9 10

Power(dBm)

46 44 42 40 38 36 34 32 30 28 26

NOTE

You can set the static power level by setting the Power Level.

l Dynamic power controlDynamic power control refers to the fine tuning on power based on static power control.Based on a certain static power (Pn) as the maximum value, the dynamic power has 15levels with the step 2 dBm by tuning the static power value downwards. Table 1-4 lists thedynamic power values in case that Pn is equal to 42.

Table 1-4 Dynamic power level

DynamicPowerLevel 0 1 2 3 4 5 6 7 8 9

10

11

12

13

14

15

Power(dBm)

42

40

38

36

34

32

30

28

26

24

22

20

18

16

14

12

NOTE

When the maximum dynamic power cannot meet the requirements, the static power level should beaccordingly adjusted to increase the maximum dynamic power Pn.

1.3.2 Procedure for Power ControlThis topic describes the procedure of power control. The procedure consists of threemeasurement report periods. In the first period, the BTS sends the MS a power control command


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message. In the second period, the MS performs the power adjustment. In the third period, theMS notifies the BTS of the adjusted power.

Figure 1-1 shows the procedure for the power control.

Figure 1-1 Procedure for Power Control

SA 0 SA 3SA2SA 1SA 0SA 3SA 2SA 1SA 0SA 3SA 2SA 1

BTS sends powercontrol and TA commandin the header of SACCH

MS startsto use new

power and TA

MS starts tosend the MRin previousmultiframe

MS receives SACCHmessage block

MS starts to construct theheader of new SACCH to

report the new TA and powercontrol information

BTS receivesthe MR

SACCH MR period:4x26=104 frames (480 ms)

SACCH is sent in the12th frame of the 26

multiframe

1. The first measurement report periodThe BTS sends a power adjustment and TA command in the SACCH header. On receivingthe command, the MS starts to perform power control in the second measurement reportperiod.

2. The second measurement report periodThe MS starts to perform power control as follows:l If the adjustment step is set to 16 dB, 104 frames (480 ms, a measurement report period)

are required for the power adjustment.l If the step is set to 32 dB, two measurement report periods are required for the power

adjustment.NOTE

The MS changes to the new level at a maximum rate of one nominal 2 dB power control step every13 frames (60 ms).

3. The third measurement report periodThe current transmit power (actually used by the MS for the last burst of the previousSACCH period) is saved and is reported to the BTS in the next SACCH uplink measurementreport.

1.3.3 Huawei II Power Control AlgorithmThis describes the procedure and features of Huawei II power control algorithm.

1.3.3.1 Procedure for Huawei II Power Control AlgorithmThis describes the procedure for Huawei II power control algorithm, including MRcompensation, prediction filtering, adjusting the power step based on the receive level/quality,and power control performance.



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1.3.3.2 Features of Huawei II Power Control AlgorithmThis describes the features of Huawei II power control algorithm. The features include MRcompensation, prediction filtering, dual-threshold power control algorithm, variable step powercontrol, adaptive power control, bad quality signal strength upper threshold adjustment, anddetachment of uplink and downlink power control.

Procedure for Huawei II Power Control Algorithm

This describes the procedure for Huawei II power control algorithm, including MRcompensation, prediction filtering, adjusting the power step based on the receive level/quality,and power control performance.

Figure 1-2 shows the procedure for Huawei II power control algorithm.

Figure 1-2 Procedure for Huawei II Power Control Algorithm

Calculate power adjustment step based on both receive

level and receive quality

Start

Calculate power adjustment step based on receive

quality

End

Perform power control

Compensate MRs (Compensate level)

MR prediction filtering

Calculate power adjustment step based on receive level

1. Power control based on the receive level


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If UL/DL RX_LEV Upper Threshold < UL/DL receive level < UL/DL RX_LEV LowerThreshold, power control is not required. If the condition is not met, power control isrequired.l If the receive level is less than UL/DL RX_LEV Lower Threshold, the power needs

to be increased.Power increment = (upper threshold + lower threshold)/2 – receive level. If the valueexceeds the value of MAX Up Adj. PC Value by RX_LEV, take the value of MAXUp Adj. PC Value by RX_LEV instead.

l If the receive level is greater than UL/DL RX_LEV Upper Threshold, the power needsto be decreased.Power decrement = receive level – (upper threshold + lower threshold)/2. This valuemust be within the maximum power control range of the corresponding quality zone.If the value exceeds the range, take the maximum value instead.

2. Power control based on the receive qualityIf UL/DL Qual Upper Threshold < UL/DL receive quality < UL/DL Qual LowerThreshold, power control is not required. If the condition is not met, power control isrequired.l If the receive quality is equal to or greater than UL/DL Qual Lower Threshold, the

power needs to be increased.Power increment = MAX Up Adj. PC Value by Qual

l If the receive quality is less than UL/DL Qual.Upper Threshold, the power needs tobe decreased.Power decrement = MAX Down Adj. PC Value by QualNOTE

The level adjusted on the basis of the receive quality is a definite value, while the level adjusted onthe basis of the receive level is calculated using a formula.

3. Comprehensive power control decisionTable 1-5 describes the comprehensive power control decision.

Table 1-5 Comprehensive power control decision table

Level andQuality

Power ControlBased onReceive Level

Power ControlBased on ReceiveQuality

ComprehensivePower Control

Good level andgood quality

↓AdjStep_Lev ↓AdjStep_Qul ↓MAX(AdjStep_Lev,AdjStep_Qul)

Good level andpoor quality

↓AdjStep_Lev ↑AdjStep_Qul No action

Good level andnormal quality

↓AdjStep_Lev No action ↓AdjStep_Lev

Poor level andgood quality

↑AdjStep_Lev ↓AdjStep_Qul ↑AdjStep_Lev

Poor level andpoor quality

↑AdjStep_Lev ↑AdjStep_Qul ↑MAX(AdjStep_Lev,AdjStep_Qul)



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Level andQuality

Power ControlBased onReceive Level

Power ControlBased on ReceiveQuality

ComprehensivePower Control

Poor level andnormal quality

↑AdjStep_Lev No action ↑AdjStep_Lev

Normal level andgood quality

No action ↓AdjStep_Qul ↓AdjStep_A

Normal level andpoor quality

No action ↑AdjStep_Qul ↑AdjStep_B

Normal level andnormal quality

No action No action No action

The parameters in the table are described as follows:

l AdjStep_Lev

Adjusting the receive level

l AdjStep_Qul

Adjusting the receive quality

l No action

No adjustment

l AdjStep_A

– When Uplink (Downlink) receive level – AdjStep_Qul < UL/DL RX_LEV LowerThreshold, AdjStep_A = 0. Power control is not required.

– When Uplink (Downlink) receive level – AdjStep_Qul ≥ UL/DL RX_LEV UpperThreshold, AdjStep_A = AdjStep_Qul.

The purpose is to avoid unnecessary power control in case of normal level and goodquality. If the power is adjusted in case of normal level and good quality, the levelbecomes poor and another power control procedure is required. Thus, power control isperformed frequently.

l AdjStep_B

– When AdjStep_Qul + Uplink (Downlink) receive level > UL/DL RX_LEV UpperThreshold, AdjStep_B = UL/DL RX_LEV Upper Threshold – UL/DL receive level.Thus, the adjusted level does not exceed the level upper threshold.

– When AdjStep_Qul + UL/DL receive level ≤ UL/DL RX_LEV LowerThreshold, AdjStep_B = AdjStep_Qul.

The purpose is to avoid unnecessary power control in case of normal level and poorquality. If the power is adjusted in case of normal level and poor quality, the levelbecomes good and another power control procedure is performed. Thus, power controlis performed frequently.

NOTE

In Table 1-5, ↑ indicates increasing power, and ↓ indicates decreasing power.


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Features of Huawei II Power Control Algorithm

This describes the features of Huawei II power control algorithm. The features include MRcompensation, prediction filtering, dual-threshold power control algorithm, variable step powercontrol, adaptive power control, bad quality signal strength upper threshold adjustment, anddetachment of uplink and downlink power control.

MR Compensation

During power control decision, the BSC performs weighted filtering on the values of the receivedlevel and of the received quality in several history measurement reports. The measurementreports may be obtained by the BTS/MS at different transmit power. To ensure the accuracy ofthe values for filtering, the values in the history measurement reports that are obtained at adifferent transmit power from the current power must be compensated. If the currentlyinterpolated MRs and the compensated MRs are filtered together, the power control decisioncan be more effective. You can set the MR.Compensation Allowed to determine whethermeasurement report compensation is performed.

The measurement report compensation is calculated as follows:

l If the reported power level of the MS (BTS) is greater than last time (that is, power leveldecreases), the uplink (downlink) receive level in all the MR is subtracted from the variationvalue of the power of the MS (BTS) (variation of power level x 2 dBm).

l If the reported power level of the MS (BTS) is lower than last time (that is, power levelincreases), the uplink (downlink) receive levels in all the MRs are added by the variationvalue of the power of the MS (BTS) (added power level x 2 dBm).

NOTE

The measurement report compensation is for level instead of quality.

Prediction Filtering

The power control decision is performed based on the average filter value in history measurementreports. That is, the average filter value is used as a reference for the current receive level. Thereis an interval between power control decision and power adjustment, which delays the poweradjustment. Therefore, prediction filtering is added.

The principle of prediction filtering is that the variation of receive level and receive qualitymaintains continuity in a short period of time. Prediction filtering samples N MRs, appliesweighting filter to them, and gives prediction on 0–3 MRs from the current time onwards.Generally, the interval between power control decision and power adjustment is three MRs(about 1.5s). Prediction filtering can ensure the accuracy of prediction. Power control decisionis implemented by filtering the predicted MR along with the interpolated MR or compensatedMR.

Prediction filtering enables the MR that power control decision is based on to accurately reflectthe radio environment when power adjustment occurs. Thus, the hysteresis for power adjustmentcan be minimized.

NOTE

Power control algorithm is applied only to the receive level. If the filter length is less than 5 or the numberof predicted MRs is 0, the mean value filtering is applied.



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Dual-Threshold Power Control Algorithm

Power control is used for the purpose of achieving good speech quality with low receive level.Because of the radio link instability and external interference, the transmit power cannot be toolow. Therefore, Huawei adopts the strategy of dual-threshold power control algorithm. Dual-threshold power control algorithm adopts the following strategies:

l Adjusting the power step based on the receive level

The threshold of the receive level is set to a dual threshold. Variable step for power controlis used for fast and accurate power control. The current receive quality is also consideredfor determining power adjustment step.

l Adjusting the power step based on the receive quality

The changing of receive quality is related to interference. The major interference in GSMis the co-channel interference during frequency reuse. When the power of a call is increased,co-channel interference is exerted on another call. The following case should be avoided:If the power of the first call is increased, the interference in a second call is enhanced sothat the receive quality of the second call gets poor. To get a better quality, the transmitpower of the second call may be increased. By analogy, the group effect may occur.

The threshold of the receive quality is also set to a dual threshold. If the receive quality iswithin the threshold band, adjusting the transmit power is not required. If the receive qualityis beyond the threshold band, adjusting the transmit power is required. For the poweradjustment caused by quality-related reasons, use a fixed step to avoid oscillation.

l Adjusting the power control based on the receive level and receive quality

The effect on power control of both level and quality is considered. On one hand, therequirements of both level and quality are met to the maximum extent. On the other hand,in case difference or opposite requirements for level and quality, the stability of thealgorithm should be fully considered to prevent an unstable adjustment procedure.

Variable Step Power Control

Variable step power control is achieved according to the following regulations:

l When the difference between the current level and quality and the expected level and qualityis big, adjust power with long step.

l When the difference between the current level and quality and the expected level and qualityis small, adjust power with short step.

Adaptive Power Control

Adaptive power control changes the power control strategy based on the communicationenvironment, making the power control effective and stable. The adaptive power control consistsof the following two elements:

l Automatically changing the maximum variable step of the power control based on thecommunication environment.

l Adopting corresponding power control strategy based on the communication environment.

Bad Quality Signal Strength Upper Threshold Adjustment

When you use the dual-threshold power control algorithm, do as follows:


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l When the receive quality is higher than the UL/DL QUAL.Bad Trig Threshold, increasethe UL/DL RX_LEV Upper Threshold value and add UL/DL Qual.Bad UpLEVDiff.

l When the receive quality is good, set the UL/DL RX_LEV Upper Threshold to a smallvalue to reduce the transmit power of the BTS and MS.

l When the receive quality is bad, set the UL/DL RX_LEV Upper Threshold to a greatvalue to improve the speech quality.

Detachment of Uplink and Downlink Power ControlThe detached configuration of power control step in upward and downward directions enablesflexible and fast power control based on the actual situation on the network. When the uplink(downlink) signal quality or the receive quality becomes poor immediately, the upward powercontrol can be performed quickly. Thus call drop can be avoided.

1.3.4 Huawei III Power Control AlgorithmThis describes the procedure and features of Huawei Ⅲ power control algorithm.

1.3.4.1 Procedure for Huawei III Power Control AlgorithmThis describes the procedure for Huawei III power control algorithm, including processing lostmeasurement reports, filtering, calculating FH gain, calculating power adjustment step based onthe FH gain, and performing power control.

1.3.4.2 Features of Huawei III Power Control AlgorithmThis describes the features of Huawei III power control algorithm. Based on Huawei Ⅱ powercontrol algorithm, Huawei III power control algorithm has the following enhancements:exponential filtering, interpolation optimization, comprehensive decision, different thresholds,and FH gain.

Procedure for Huawei III Power Control AlgorithmThis describes the procedure for Huawei III power control algorithm, including processing lostmeasurement reports, filtering, calculating FH gain, calculating power adjustment step based onthe FH gain, and performing power control.

Figure 1-3 shows the procedure for Huawei Ⅲ power control algorithm.



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Figure 1-3 Procedure for Huawei III power control algorithm

Process lost MRs (Interpolation optimization)

Start

Calculate FH gain

Calculate power adjustment step based on FH gain

Perform power control

End

Process MR filtering (Exponential filtering and

slide window filtering)

1. Power control decisionIn Huawei ⅢⅢⅢ power control algorithm, the power control decision is based on signallevel and signal quality. The conditions for power control decision are as follows:l Whether the UL/DL receive level ranges from HWIII UL/DL RexLev Upper

Threshold and HWIII UL/DL RexLev Lower Threshold.l Whether the sum of UL/DL receive quality and HWIII MA FreqHop Gain ranges

from HWIII UL/DL FS/HS/AFS/AHS Rex Qual.Upper Threshold and HWIII UL/DL FS/HS/AFS/AHS Rex Qual. Lower Threshold.

If both the receive level and the receive quality range from the upper thresholds and thelower thresholds, the power control is not required and the power control step remainsunchanged.


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NOTE

l The power control decision on the BTS and the power control decision on the MS areimplemented simultaneously.

l You can obtain the HWIII MA FreqHop Gain from the frequency hopping gain table based onthe number of MA frequencies. If there are more than eight MA frequencies, obtain the receivequality gain when the number of MA frequencies equals eight.

l The step of Huawei Ⅲ power control algorithm indicates the offset value between the transmitpower of the BTS or MS and the maximum transmit power, instead of the actual value of theoffset to be adjusted. This is where the difference between the Huawei Ⅱ power control algorithmand the Huawei Ⅲ power control algorithm lies.

2. BTS/MS power control performanceThe power control adjustment step is generated based on receive quality and receive levelin each HWIII Up Link/Down Link Power Control Adjust Period.The step range needs to be restricted as follows to prevent excessive adjustment:l The adjustment step must not exceed the HWIII UL MAX UpStep/DownStep.

l If the generated step does not equal the last step, the BSC sends to the BTS/MS a powercontrol command to adjust the power level of the BTS/MS.

Features of Huawei III Power Control AlgorithmThis describes the features of Huawei III power control algorithm. Based on Huawei Ⅱ powercontrol algorithm, Huawei III power control algorithm has the following enhancements:exponential filtering, interpolation optimization, comprehensive decision, different thresholds,and FH gain.

Exponential FilteringExponential filtering accelerates the processing rate for the filtering based on the MRs.

To calculate the filtered signal level (quality), the exponential filtering applies the weightedaverage method to the signal level (quality) in the MR of this time with the signal level (quality)in the last MR. The weighted coefficient is calculated based on HWIII UL/DL Rex Qual.Exponent Filter Length and HWIII UL/DL RexLev Exponent Filter Length.

Interpolation OptimizationInterpolation optimization is used for the lost values in the MR. Interpolation optimization usesthe signal levels in the last MR for the lost signal levels and uses a constant value 7 for the lostsignal quality values.

NOTE

If the number of continuously lost MRs is greater than HWIII Number of lost MRs allowed, the BSCstops the power control procedure until it receives an MR.

Comprehensive DecisionDifferent power control algorithms use different methods for the comprehensive decision basedon the receive level and quality. Huawei Ⅱ power control algorithm uses the dual-threshold(level and quality) method and divides the coverage area into smaller areas for separatecomprehensive decisions. Huawei Ⅲ power control algorithm uses an universal decision formulathat comprehends the receive level and quality. Thus, the rate of the power control decision isaccelerated.



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Different ThresholdsHuawei Ⅲ power control algorithm uses different quality thresholds for different rates. Differentrate coding schemes have different requirements for CIR. When half-rate channels are seized,half-rate quality threshold is used; when full-rate SDCCHs are seized, full-rate quality thresholdis used.

At present, only the speech services are considered. The quality threshold for CS data servicesuses either the full-rate or half-rate threshold based on the type of the occupied channel.

FH GainWith the FH gain, the BTS can detects the frame error rate (FER) of the speech coding. Therefore,the speech quality is significantly improved.

1.4 CapabilitiesNone

1.5 ImplementationThis describes how to activate and configure the power control.

1.5.1 Activating Power ControlThis describes how to activate the power control on the BSC6000 Local MaintenanceTerminal.

1.5.2 Configuring Power ControlThis describes how to configure the power control on the BSC6000 Local MaintenanceTerminal.

1.5.1 Activating Power ControlThis describes how to activate the power control on the BSC6000 Local MaintenanceTerminal.

Procedure

Step 1 On the BSC6000 Local Maintenance Terminal, right-click a cell on the Management Treetab page. Then, choose Configure Cell Attributes.

Step 2 In the displayed dialog box, double-click the target cell in the Cell view list box to add it to theSelected cells list box. Then, click Next.

Step 3 In the Cells to be set list box, select the target cell, and then click Set Cell Properties. A dialogbox is displayed, as shown in Figure 1-4.


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Figure 1-4 Set Cell Attributes dialog box

Step 4 Click Other Attributes. A dialog box is displayed. Click Advanced, and then select the PublicChannel Control tab, as shown in Figure 1-5.

Set the PWRC to Yes.



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Figure 1-5 Set Other Parameter dialog box

Step 5 Click OK to return to the upper-level menu until the configuration is complete.

----End

1.5.2 Configuring Power ControlThis describes how to configure the power control on the BSC6000 Local MaintenanceTerminal.

Procedure

Step 1 On the BSC6000 Local Maintenance Terminal, right-click a cell on the Management Treetab page. Then, choose Configure Cell Attributes.

Step 2 In the displayed dialog box, double-click the target cell in the Cell view list box to add it to theSelected cells list box. Then, click Next.

Step 3 In the Cells to be set list box, select the target cell, and then click Set Cell Properties. A dialogbox is displayed, as shown in Figure 1-6.


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Figure 1-6 Set Cell Attributes dialog box

Step 4 Click Power Control. A dialog box is displayed, as shown in Figure 1-7.

Set the Power Control Algorithm Switch to HuaweiⅡ Power Contrl or HuaweiⅢ PowerContrl.



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Figure 1-7 Set Power Control Parameter dialog box

Step 5 Click Advanced. The dialog box for setting the advanced power control parameters is displayed.To set the parameters, do as follows:l If the Power Control Algorithm Switch is set to HuaweiⅡ Power Contrl, set the parameters

by referring to HW II Power Control, as shown in Figure 1-8.


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Figure 1-8 Setting Huawei II power control parameters

l If the Power Control Algorithm Switch is set to HuaweiⅢ Power Contrl, set the parametersby referring to HW III Power Control, as shown in Figure 1-9.

Figure 1-9 Setting Huawei Ⅲ power control parameters

Step 6 Click OK to return to the upper-level menu until the configuration is complete.

----End

1.6 Maintenance InformationThis describes the counters related to power control.



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AlarmsNone

CountersTable 1-6 lists the counters related to the power control.

Table 1-6 Counters related to power control

Counter Description

S3230A Number of Power Control IncreaseMessages Sent to MS

S3230B Number of Power Control DecreaseMessages Sent to MS

S3231A Number of Power Control IncreaseMessages Sent to BTS

S3231B Number of Power Control DecreaseMessages Sent to BTS

S3240 MS Power Rank

S3241 BTS Power Rank

AS3240 Mean Power Rank of MS

AS3241 Mean Power Rank of BTS

H330D Downlink Signal Strength

H330C Uplink Signal Strength

AS325B Mean Strength of Downlink Signals

AS325A Mean Strength of Uplink Signals

H330B Downlink Signal Quality

H330A Uplink Signal Quality

AS326B Mean Quality of Downlink Signals

AS326A Mean Quality of Uplink Signals

S327B Number of Times (Maximum DownlinkTransmit Power)

S327A Number of Times (Maximum UplinkTransmit Power)

RS327B Ratio of Maximum Downlink PowerDuration (%)

RS327A Ratio of Maximum Uplink PowerDuration (%)


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Counter Description

TS327B Duration of Maximum Downlink Power

TS327A Duration of Maximum Uplink Power

S3280 Distance Between MS and BTS

S3281 Maximum Distance Between MS andBTS

S329 Number of Power Control Messages

AS3280 Mean Distance Between MS and BTS

1.7 References

l GSM 04.08“Digital cellular telecommunications system (Phase 2+); Mobile radio interface layer 3specification”

l GSM 05.08 (prETS 300 578)“Radio subsystem link control”



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01-06 Power Control

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