BTS Power Control R10

EUS/WZ/TI Naeem Khan Dynamic BTS Power Control Slide 1

Dynamic BTS Power Control

Radio Network Features Presentation


Purpose

• Decrease the overall downlink interference– This will increase the number of mobiles that will experience

good C/I

• Reduce BTS battery consumption– If the power supply has been cut off and the BTS is working

on battery power)

• Reduce the risk of MS receiver saturation/blocking (and thus the risk of bad speech quality)


General Comments• Power control is not performed on the BCCH carrier

• Power control is performed on TCHs and SDCCHs (SDCCHREG - switch)

• BTS power control is performed on a time slot basis

• The Resolution in output power is in step of 2dB

• The maximum power order change is 30 dB, which is also the maximum configurable dynamic power regulation

• In R10 The Algorithm in MS Power Control and BTS Power Control are the same.


Regulation Area - BTS Power vs Path loss

Path loss

Output power of the BTS

Maximum allowed power level

Minimumallowedpower level

Regulation Area

Mobile Receivedpower


Regulation Area - BTS Power vs Quality


Procedure

• Measurement preparation– Estimation of missing measurements– Decide whether full- or sub-set shall be used (DTX)

• Filtering measurements– Eliminates variations of temporary nature to ensure that the

decision base for next power order is stable

• Calculation of power order– Calculate power order to achieve desired signal strength/quality– Apply power order constraints


Frequency Planning Aspects

• It is always preferable to use a dedicated BCCH band– level of interference for all TCH carriers will reduce– BCCH carriers will experience less adjacent channel interference from

the down regulated TCH carriers• Contiguous vs Staggered BCCH band

– For BTS PC, Contiguous band is better• BTS PC Recommendations

– start with moderate setting– a good strategy is to down regulate many connections with a few dB– Tuning of algorithm is done by the combination of SSDESDL and

QDESDL


RxLevRxQual

Parameter Settings*SSDESDL: -90QDESDL: 30LCOMPDL: 5QCOMPDL: 55

* Recommended parameter settings

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Impact of RxQual & RxLev on BTS PC


RxLevRxQual

Parameter SettingsSSDESDL: -90QDESDL: 20LCOMPDL: 5QCOMPDL: 55

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Only QDESDL has changed compared to the recommended settings. Regulation is less aggressive in this example

Impact of Reducing QDESDL


RxLevRxQual


* Parameter settings are moderate and more aggressive towards down regulation in this example

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Impact of Increasing QCOMPDL


RxLevRxQual


* Parameter settings are aggressive towards Quality in this example (QDESDL increased)

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Impact of Increasing QDESDL


RxLevRxQual

Regulation Towards Lower RxLev

Parameter SettingsSSDESDL: -97QDESDL: 30LCOMPDL: 5QCOMPDL: 55

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Mobiles with low signal strength also get down regulated in case of good quality


RxLevRxQual

Impact of Increased LCOMPDL


* Parameter settings are very aggressive towards down regulation

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Filter Tuning

• QLENDL (for up regulation)– determines the response time on high RxQual/interference

• SSLENDL (for up regulation)– determines the response time for SS drop

• QLENDL/SSLENDL and UPDWNRATIO– determined the response time for down regulation– e.g. QLENDL is 2, and UPDWNRATIO is 300, this gives 2 SACCH

periods filter length for up regulation and 2*300%=6 SACCH periods filter length for down regulation


Parameters Summary

• SSDESDL is the desired signal strength at the outer rim of the regulation area, set per subcell.

• QDESDL is the desired quality level measured by the receiver in the MS, set per subcell.

• LCOMPDL determines how much of the path loss that shall be compensated for in the algorithm that regulates towards quality, set per subcell.

• QCOMPDL determines the weight of the quality compensation, set per subcell.

• SSLENDL is the length of the stationary signal strength filter

• QLENDL is the length of the quality filter, set per subcell


Parameters Summary• REGINTDL is the regulation interval, set per subcell

• SDCCHREG is a switch for the regulation of SDCCH channels, set per subcell

• BSTXPWR is the maximum allowed power level for BTSs in the current subcell

• BSPWRMIN is the minimum allowed output power for the BTS on the non-BCCH frequencies, set per subcell.

• UPDWNRATIO is a BSC exchange property and is the ratio between the up- and down regulation speed.

• STEPLIMDL is a BSC exchange property and is a switch that makes it possible to limit the down regulation to 2 dB per SACCH period


Parameter Default Recommended Value Unit Name Value Value RangeSSDESDL -70 -90 -110 to -47 dBmQDESDL 20 30 0 to 70 dtquLCOMPDL 70 6 0 to 100 %QCOMPDL 30 65 0 to 100 %REGINTDL 5 1 1 to 10 SACCH PeriodsSSLENDL 5 3 3 to 15 SACCH PeriodsQLENDL 8 3 1 to 20 SACCH PeriodsSDCCHREG OFF ON ON, OFF -BSPWRMIN -20 -20 - 20 to +50 dBmBSTXPWR - - 0 to 80 dBmSTEPLIMDL OFF OFF ON, OFF -

Parameter Ranges and Default Values

BTS Power Control R10

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