01 g-lii 301 power control algorithm of bsc6000-20081028-a-2.0

8/3/2019 01 G-LII 301 Power Control Algorithm of BSC6000-20081028-A-2.0

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Content

Overview

Huawei II Power Control Algorithm

Huawei III Power Control Algorithm


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HUAWEI TECHNOLOGIES CO., LTD. Page 3Huawei Confidential

What is power control?

What is the aim of power control?

Power control: Adjust the transmit power of BTS and MS according

to the requirement.

Aim: Reduce the transmit power of BTS and MS on the basis of

ensured call quality, thus reducing the interference of the wholenetwork and reducing power consumption

Basis: Measurement reports from MS and BTS

Overview


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Value measured

at downlink

Value measured at uplinkValue measured at uplink

ClassificationPower control includes uplink power control and downlink power

control and they are performed separately.

Uplink power control

adjust the transmit power of MS

Downlink power control

adjust the transmit power of BTS

Based on time slot

Multiplexer supersaturating

UL PC Allowed

DL PC Allowed

15 levels30dB

GSM900 20 levelsGSM900 or DCS1800 32 levels


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Power Control Algorithm

PC Execution

Processing MR

PC Decision

The principles of power control

If receive level or signal quality is higher

than the expected value, the power is

reduced to some extent.

If receive level or signal quality is lower

than the expected value, the power is

increased to some extent.

Improve the accuracy and effectiveness of

the power control on the overall basis of

receive level and signal quality.


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Huawei II Power Control Algorithm

HWIII Power Control Switch 0


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Where Where power control is performed BTS or BSC)

Aim: reduce the load over Abis interface

improve the load over the BSC

shortening the response time

In 16K mode, if a TRX is configured with two or more SDCCHs, or if SD Dynamic

Allocation Allowed is set to Yes, it is recommended that you enable BTS MR pre-

processing. Recommendation that MR is reported once per second.

MR Preprocessing

Transfer original MR

Transfer BS/MS power class

Sent Freq of preprocessed MR

Notice

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What Processing MR includes 3 step

Interpolation

Sequence number is incontinuous.

Lost of MRs Allowed MR Number Lost

RxlevRxqualBsPwrLevel linear interpolation

MsPwrLevel No interpolation

Compensation

RXLEV power class decrease/increase 2

Filter

Averaging filter

Filter length for UL RX_LEV

Filter Length for DL RX_LEV Filter Length for UL Qual

Filter Length for DL Qual

MR Compensation Allowed

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How Step1: Power control request according to the RXLEV

Adjustment based on level = [RXLEV (upper threshold + lower threshold)/2]

Minus (-) means increase output power, positive (+) means decrease output power.

Requested adjustment increaseMAX Up Adj. PC Value by RX_LEV

Requested adjustment decrease Max Down Adj. Value Qual. Zone X

Step 2: Power control request according to the RXQUAL

RxQual>= UL/DL Qual Lower Threshold increase power Requested

adjustment MAX Up Adj.C Value by Qual RxQual


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Example Assumption

The uplink RXLEV is -85 dBm

The RXQUAL class is 4.

The data configuration is as follows:

UL RX_LEV Upper Thrsh.: -60 dBm

UL RX_LEV Lower Thrsh.: -80 dBm

UL Qual. Upper Thrsh.: 0

UL Qual. Lower Thrsh.: 2 MAX Down Adj. Value Qual. Zone 0: 16 dB

MAX Down Adj. Value Qual. Zone 1: 8 dB

MAX Down Adj. Value Qual. Zone 2: 4 dB

MAX Up Adj. PC Value by RX_LEV: 16 dB

MAX Up Adj. PC Value by Qual.: 4 dB

What is the stable uplink

RXLEV after power control?

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SA0 SA1SA0 SA0SA1SA1 SA2SA2SA2 SA3SA3SA3

BTS sends commands for

adjusting power and TA through

SACCH

MS gets power control

information

MS begins to send the

measurement report in the

previous multiframe

Among 26 multiframes,

the 12th frame sends

SACCH

BTS receives the

measurement report

The period for SACCH report is:

26 4104frames480ms

MS begins to use

new power and TA

MS begins to report new information of TA and

power control through the new SACCH

Implementation To MS three MR periods are needed from the command is

sent to the command is performed.

To BTS in the first MR periods the command is performed.

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Huawei III Power Control Algorithm

HWIII Power Control Switch 1


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What Processing MR

Interpolation

Sequence number is incontinuous.

Lost of MRs 5

Rxlev(k) Rxlev(k-1) ; Rxqual(k)Rxqual 7

BsPwrLevelMsPwrLevel No interpolation

Filter

Exponential filtering

ca_filtered1 (1) = ca (1); k=1

ca_filtered1 (k) = a*ca(k) + (1-a)*ca_filtered1 (k-1) k>1

qa_filtered1 (1) = qa(1); k=1

qa_filtered1 (k) = a*qa(k) + (1-a)*qa_filtered1 (k-1) k>1

arepresent the filter coefficients, a = 1 / (2^(K/2))K is filter length

ca(k)is acuual signal strength in the kth MR

qa(k) is acuual quality in the kth MR

ca_filtered1 (k)is the filtering value for signal strength.

qa_filtered1 (k)is the filtering value for quality

HWIII UL/DL RexLev Exponent Filter Length

HWIII UL/DL Rex Qual. Exponent Filter Length

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HowStep1: Whether power control is necessary

If( (SThrUp >= ca_filtered(k) >= SThrDown)

&& (QThrUp >= qa_filtered(k) + QOffFh>= QThrDown) )

step(k) = step(k-1);

end;

else

go on;

SThrUp meansHWIII DL RexLev Upper Threshold

SThrDown meansHWIII DL RexLev Lower Threshold

QThrUp meansHWIII DL RexQual. Upper Threshold

QThrDown means

HWIII DL RexQual. Lower Threshold

QOffFh means hopping gain based on the lenth of MA, mapping as follow:

4691214161822CIR (dB)

76543210Rxqual

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HowStep 2: Calculation step

BTS PC

step(k) = - ( sfactor*( BsTxMaxPower - g(k) - SThr) + qfactor*( qa_filtered(k) + QOffFh - QThr));

MS PC

step(k) = - ( sfactor*( MsTxMaxPower - g(k) - SThr) + qfactor*( qa_filtered(k) + QOffFh - QThr));

If step(k) >0step(k) =0;

SfactormeansHWIII RexLev Adjust FactorqfactorHWIII Rex Qual.Adjust Factor

g(k) means channel gain based on current transmit power and receive level

SThrmeans the average ofRxLev Upper ThresholdandLower Threshold

QThrmeans the average ofRxQual Upper ThresholdandLower Threshold

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HowStep3: Protection and order

Protection of step:

if step(k) - step(k-1) < MaxDownSizestep(k) = step(k-1) + MaxDownSize;

else if step(k) - step(k-1) > MaxUpSize

step(k) = step(k-1) + MaxUpSize;

End

PC order

If step(k) step(k-1)

To BTSP = step(k)

To MS

P = MsTxMaxPower + step(k)

HWIII MAX Down Step

HWIII MAX Up Step

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Example Assumption

Rxlev is -83dBm, Rxqual is 4. Power Level is 0

The data configuration is as follows

HWIII DL RexLev Upper/Lower Threshold : 33/25,

HWIII DL RexQual. Upper/Lower Threshold : 18/14.

HWIII DL RexLev Adjust Factor : 0.4

HWIII DL Rex Qual.Adjust Factor : 0.6

HWIII MAX Down Step : 6

HWIII MAX Up Step 8

No hopping

What is PC order?

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AnswerStep1: whether PC is necessary

HWIII DL RexLev Upper/Lower Threshold : 33/25

Corresponding the range of Rxlev77dBm 85dBm

Current Rxlev is -83dBm in the range

HWIII DL RexQual. Upper/Lower Threshold : 18/14.

Corresponding the range of Rxqual13

Current value of Rxqual is 4 beyond the range,

PC is necessary.

Step2Calculate step

st-ep(k) = - (sfactor *( BsTxMaxPower - g(k) - SThr) + qfactor*( qa_filtered(k) + QOffFh - QThr));

g(k) = p(k) c(k);

c(k) = ca_filtered(k) + qa_filtered(k) - 10*log10 (1 + 10^( qa_filtered(k)/10));

Take it

p(k) 0 ca_filtered(k) 83 qa_filtered(k) 12

SThr81 QThr16 sfactor=0.4; qfactor=0.6;

Get step(k)=8.3

because step(k) >0 step(k) =0;

Because step(k) step(k1) =0; no PC order

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Features Exponential Filtering

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

Interpolation Optimization

Used for the lost values in the MR. Interpolation optimization uses the signal levels in the

last MR for the lost signal levels and uses a constant value 7 for the lost signal quality

values.

Comprehensive DecisionUses an universal decision formula that comprehends the receive level and quality. Thus,

the rate of the power control decision is accelerated.

Different Thresholds

The quality threshold is specified based on the service type

FH Gain

Consider the influence of frequency hopping during Power Control Judgment

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Thank you

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01 g-lii 301 power control algorithm of bsc6000-20081028-a-2.0

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