microsoft power point - 5 omf010003 power control issue1

8/14/2019 Microsoft Power Point - 5 OMF010003 Power Control ISSUE1

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Copyright 2006 Huawei Technologies Co., Ltd. All rights reserved.

Power Control


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Page2Copyright 2006 Huawei Technologies Co., Ltd. All rights reserved.

Contents1. Power Control Overview

2. HWPower Control


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Power Control Overview Power control

Adjust the transmitting power of BTS and MS when needed.

Based on measurement reports of BTS and MS

Purpose

Save the power of BTS and MS

Reduce the interference of the network

Increase the quality of the network


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Power Control Overview Power control includes uplink power control and downlink

power control, Which are performed independently

Uplink power control: Adjust TX power of MS to let BTS receive

stable signal, reduce the uplink co-channel and adjacent

channel interference, reduce power consumption of MS

Downlink power control: Adjust BTS TX power to let MS receive

stable signal, reduce the downlink co-channel and adjacent

channel interference, reduce power consumption of BTS


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Power Control Overview Process of power control commands

It takes 3 measurement report periods(480ms/period) fromcommand sending to execution.

SA0 SA1SA0 SA0SA1SA1 SA2SA2SA2 SA3SA3SA3

BTS sends the command for power

control and TA in SACCH header.

MS obtains SACCH

block

MS begins to send the

measurement report of thelast multi-frame.

In the 26 multi-frames,

frame 12 sends

SACCH.

BTS receives the

measurement report

SACCCH report period:

26X4=104 frames (480ms)

MS adopts the new

power level and TA

MS begins to set up a new SACCH header

to report the new TA and power control

message.


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Power Control Overview Power control judgment

Power control judgment is controlled by BTS measurementreport pre-processing item which can be selected in handover

control data table

MR. Pre-process (measurement report pre-processing): This

switch decide where power control be processed. If

measurement report pre-processing is yes, power control is

processed in BTS, and when setting it no, power control isprocessed in BSC


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Power Control Overview Up link and Down link power control can be enabled

independently


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Contents1. Power Control Overview

2. HW Power Control


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Original data of power control -- measurement report

Network

DownlinkDownlinkmeasurementmeasurement

reportreport

Uplink MRUplink MR

BTS

HW II Power ControlHW II Power Control


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UplinkUplink

measurementmeasurement

reportreport

DownlinkDownlink

measurementmeasurementreportreport

HW II Power ControlHW II Power Control Measurement report


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Measurement report pre-processing -- interpolation

Each measurement report has a serial number. When the

serial numbers are discontinuous, this indicates that some

measurement reports must be missed. In this case, the

network will fill up the measurement report according to

interpolation algorithm.

MR MRMR MR MR

Measurementreport serialnumber n

Measurement reportserial number n+4

Consecutive measurement report flow

3 missing measurement reports3 missing measurement reports



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Measurement report pre-processing -- filtering

Calculate average results of several consecutive measurementreports to obtain the current information, reduce the influence

of some abnormal measurement reports for the judgment of

power control.

MRMR MRMR

MR MR

Consecutive measurement report flow

FilterFilter



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HW II Power Control Power control judgment process

Measurement report pre-processing

The power control

demand according to the

receiving level

Send the power controlcommand

The power control

demand according

to receiving quality

General power controljudgement


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HW II Power Control Measurement report compensation

Purpose: Ensure the accuracy of selection of the history measurement

report before filtering.

Implementation steps:

1. Put the current receiving measurement report into the measurement report

compensation queue.

2. Record the changed information of the transmitting power according to the

MS and BTS power levels in the measurement report.

3. After finish the measurement report interpolation, system will compensate

the receiving level of the history measurement report according to the power

change information. The compensated measurement reports will be the

original data in the filter process.

4. Filter the compensated measurement reports.


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HW II Power Control Measurement report compensation

The expected receiving signal level: 30

The power control will be more effective with measurement report compensation.


The power control will be more effective with measurement report compensation.

X axis

1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950

0

10

20

30

40

50

60

70

Ya

xis

Power control diagram when there ismeasurement report compensation

Diagram when there is no power control

Power control diagram when there is nomeasurement report compensation

Power control effect diagram of measurement report compensation


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HW II Power Control Measurement report prediction

Purpose: Avoid power control later than needed, the delay is

dangerous in case of poor level or bad quality

Implementation procedure

1. Analyze the tendency of MR by the historical measurement

reports after interpolation.

2. Guide by the tendency, to predict the values of measurement

report to be received. There are 0~3 measurement reports

prediction, which are configured on OMC.

3. Filter the interpolated, compensated and predicted

measurement reports, and implement power control judgment.


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HW II Power Control Measurement report prediction

1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950

X axis

15

20

25

30

35

40

4550

Y

axis

No power control

Mean filter powercontrol

Prediction filter powercontrol

Diagram of power control effect comparison between prediction filter and mean filter


The power control with prediction filter will be more effective than that with

mean filter


The power control with prediction filter will be more effective than that withmean filter


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HW II Power Control Implementation Power control demand based on receiving level.

After measurement report pre-processing, the power control

module makes a comparison between the expected signal

level and the current receiving signal level.

Calculate the transmitting power level step size to be adjusted,

making the receiving level value closer to the expected value.

Adopt variable step size when adjusting the transmitting power

according to the receiving level, so as to achieve the expected

level as soon as possible.


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HW II Power Control Implementation Power control demand based on receiving quality

After measurement report pre-processing, the power control module

makes comparison between the expected quality level and the current

receiving quality level.

Calculate the step size of the transmitting power level to be adjusted.

Increase the transmitting power in case of poor receiving quality.

Decrease the transmitting power in case of good receiving quality.

Adopt fixed step size when adjust the transmitting power according to

the receiving quality.


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HW II Power Control Implementation General power control judgment

Power control by receiving

level

Power control by receiving

quality

Power control by signal level and

quality

AdjStep_Lev AdjStep_Qul max(AdjStep_Lev,AdjStep_Qul)

AdjStep_Lev AdjStep_Qul No action

AdjStep_Lev No action AdjStep_Lev

AdjStep_Lev AdjStep_Qul AdjStep_Lev

AdjStep_Lev AdjStep_Qul max(AdjStep_Lev,AdjStep_Qul)

AdjStep_Lev No action AdjStep_Lev

No action AdjStep_Qul AdjStep_A

No action AdjStep_Qul AdjStep_B

No action No action No action


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HW II Power Control Feature Adaptive power control:

Adaptive power control refers to changeable power control

strategy according to the communication environment, it makes

power control more effective and stable.

Automatically change the adjustable maximum step size of power

control according to different communication environment

(different receiving quality).

Adopt different power control strategies according to different

communication environments (different receiving quality and level). Max. step is different between increase and decrease.


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HW II Power Control Feature Power control within the upper/lower thresholds

As for HW II power control in case of calculating powercontrol step size according to signal level and quality, the

signal level and quality have upper/lower thresholds. Power

control will not execute if the signal level and quality is within

the threshold bands.

Avoid the signal level up-and-down caused by power control.

The upper threshold can be increased dynamically in case ofbad quality.


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Measurement report compensation -- makes power control

judgment more accurate

Measurement report prediction --to avoid power control later

than needed, the delay is dangerous in case of poor level or

bad quality

Power control expected signal level and quality threshold

falls within a band, this avoids receiving signal level

fluctuate up and down frequently

HW II Power Control Advantages


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HW II Power Control Configuration[HW II power control table] main parameters[HW II power control table] main parameters 11

Parametername

MeaningValuerange

Recommendedvalue

filter length

for ULRX_LEV

How many uplink measurement reports obtained for the averageuplink signal level to be used for uplink power control adjustment. 1~20 6

filter lengthfor DL

RX_LEV

How many downlink measurement reports obtained for the averagedownlink signal level to be used for downlink power controladjustment.

1~20 6

filter lengthfor UL Qual.

How many uplink measurement reports obtained for the averageuplink quality level to be used for uplink power control adjustment.

1~20 6

filter lengthfor DL Qual.

How many downlink measurement reports obtained for the average

downlink quality level to be used for downlink power controladjustment.

1~20 6

MRcompensation

allowed

If yes, System put the currently received measurement report intothe measurement report compensation queue, and record thetransmitting power information according to MS and BTS powervalues. And then interpolation, compensate the receiving levelvalue of the record measurement report according to the powerchange information.

Yes, no Yes

UL MRnumber

predicted

The number of uplink pred. MR in the filter using for power controljudgment.

0~3reports

2

DL MRnumber

predicted

The number of downlink pred. MR in the filter using for powercontrol judgment.

0~3reports

2


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Parameter

name

MeaningValue

range

Recommended

value

PC interval Time between two power control command implementation1~30

(SACCHperiod)

5

UL RX_LEVupper

threshold

This parameter specifies the uplink signal level upper threshold.When the signal level higher than this value, calculate a power

decrement [=receiving level - (upper threshold + lowerthreshold)/2]. This decrement value should consider together with

the maximum step size allowed for different quality zone whichthe receiving signal quality located.

0~63(-110 dBm -47 dBm)

35

UL RX_LEVlower

threshold

This parameter specifies the uplink signal level lower threshold.When the signal level lower than this value, calculate a power

increase [= (upper threshold + lower threshold)/2- receiving level].This increase also consider together with the maximum step size

allowed for different quality zone which the receiving signalquality located.

0~63(-110 dBm -47 dBm)

25

UL Qual.upperthreshold

This parameter specifies the uplink quality upper threshold. Level0~7

0

UL Qual.lower

threshold

This parameter specifies the uplink quality lower threshold forpower control

Level0~7

2


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Parametername

MeaningValuerange

Recommendedvalue

DL RX_LEVupper threshold

This parameter specifies the downlink signal level upperthreshold. When the signal level higher than this value,calculate a power decrement [=receiving level (upperthreshold + lower threshold)/2]. This decrement shouldconsider together with the maximum step size allowed fordifferent quality zone which the receiving signal qualitylocated.

0~63(-110 dBm

-47 dBm)40

DL EX_LEVlower threshold

This parameter specifies the downlink signal level lowerthreshold. When the signal level lower than this value,calculate a power increase [= (upper threshold + lowerthreshold)/2- receiving level]. This increase also considertogether with the maximum step size allowed for differentquality zone which the receiving signal quality located.

0~63(-110 dBm

-47 dBm)30

DL Qual. upperthreshold

This parameter specifies the downlink quality upperthreshold for power control

Level 0~7 0

DL Qual. lowerthreshold

This parameter specifies the downlink quality lowerthreshold for power control

Level 0~7 2


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[HW II power control table] main parameters[HW II power control table] main parameters 44

Parametername

Meaning Value rangeRecommended

value

MAX Down Adj.value Qual.

zone 0

This parameter specifies the maximum downwardpower adjustment value when the Rx quality is 0.

0~30dB 16


zone 1

This parameter specifies the maximum downwardpower adjustment value when the Rx quality is 1 or

20~30dB 8


zone 2

This parameter specifies the maximum downwardpower adjustment value when the Rx quality is

equal to or more than 3.0~30dB 4

MAX Down Adj.

PC Value byQual.

The adjustment step allowed for the downwardpower control due to receiving signal quality. 0~4dB 4

HW II Power Control Configuration


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Parametername


value

MAX Up Adj.PC Value by

RX_LEV

It is used to set the maximum adjustment step forupward power control by receive level.

0~32dB 16

MAX Up Adj.PC Value by

Qual.

It is used to set the maximum adjustment step forupward power control by receive quality.

0~32dB 8

UL Qual. BadTrigThrsh

In uplink power control, when the receiving qualityof uplink is not less than this start threshold, the

actual "upper threshold of signal strength of uplink"will be added with "upper threshold offset of levelwhen the receiving quality of uplink is poor" in the

data configuration. Thus, the expected level inuplink power control can be increased furthermore.

0~7 5

UL Qual. BadUpLEVDiff

In uplink power control, when the receiving quality isnot less than "start threshold when the receiving

quality of uplink is poor", the actual "upper thresholdof signal strength of uplink" will be added with this

offset value.

0~63dB 0


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Parametername


value

DL Qual. BadTrigThrsh

In downlink power control, when the receivingquality of downlink is not less than this start

threshold, the actual "upper threshold of signalstrength of downlink" will be added with "upper

threshold offset of level when the receiving qualityof downlink is poor" in the data configuration. Thus,the expected level in downlink power control can be

increased furthermore.

0~7 5

DL Qual. BadUpLEVDiff

In downlink power control, when the receiving

quality is not less than "start threshold when thereceiving quality of downlink is poor", the actual"upper threshold of signal strength of downlink" will

be added with this offset value.

0~63dB 0


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Exercises for HW II power control

Given conditions:

The uplink receiving level is -55dBm, the quality is level 0. Power control

algorithm is HW II.

Data configuration is as follows: Uplink signal level upper threshold: -

60dBm, uplink signal level lower threshold: - 80dBm. Uplink signal upper

quality threshold: level 1. Uplink signal lower quality threshold: level 2. Thedownward adjustable step size of quality band 0 is 16dB, of quality band 1

is 8dB, and of quality 2 is 4 dB. The upward adjustable step size of

receiving level is 16dB. The upward or downward adjustable step size for

power control by quality are both 4dB.

Question: What will be the uplink stable receiving level after power

control?

ExerciseExercise


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Exercise Exercises for HW II power control

Answer.

First, transmitting power to be reduced according to receiving level =

actual receiving level -(uplink signal level upper threshold + uplink signal

level lower threshold)/2-55- (-60 + (-80))/2(-55)-(-70)15dB. As the

receiving quality is level 0, downward adjustable step size of quality band 0

can be used -- decrease 16dB.

Second, the transmitting power to be decreased according to receiving

quality = as power control adjustment step size by quality is 4dB, thus

decrease 4dB.

Therefore, according to the general judgement on power control, 15dB

should be decreased.


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Exercise Exercises for HW II power control

Answer .

After the implementation of step 1 power control, the receiving

level becomes: -55dBm-15dB= -70dBm, Suppose the quality reach

already in level 1 here.

First: the receiving level value is between -80dBm~-60dBm,

neednt adjust.

Second: the receiving quality value is between 0 and 2, neednt

adjust.

Therefore, the uplink stable receiving level =-70dBm.


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microsoft power point - 5 omf010003 power control issue1

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