OMF010003 Power Control ISSUE1.4

8/11/2019 OMF010003 Power Control ISSUE1.4

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OMF010003 Power Control

ISSUE1.4

OMF010003 Power ControlOMF010003 Power Control

ISSUE1.4ISSUE1.4

Wireless Training Department


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Power control overview

HW power control

HW power control

Course ContentsCourse Contents


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Power Control OverviewPower 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 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.

1. During handover, MS will access the target cell with the maximum transmitting

power (associated handover command) allowed by the target cell. But if MS power

prediction after HO is enable, then MS will use the optimized power to access the

target cell.

2. During intra-cell handover, the current power will be retained.

3. Power control can be implemented on TCH carriers only, BCCH carrier is not

allowed power control. Because MS needs to measure the receiving level of BCCH

from the adjacent cell. It will be inaccurate when power control is performed on

BCCH.

4. Power control is performed independently for each channel.


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! Process of power control commands

" It takes 3 measurement report periods(480ms/period) from

command sending to execution.

SA0SA0SA0SA0 SA1SA1SA1SA1SA0SA0SA0SA0 SA0SA0SA0SA0SA1SA1SA1SA1SA1SA1SA1SA1 SA2SA2SA2SA2SA2SA2SA2SA2SA2SA2SA2SA2 SA3SA3SA3SA3SA3SA3SA3SA3SA3SA3SA3SA3

BTS sends the command for power

control and TA in SACCH header.

MS obtains SACCH

block

MS begins to send the

measurement report of the

last 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 newpower level and TA

MS begins to set up a new SACCH header

to report the new TA and power control

message.

When MS accesses the network via RACH channel, its transmitting power is the

MS max. TX power level get from the system information sent on BCCH. MS

send the first message on dedicated channel also uses the MS max TX power

level ,this is not under the control of the system before the power control command

which carried on SACCH of SDCCH or TCH. The implementation procedure is as

follows:

1. According to the uplink receiving level and receiving quality reported by BTS,

consider the maximum transmitting power of MS, BSC calculates the proper

transmitting power for the MS.

2. Power control command and the TA value will be transmitted to MS at layer 1

header carried by each downlink SACCH block.

3. MS receives the power control command carried by SACCH header at the end of

each SACCH report period, Then MS will carry out the command in the beginning

of next report period. MS can change power 2dB per 13 frames (60ms) maximum.

4. After MS executed the power control command, it will set the current power class

at the layer 1 message header of the next uplink SACCH, and transmit it to BTS in

the measurement report. Therefore, it will take 3 measurement report periods for

the new power class (in each power control command) to be available.

Note: Each integral SACCH message block (measurement report) is composed of

4 burst. A power control implementation process in whole takes the time of 3

measurement reports.


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! Huawei power control algorithm: HW I and HW II power control

Measurement reportpre-processing

Power control algorithm

selection

Yes

HW I power control

algorithm

HW II power control

algorithm

GSM0508 power control

algorithm

HWII power control is developed based on HWI. Its more sensitive and the data

configuration is simpler. For details, see later sections.

Huawei can support GSM0508 power control algorithm.


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! Power control judgment and the selection of HWI algorithm or

HWII algorithm

" Power control algorithm selected in power control data table

" Power control judgment is controlled by BTS measurement

report 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. Ifmeasurement report pre-processing is yes, power control is

processed in BTS, and when setting it no, power control is

processed in BSC.

Set pre-processing yes is to reduce the signaling load in Abis interface.

i.e.:

1.If Abis E1 is in 15:1 mode, it should be set yes, otherwise the Abis capacity for

speed is not enough;

2.BTS22C 0110 version should be set No;

3.Satellite transmission BTS should be set yes;

4.We should consider few type of BTS has relationship with HWI algorithm and

HWII algorithm, please check the product manual.


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HW power control

HW power control



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HW I Power ControlHW I Power Control

! HW I power control

" Process of HW I power control

" MR pre-processing

" Data configuration for HW I power control

" comparison of uplink power control with downlink power control


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! Process of HW I power control

Measurement reportpre-processing

Aim achieved ?

Power control calculation and

adjustment

N

Y


In HWI power control, after the BSC or BTS performs pre-processing (interpolation

and filtering) on the original measurement report, it will start HWI power control

algorithm, and send the power control command.

HWI power control can be separate into initial mode and stationary mode, system

will consider signal strength only in initial mode,and consider both signal strength

and quality in stationary mode.


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! Original data of power control -- measurement report

Network

DownlinkDownlinkmeasurementmeasurement

reportreport

Uplink MRUplink MR

BTSBTSBTSBTS


The original data of power control is from measurement report. MS submits a

measurement report to the network on SACCH channel every 480ms, the content

reported by MS is the downlink measurement values which received by MS.

Uplink measurement report are about the uplink signal received by BTS.


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UplinkUplink

measurementmeasurement

reportreport

DownlinkDownlink

measurementmeasurement

reportreport


! Measurement report

There are two kind of measurement report for system: FULL (full measurement)

and SUB (sub measurement).

FULL--Averaging over 100 TCH bursts(except four idle frames of four 26-multiframes).

SUB--Averaging over 12 bursts(four SACCH bursts, eight TCH bursts).


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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 MRMRMR MR

Measurement report

serial number n

Measurement report

serial number n+4

Consecutive measurement report flow

3 missing measurement reports3 missing measurement reports


The network receives the measurement reports n and n+4, which are with

discontinuous serial numbers. Therefore the three missed measurement reports

n+1, n+2 and n+3 will be filled up with some algorithm.

Note: Due to the power control judgment needs to be based on consecutive

measurement reports, the missed measurement reports should be filled up.


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! Measurement report pre-processing -- filtering

" Calculate average results of several consecutive measurement

reports to obtain the current information, reduce the influence of

some abnormal measurement reports for the judgment of power

control.

MRMR MR

MR MR MR

Consecutive measurement report flow

FilterFilter


Filter the last 4 measurement reports. There are filters respectively for

uplink/downlink receiving level and receiving quality and TA.


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[BTS power control table][BTS power control table]

! HW I power control data configuration and parameter

introduction

Parametername

Meaning Valuerange

Recommended value

DL RX_LEVExpected

The expected signal level of MS in stable status, Expected

stable downlink signal level > downlink edge HO threshold!

Otherwise, ping-pang HO will be caused.

0"63 35

DL RX_LEVCompensation

The power adjustment value varies with this parameter. Theadjustment value caused by power level equal to the differencebetween the expected signal level and the actual receivingsignal level multiply this factor.

0"100# 80#(signal ex-signalrx)*80%=adjust

ment value

DL Qual.Expected

Expected signal quality of MS in stable status. 0 " 7

Levels

1

DLQual.Compensation

The power adjustment value varies with this parameter. Theadjustment value caused by signal quality equal to10*difference between the expected signal quality level and theactual receiving signal quality level multiply this factor.

0"100# 20#[10*(qualityRX-qualityEX)*20%]

MAX PCStep

maximum adjustment range in one BTS power controlcommand

Levels0~16,2dB eachstep

8


The parameter configuration for HW I includes two sheets: [BTS power control

table] and [MS power control table] for downlink and uplink power control. When

the HW_1 in PC algorithm is selected, the network will perform power control

according to these two sheets.

Only some of key parameters are listed above.


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[BTS power control table][BTS power control table]

Parametername

Meaning Valuerange

Recommended value

BTS PCPeriod

Time interval for implementing two power control commands(unit count of SACCH period)

1"10 5

Filter lengthfor DL

RX_LEV

Content: indicating the number of measurement reports inwhich the average of uplink signal strength is taken before MSpower adjustment at stable stage. The purpose is to removethe influence of some abnormal reports. When the filter lengthis too long, the influence due to abnormal reports will beweakened, but the MS power adjustment is not timely.

1"32 5

BTS Minpower

Indicating the minimum transmitting power value supported bythe BTS

0~36 4

BTS Maxpower

Indicating the maximum transmitting power value supportedby the BTS.

0~56 According toBTS type

Only some of key parameters are listed above.


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[MS power control data table][MS power control data table]Parameter

name

Meaning Value range Recom-

mendedvalue

initialRX_LEVexpected

The expected BTS receiving signal level in the initial stagewhen MS access the network.

0~63dBm 30

StableEX_LEVExpected

The expected BTS receiving signal level in stable status.Expected stable signal level > uplink margin HO threshold(HO parameter). Otherwise, ping-pang HO will be caused.

0~63dBm 30

UL RX_LEVcompensati

on

Give an adjustment for the power control level value, theactual power level value MS should change is the result ofthis parameter multiply the difference between the expected

uplink signal level and the actual BTS receiving signal level.

0~100# 80#

UL Qual.Expected

The expected BTS receiving signal quality in stable status.

UL Qual.

compensation

The power adjustment value varies with this parameter. The

adjustment value caused by signal quality equal to10*difference between the expected signal quality level andthe actual receiving signal quality level times this factor.

0"100# 20#

Max PCstep

The maximum level of MS power that can be dynamicallyadjusted.

Level 1~16,2dB/level.

8


Only meanings of key parameters are listed above.


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Parameter name Meaning Valuerange

Valuerecommended

PC interval Time interval between the implementations of twopower control algorithms; unit: SACCH period

0~30 5

Filter length forInitial RX_LEV

This is the number of measurement reportsrequired for predicting the signal strength at theinitial stage. Unit: Measurement reports

1~32 2

Filter length forstable RX_LEV

This is the number of measurement reportsrequired for predicting the signal strength at thestable power control stage. Unit: Measurementreports

1-31 5

Filter length forQual.

This is the number of the measurement reportsrequired for assessing signal quality at the stablestage. Unit: Number of measurement reports

1~30 6

[MS power control table][MS power control table]



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! HW I power control judgment

" The adjustment on the current output power=(Expected signal

strength in stable status - strength of signal currently received) *

up (down) link compensating factor +[quality of uplink(downlink)

currently received - expected uplink(downlink) quality]*10*

uplink(downlink) quality compensating factor

" The final adjustment power level should be no more than the

maximum power control step size, the formula for stable level is:

stable level = currently level + the adjustment value on current

out put power



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! Power control will not occur in case of these three conditions

" Both level and quality equal to the setting values (HW I power

control), or level and quality are within threshold band(HW II

power control)

" Adjusting range less than error tolerance

" Adjusting range less than minimum power control step


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! HW I power control judgment

" Before judging the signal level to be adjusted, query the error

tolerance table according to the current transmitting power level.

Adjustment will not be done if the power adjustment value is less

than the error tolerance value.

" Error tolerance table for 900M and 1800M is as follows:


1800M:

22244433333222222222Error tolerance

191817161514131211109876543210

Level

900M

66664444444444444222Error tolerance

191817161514131211109876543210

Level

Level: Different MS transmitting power level correspond to different transmitting

power.

Error tolerance: Measured in dB, varies with MS transmitting power.

For example: The current MS is in 900M cell, with power level of 5 and error

tolerance of 4dB as listed in the sheet. BSC calculates that the power should be

increased(or reduced) 3dB, which is less than the error tolerance allowed, hence

no further power control is needed.


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! Comparison uplink and downlink of HW I power control .

" Similarity:

# 1. To avoid frequently changes of signal level, the PC interval time

between the two consecutive uplink and downlink power control are

limited.

# 2. To reduce the influence caused by abnormal reports, all

measurement reports should be filtered.

# 3. Both uplink and downlink power controls include level-specific

and quality-specific power controls.

# 4. Both uplink and downlink power controls have maximum power

control step size limit and compensating factor.



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! Comparison uplink and downlink of HW I power control .

" Differentia:

# 1. Including power control for the stable status, MS also has power

control when MS access the network, thus to reduce transmitting

power of MS as soon as possible.

# 2. For uplink, precautions are ready for increase MS transmitting

power in case HO fails.

# 3. For downlink, there are maximum and minimum transmitting

power limits in power control data configuration.



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! HW I power control exercise

" Given conditions:

# 900M MS transmitting at the maximum power, uplink receiving level

of the 900M BTS is 60dBm, uplink quality level is always 0.

# Parameter configuration in [BTS power/MS power control table] is

as follows stable RX_LEV Expected is 35, UL RX_LEV

Compensation is 80, UL Qual. expected is 1, and UL Qual.

compensation is 20, and the max. PC step is 16dB.



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" Question:

# 1. Suppose that power control will no longer be done once the

power value to be adjusted is less than 2dB, what is the

approximate stable power value after power control with the above

data configuration?

# 2. According to the error tolerance list, suppose the initial MS

transmitting power is level 3, what is the maximum uplink receiving

level in stable status after power control?

ExerciseExercise


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" Answers for question 1:

# Stable level = current actual level + [(expected signal intensity in

stable status current actual level) * uplink path loss compensating

factor] + [actual current quality expected uplink signal quality) * 10 *

uplink quality compensating factor] = -60+[(-75-(-60))*80 ]+[(0-

1)*10*20 ] = -60-12-2 -74dBm. Now its necessary to adjust -14dB

(no larger than the maximum power control step size), but it needs

further adjustment because it fails to reach -75dBm, the expected

signal level in stable status. Use -74 in the above formula again forcalculation, and the power to be adjusted is -2.8dB. Because no

power control adjustment will be done when the power value to be

adjusted is smaller than -2, it still needs to be changed 2dB lower, so

the uplink receiving level is -76dBm at last.

ExerciseExercise


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" Answers for question 2:

# Query the error tolerance table, the tolerance of level 3 is 4dB, the

power to be adjusted for the second time is 2.8, which is less than 4

and up to the requirement, so the final uplink receiving level is -

74dBm in stable status.

ExerciseExercise


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HW power control

HW power control



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! HW I I power control

" Power control algorithm implementation

" Main feature of HW I I Power control

HW I I Power ControlHW I I Power Control


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! Power control judgment process

HW I I Power Control

Measurement report pre-processing

The power control demand

according to the receiving

level

General power controljudgement

Send the power controlcommand

The power control

demand according toreceiving quality

HWII power control is performed in four steps.

1. Pre-processing of the measurement reports (interpolation and filtering),

2. Calculate power control demand according to the receiving level,

3. Calculate power control demand according to the receiving quality,

4. Make comprehensive judgment on the receiving level and receiving quality.

The same as HWI power control, measurement report pre-processing includes

interpolation and filtering. But in HWII it has compensation and forecast

functions before filtering.


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! 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.


When power control is performed based on the receiving level, it adopts three step

sizes respectively for different receiving qualities band:

MAX. Adj. Value for Qual. Zone 0 (receiving quality level 0)

MAX. Adj. Value for Qual. Zone 1 (receiving quality level 1~2)

MAX. Adj. Value for Qual. Zone 2 (receiving quality level 3~7)

The worse the quality, the shorter the allowable step size.


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! 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 receivingquality

" Adopt fixed step size when adjust the transmitting power

according to the receiving quality.


To change the transmitting power according to receiving quality, fixed step size

should be adopted --Adj. PC Value by RXqual for each receiving quality zone.


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! 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_Qul

No action % AdjStep_Qul % AdjStep_Qul

No action No action No action


Note:

1. Control as required when either level or quality needs to be controlled.

2. When the controls based on signal level and quality are in an opposite direction,

and the level requires decreasing power, so no action should be performed for

power control; when the level requires increasing power, then just perform as level

required.

3. When they work in the same direction, perform according to the larger value.


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! HW I I power control

" Power control algorithm implementation

" Main feature of HW I I Power control

HW I I Power ControlHW I I Power Control


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! HW II power control has the following advantages:

" 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


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! 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 compensation, 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.

HW II Power Control

When system makes a power control judgment, the power control module will

extract the values of receiving level and receiving quality from several history

measurement reports for filtering. In these measurement reports,MS or BTS maybe

use different transmitting power. Therefore, to ensure the accuracy of receiving

level values used for filtering, compensation should be made for receiving level

values in history measurement report whose history transmitting power is different

from the current transmitting power.


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! 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

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Power control diagram when there ismeasurement report compensation

Diagram when there is no power control

Power control diagram when there is no

measurement report compensation

Power control effect diagram of measurement report compensation

HW II Power Control


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! Measurement report prediction

" Purpose

# to 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.

HW II Power Control

After the power control module send the power control command, due to the

propagation delay and power control process delay, the transmitting power will

usually be executed after several measurement report periods. This delay will

affect the validity of power control. In order to make up some influence of power

control delay, the prediction for measurement reports should be adopted so that the

power control command will perform a little earlier.


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! Measurement report prediction

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35353535

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Yaxis

No power control

Mean filter power

control

Prediction filter power

control

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 with

mean filter

HW II Power Control


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!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).

HW II Power Control

Automatic adjustable step size:

When the power control caused by receiving level in HWII power control algorithm,

the power control will be performed also considering the receiving quality which areset into three quality zones (0, 1~2, 3). Each quality zone allow different

maximum adjustment step size. The worse the quality is, the less the adjustable

step size will be.

If the maximum step size allowed for power control is set too small, the algorithm

can not achieve the purpose of power control as soon as possible; when set it too

big, it will decrease the validity of power control.

The step size is fixed when the power should be changed according to receiving

quality.


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! Power control within the upper/lower thresholds

" As for HW II power control in case of calculating power control

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.

HW II Power Control

Configuration parameters include ([HWII power control data table]):

UL RX_LEV upper thrsh/ UL RX_LEV lower thrsh

DL RX_LEV upper thrsh/lower thrsh

UL Qual upper thrsh/lower thrsh

DL Qual upper threh/lower threh


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! Simple parameter configuration

" All needed to do is to configure simple parameters as follows:

# Signal level and quality upper/lower thresholds of up/down link

# Three kinds of step sizes for adjustment by level

# Step size for adjustment by quality

HW II Power Control

Only one sheet data needs to be configured: [HW II power control data table]


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[HW II power control table] main parameters[HW II power control table] main parameters1:1:

Parametername

MeaningValuerange

Recommended value

filter lengthfor UL

RX_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 averagedownlink quality level to be used for downlink power controladjustment.

1~20 6

MRcompensati

on 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 level

value 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.

0~3 reports 2

DL MRnumber

predicted

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

0~3 reports 2

HW II Power Control


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[HW II power control table] main parameters[HW II power control table] main parameters2:2:

Parametername

Meaning Valuerange

Recommendedvalue

PC interval Time between two power control command implementation 1~30(SACCHperiod)

5

UL RX_LEVupperthreshold

This parameter specifies the uplink signal level upper threshold.When the signal level higher than this value, calculate a powerdecrement [=receiving level - (upper threshold + lowerthreshold)/2]. This decrement value should consider together withthe maximum step size allowed for different quality zone whichthe receiving signal quality located.

0~63 35

UL RX_LEVlowerthreshold

This parameter specifies the uplink signal level lower threshold.When the signal level higher than this value, calculate a powerincrease [= (upper threshold + lower threshold)/2- receiving level].This increase also consider together with the maximum step sizeallowed for different quality zone which the receiving signal

quality located.

0~63 25

UL Qual.upperthreshold

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

0

UL Qual.lowerthreshold

This parameter specifies the uplink quality lower threshold forpower control

Level0~7

2

HW II Power Control

Note: when configuring s-strength thresholds that: upper/lower thresholds> edge

handover threshold + inter-cell handover hysteresis.

This is designed to avoid handover caused by improper power control.


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[HW II power control table] main parameters[HW II power control table] main parameters----33

Parametername

Meaning Value rangeRecommended value

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 40

DL EX_LEVlower threshold

This parameter specifies the downlink signal level lowerthreshold. When the signal level higher 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 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

HW II Power Control


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

Parametername

Meaning Value range Recommended value

max. adj. valuefor Qual. Zone

0

This parameter specifies the maximum power adj.step size allowed when adj. the power according tothe signal level when the Rx quality is 0.

0~30dB 16


1

This parameter specifies the maximum power adj.step size allowed when adj. the power according tothe signal level when the Rx quality is 1 or 2.

0~30dB 8


2

This parameter specifies the maximum power adj.step size allowed when adj. the power according tothe signal level when the Rx quality is equal to ormore than 3.

0~30dB 4

adj. PC value

by Rx Qual.

Specifying the adj. step size allowed when the

power control is adjusted according the receivingsignal quality. That is to say, the step size isconstant for power control by quality, but the stepsize varies with quality in case of power control bysignal level.

0~4dB 4

HW II Power Control


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! Exercises for HW II power control

" Given conditions:

# The uplink receiving level is -85dBm, the quality is level 4. 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 0. Uplink signal lower quality threshold:

level 2. The adjustable step size of quality band 0 is 16dB, of quality

band 1 is 8dB, and of quality 2 is 4 dB. The adjustable step size forpower control by quality is 4dB.

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

power control?

ExerciseExercise


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" Answer.

# First, transmitting power to be added according to receiving level =

(uplink signal level upper threshold + uplink signal level lower

threshold)/2-actual receiving level (-60 + (-80))/2-(-85) (-70)-(-

85) 15dB. As the receiving quality is level 4, only adjustable step

size of quality band 2 can be used -- increase 4dB.

# Second, the transmitting power to be increased according to

receiving quality = as power control adjustment step size byquality is 4dB, thus increase 4dB, the same as adjustment by

signal level.

# Therefore, according to the general judgement on power control,

4dB should be increased for adjustment either by level or by quality.

ExerciseExercise


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" Answer .

# After the implementation of step 1 power control, the receiving level

becomes: -85dBm + 4dB=-81dBm, Suppose the quality reach

already in level 2 here, it still fails within the expected band -

80dBm~-60dBm. Therefore, it needs to be adjusted.

# First: adjust by level -- repeat the previous step: adjustment by level

= (-70) (-81) = 11db, i.e. to increase 11dB. If the receiving quality

has been improved to level 2, and the adjustable step size with

quality band 1 is 8dB. Then, the result of adjustment by level is toincrease 8dB.

# Second: adjustment by quality--as the receiving quality value is

between 0 and 2, Neednt adjust.

# Therefore, the uplink stable receiving level = (-81) + 8 = -73dBm.

ExerciseExercise


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Documents

OMF010003 Power Control ISSUE1.4