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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 OverviewPower 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.
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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Power Control OverviewPower Control Overview
! 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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Power Control OverviewPower Control Overview
! 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 OverviewPower Control Overview
! 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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Power control overview
HW power control
HW power control
Course ContentsCourse Contents
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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
HW I Power ControlHW I Power Control
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
HW I Power ControlHW I Power Control
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
HW I Power ControlHW I Power Control
! 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
HW I Power ControlHW I Power Control
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
HW I Power ControlHW I Power Control
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
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HW I Power ControlHW I Power Control
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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HW I Power ControlHW I Power Control
[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.
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HW I Power ControlHW I Power Control
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]
HW I Power ControlHW I Power Control
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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
HW I Power ControlHW I Power Control
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HW I Power ControlHW I Power Control
! 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:
HW I Power ControlHW I Power Control
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.
HW I Power ControlHW I Power Control
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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.
HW I Power ControlHW I Power Control
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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.
HW I Power ControlHW I Power Control
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! HW I power control exercise
" 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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! HW I power control exercise
" 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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Power control overview
HW power control
HW power control
Course ContentsCourse Contents
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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.
HW I I Power Control
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.
HW I I Power Control
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
HW I I Power Control
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 expected receiving signal level: 30
The power control will be more effective with measurement report
compensation.
X axis
&&&&22223333444455556666777788889999&0&0&0&0
&&
&&&&
&&
&2&2&2&2
&3&3&3&3
&4&4&4&4
&5&5&5&5
&6&6&6&6
&7&7&7&7
&8&8&8&8
&9&9&9&9202020202&
2&2&
2&2222222223232323242424242525252526262626272727272828282829292929303030303&
3&3&
3&3232323233333333343434343535353536363636373737373838383839393939404040404&
4&4&
4&424242424343434344444444454545454646464647474747484848484949494950505050
0000
&0&0&0&0
20202020
30303030
40404040
50505050
60606060
70707070
Y
ax
is
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
&&&&22223333444455556666777788889999
&0&0&0&0
&&
&&&&
&&&2&2&2&2
&3&3&3&3
&4&4&4&4
&5&5&5&5
&6&6&6&6
&7&7&7&7
&8&8&8&8
&9&9&9&9202020202&
2&2&
2&2222222223232323242424242525252526262626272727272828282829292929303030303&
3&3&
3&3232323233333333343434343535353536363636373737373838383839393939404040404&
4&4&
4&424242424343434344444444454545454646464647474747484848484949494950505050
X axis
&5&5&5&5
20202020
25252525
30303030
35353535
40404040
45454545
50505050
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 expected receiving signal level: 30
The power control with prediction filter will be more effective than that with
mean filter
The expected receiving signal level: 30
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
max. adj. valuefor Qual. Zone
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
max. adj. valuefor Qual. Zone
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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! Exercises for HW II power control
" 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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! Exercises for HW II power control
" 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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