pm_sme-156_ran-02 zgf05!07!002 dynamic ms power control_v8.1.2

ZGF05-07-002 Dynamic MS Power ControlFeature Description

ZGF05-07-002 Dynamic MS Power Control


Version Date Author Approved By Remarks

V7.0.1 2008-03-18 Not open to the Third Party




ZTE Confidential Proprietary © 2008 ZTE Corporation. All rights reserved. I

© 2008 ZTE Corporation. All rights reserved.ZTE CONFIDENTIAL: This document contains proprietary information of ZTE and is not to be disclosed or used without the prior written permission of ZTE.Due to update and improvement of ZTE products and technologies, information of the document is subjected to change without notice.


TABLE OF CONTENTS

1 Feature Attribution....................................................................................................1

2 Overview....................................................................................................................12.1 Feature Introduction....................................................................................................12.2 Corelation with Other Features...................................................................................1

3 Technical Description...............................................................................................2

4 Parameters and Configurations...............................................................................34.1 Parameter List............................................................................................................34.2 Parameter Configurations...........................................................................................9

5 Related Counters and Alarms................................................................................145.1 Related Counters......................................................................................................145.2 Related Alarms.........................................................................................................15

6 Engineering Guide..................................................................................................156.1 Application Scenarios...............................................................................................156.2 Configuration Description..........................................................................................156.3 Network Influence.....................................................................................................15

7 Abbreviation............................................................................................................16

8 Reference Document................................................................................................16

FIGURES

Figure 1 Configuring Power Control Parameters 1...................................................................9Figure 2 Configuring Uplink Dynamic Power Control 2...........................................................10Figure 3 Configuring Uplink Dynamic Power Control 3...........................................................11Figure 4 Configuring Uplink Dynamic Power Control 4...........................................................12Figure 5 Configuring Uplink Dynamic Power Control 5...........................................................14

TABLES

Table 1 Parameter List............................................................................................................3Table 2 Level Values Corresponding to Uplink Signal Strength Threshold...........................12Table 3 BER Corresponding to Uplink Signal Strength Threshold.........................................12Table 4 Related counters......................................................................................................14

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1 Feature AttributioniBSC Version: [iBSC V6.20]

BTS Version: [For all BTS versions based on SDR platform]

Property: [Optional]

Related Network Elements and Requirements:NE Name Related or Not Special RequirementsMS √BTS √BSC √MSC -MGW -SGSN -GGSN -HLR -

Dependent Function: [None]

Exclusive Function: [None]

Note: [None]

2 Overview

2.1 Feature IntroductionPower control is important for spectrum efficiency as well as for power consumption efficiency in a cellular system. Dynamic MS Power Control can dynamically adjust the MS output power. The control algorithm uses the signal strength and quality information which are measured by the BTS.

Dynamic MS power control can change transmission power of mobile station (MS) within a certain range which its main purpose is to optimize transmission power of MS without affecting radio transmission quality, so as to improve spectrum efficiency and reduce MS power consumption.

2.2 Correlation with Other FeaturesThe increase uplink level threshold (PcUlInclLevThs) of MS power control should be set higher than uplink power level threshold (HUlLevThs),of uplink level based handover and the increase uplink quality threshold (PCULINCLQUALTHSThs) of MS power control should be set smaller than uplink quality level threshold (HoUlQualThs) of uplink quality

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based handover. The purpose is to enhance the level or quality of CS call as much as possible with power control before handover is triggered as the last way.

3 Technical DescriptionMS Power control is an important method for uplink radio link control. The dynamic MS power control function with parameter PwrControlUl allows MS to conduct dynamic control over the output power of MS. The transmission power of MS is adjusted according to an overall judgment based on uplink level and quality measured by BTS.

Power control should stick to the following basic principles:

Power will be decreased appropriately when the level or quality is higher than the expectation.

Power will be increased appropriately when the level or quality is lower than the expectation.

Both level and quality factors should be taken into overall consideration to make power control more accurate and effective.

MS power control consists of two phases.

At the beginning, that is, when MS and BTS start connection, BSC selects an initial transmission power for MS and BTS. When MS is connected to the network through a random access channel, its transmission power is the permissible maximum transmission power obtained in the system message broadcast on the BCCH channel of the cell where it resides. This fixed value, according to the system specifications, is also the power level of the first message sent out by MS on the dedicated channel. The MS power is not controlled by the system until the power control command carried in the SACCH message block is received, indicating the start of the second phase of MS power control, namely the regular MS power control.

In the regular MS power control phase, BTS, after receiving a certain number of uplink measurement reports, processes the measurement data to obtain the actual uplink reception level and quality and makes a comparison with the preset thresholds. Then the power level to which MS should be adjusted can be calculated. BTS sends to MS a command of changing MS power through the layer 1 header carried in each downlink SACCH message block. MS extracts power control information from the downlink SACCH and uses the transmission power specified in this information as its output power, and sets the power level in current use in the layer 1 header of the uplink SACCH and sends it together with the downlink measurement report to BSS. If the MS power level is unable to output the specified power value, it will output the power that is supported by MS and closest to the specified value.

During handover, MS uses the maximum transmission power adopted in the target cell. In the intra-cell handover, the current power is maintained.

For details about power control algorithm in technical description, please check it in the ZGF05-07-001 Dynamic BTS Power Control.

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4 Parameters and Configurations

4.1 Parameter List

Table 1 Parameter List

Full name Uplink Rapid power control indicationAbbreviation UIRapidPcInd

Description

This parameter determines the availability of the rapid power control process. Rapid power control process is an optional process of BSC. It reduces the interference of the whole BSS radio system and satisfies the dynamic power control requirement for rapid moving MS.

The amplitude of power control used by rapid power control process each time is no longer a fixed value, but an integer multiple of cell parameter power control step (increase and decrease). This parameter determines the availability of the rapid power control process.

Value Range Yes/No

Unit None

Default NoManagementObject Cell

Full name Power controlAbbreviation PwrDecrLimit

Description

This parameter is set for preventing MS from call drop due to fast power control. It corresponds to different quality level. For example, PwrDecrLimit [0] determines the maximum power decrease limit for calls with receiving quality level 0 (Bit Error rate (BER) <0.2%). This parameter is valid for both uplink and downlink.

This parameter is an array of eight elements, with element length of one byte. PwrDecrLimit [n] determines the maximum power decrease limit available for calls with quality level n. The value range of each element is 0 ~ 38 dB.

Value Range 0 ~ 38

Unit None

Default [24, 22, 20, 18, 16, 14, 12, 10]ManagementObject Cell

Full name Report period of measurement for power control Abbreviation PwrCtrlReportPrdDescription Power control is performed at BTS side and BSC implements relevant performance

statistics. BTS uses this parameter to decide the periodicity to send the preprocessed power measurement to BSC as an input for power control analysis. This parameter is in the unit of SACCH multi-frame.

Value Range 1 ~ 254Unit SACCH multiframeDefault 240ManagementObject Cell

Full name Uplink level Sample countAbbreviation PcUlLevWindowDescription In GSM system, BSC determines whether to perform power control according to



measurement data. BSC uses the average value of measurement data to avoid adverse influences caused by abrupt changes in measurement data due to complex radio transmission.

BTS uses this parameter to calculate the window size for the average value of uplink signal strength, i.e. to calculate the average value of the number of used samples.

Value Range 1 ~ 31Unit NoneDefault 6ManagementObject Cell

Full name Uplink level WeightAbbreviation PcUlLevWeightDescription Description: According to GSM Specifications, discontinuous transmission (DTX)

refers to the process in which the system does not transmit signals in the voice intermittent period during the subscriber communication process.

In the DTX mode, the measurement data reported to BSC fall into two types. One is the average of the measurement results of all timeslots in ameasurement period in the non-DTX mode, and the other is the average of the measurement results of some special timeslots in a measurementperiod in the DTX mode. BSC needs to optionally select one type of measurement data and use the data to calculate the average value.

The first type of measurement data is more accurate since it is the average value of measurement results of all timeslots. The second type of measurement data is less accurate since it is the average value of measurement results of some timeslots. Thus BSC should use different weights for the two types of data when averaging the measurement results.

This parameter determines the weight for the first type of measurement data when averaging uplink signal strength for power control. Weight for the second type of measurement data is set to 1 by default.


Full name Uplink quality Sample CountAbbreviation PcUIQualWindowDescription In GSM system, BSC determines whether to perform power control according to

measurement data. BSC uses the average value of measurement data to avoid adverse influences caused by abrupt changes in measurement data due to complex radio transmission.

BTS uses this parameter to calculate the window size for the average value of uplink signal quality, i.e. to calculate the average value of the number of used samples.


Full name Uplink quality WeightAbbreviation PcUlQualWeightDescription Description: According to GSM Specifications, discontinuous transmission (DTX)

refers to the process in which the system does not transmit signals in the voice



intermittent period during the subscriber communication process.

In the DTX mode, the measurement data reported to BSC fall into two types. One is the average of the measurement results of all timeslots in a measurement period in the non-DTX mode and the other is the average of the measurement results of some special timeslots in a measurement period in the DTX mode. BSC needs to optionally select one type of measurement data and use the data to calculate the average value.

The first type of measurement data is more accurate since it is the average value of measurement results of all timeslots. The second type of easurement data is less accurate since it is the average value of measurement results of some timeslots. Thus BSC should use different weights for the two types of data when averaging the measurement results.

This parameter determines the weight for the first type of measurement data when averaging uplink signal quality for power control.Weight for the second type of measurement data is set to 1 by default.


Full name Fast average indicationAbbreviation FastAvgDescription Network may not perform handover or power control if less measurement data is

available during call process. The average calculating process for these processes is enabled only when the measured data reaches a certain window size.

Common average process does not take place, for the five measured values BSC receives. BSC directly calculates the average of the 5 measured values if the fast average process is adopted.

There are three cases resulting in insufficient data for calculating the average value, that is, call establishment period, after handover and after power control. After performing power control once, former measured values are discarded insituations where they could result in an error control (measured values without the influence on handover control are still existing).

In addition, old measured values are discarded after the handover has occurred keeping it from causing error control (the forward and backward cells are in the same BSC).

Value Range Yes/NoUnit NoneDefault NoManagementObject Cell

Full name Increase uplink level Threshold, Value P, and Value NAbbreviation PcULInclLevThsThs/PcULInclLevThsP/PcULIncl-

LevThsNDescription According to GSM specifications, power control decisions depend upon received

average value series of uplink signal strength.

The decision process is as follows: For the latest N average values of uplink signal strength, if P of the N values fall below relevant thresholdvalue, increase MS (uplink) transmission power to improve the uplink signal quality.

Value Range Increase uplink level can be divided into four kinds: FR, HR, AMR FR, and AMR HR.Threshold: 0 ~ 63; Value P: 1 ~ 31; Value N: 1 ~ 31



Unit NoneDefault [22, 3, 4]ManagementObject Cell

Full name Decrease uplink level Threshold, Value P, and Value NAbbreviation PCULREDLEVTHSThs/PCULREDLEVTHSP/PCULREDLEVTHSNDescription According to GSM specifications, power control decisions depend upon received


The decision process is as follows: For the latest N average values of uplink signal strength, if P of the N values fall below relevant threshold value, increase MS (uplink) transmission power to improve the uplink signal strength.

Value Range Decrease uplink level can be divided into four kinds: FR, HR, AMR FR, and AMR HR.Threshold: 0 ~ 63; Value P: 1 ~ 31; Value N: 1 ~ 31


Full name Increase uplink quality Threshold, Value P, and Value NAbbreviation PCULINCLQUALTHSThs/PCULINCLQUALTHSP/PCULINCLQUALTHSNDescription According to GSM specifications, power control decisions depend upon received


The decision process is as follows: For the latest N average values of uplink signal quality, if P of the N values rise above relevant threshold value, increase MS (uplink) transmission power to improve the uplink signal quality.

Value Range Increase uplink quality can be divided into four kinds: FR, HR, AMR FR, and AMR HR.Threshold: 0 ~ 7; Value P: 1 ~ 31; Value N: 1 ~ 31


Full name Decrease uplink quality Threshold, Value P, and Value NAbbreviation PCULREDQUALTHSThs/PCULREDQUALTHSP/PCULREDQUALTHSNDescription According to GSM specifications, power control decisions depend upon received


The decision process is as follows: For the latest N average values of uplink signal quality, if P of the N values fall below relevant threshold value, reduce MS (uplink) transmission power to improve the uplink signal quality.

Value Range Decrease uplink quality can be divided into four kinds: FR, HR, AMR FR, and AMR HR.Threshold: 0 ~ 7; Value P: 1 ~ 31; Value N: 1 ~ 31


Full name Power increasing step.Abbreviation PwrIncStep_0 ~ PwrIncStep_3Description It describes increase step, the value of each power control variation. It applies to both

uplink and downlink directions.Value Range Power increase step can be divided into four kinds: FR, HR, AMR FR, and AMR HR.



Value range is 2, 4, and 6.Unit dBDefault It can be divided into four kinds: FR, HR, AMR FR, and AMR HR. 2 by default.ManagementObject Cell

Full name Power decreasing step.Abbreviation PwrRedStep_0 ~ PwrRedStep_3Description It describes decrease step, the value of each power control variation. It applies to

both uplink and downlink directions.Value Range Power decrease step can be divided into four kinds: FR, HR, AMR FR, and AMR HR.

Value range is 2 and 4.Unit dBDefault It can be divided into four kinds: FR, HR, AMR FR, and AMR HR. 2 by default.ManagementObject Cell

Full name Uplink power control allowedAbbreviation PwrControlUlDescription This parameter determines whether to enable or disable MS uplink power control in

the cell.Value Range Yes/NoUnit NoneDefault No (Set YES to activate this feature)ManagementObject Cell

Full name MS Min. TxPwrAbbreviation MSTXPWRMINDescription In the communication between MS and BTS, the transmission power is controlled by

the network. The network sets the power of MS by power command, which is transmitted on SACCH (SACCHcarries the power command with 2-header bytesinformation, one is power control byte and the other one is timing advance byte).

MS sets the specified output transmission power according to the power control header extracted from the SACCH. MS uses the nearest possible output power even if the power command sends maximum output power. During BSC power control, this parameter determines the minimum transmission power (that is, lower limit of power control) available for MS in the cell.

Value Range MIN power level of MS can be divided into four kinds: FR, HR, AMR FR, and AMR HR.Value range is 0 ~ 31.

Unit NoneDefault It can be divided into four kinds: FR, HR, AMR FR, and AMR HR. 0, 16, 0, 11.ManagementObject Cell

Full name Control channel MAX power levelAbbreviation MsTxPwrMaxCchDescription In the communication between MS and BTS, the transmission power is controlled by

the network. The network sets the power of MS by powercommand, which is transmitted on SACCH (SACCH carries the power command with 2-header bytes information, one is power control byte and the other one is timing advance byte).

MS sets the specified output transmission power according to the power control header extracted from the SACCH. MS uses the nearest possible output power even if the power command sends maximum output power.



For SACCH is Channel Associated Signaling and it has to be used together with SCCCH and TCH, so the power control of MS starts after MS receivesSACCH.

The power of MS before receiving SACCH (that is the power when sending channel request on RACH) is determined by Control channel MAX power level.

Control channel MAX power level is one of the cell selection and reselection parameters of MS, involving calculation of C1 and C2 values.

This parameter is broadcasted to all MS in the cell via RIL3_RR SYSTEM INFORMATION TYPE3 and TYPE4.

Refer to appendix C, for the maximum power before MS receives the power control information.

If this parameter is too large, the MS close to BTS will interfere with the adjacent channel; If it is too small, the MS access success rate at the edge of cell will be very low.

Setting principle: in the premise of certain MS access success rate at the cell edge, decrease the access level of MS as much as possible. Generally,it is recommended to set this parameter as 5 (for GSM900MS) and 0 (for GSM1800MS).

In practice, after setting this parameter, perform dialing test at the cell edge, increase or decrease the value of this parameter according to the MS access success rate and access time tested with different parameter setup.


Full name MS Max. TxPwrAbbreviation MsTxPwrMaxDescription In the communication between MS and BTS, the transmission power is controlled by

the network. The network sets the power of MS by powercommand, which is transmitted on SACCH (SACCH carries the power command with 2-header bytes information, one is power control byte and the other one is timing advance byte).

MS sets the specified output transmission power according to the power control header extracted from the SACCH. MS uses the nearest possibleoutput power even if the power command sends maximum output power. When BSC controls the power, the parameter is the maximum transmission power that can be used by MS in the cell. MS max power level is also a parameter used by BSC to calculate PBGT value.


Full name MIN interval of power controlAbbreviation PcMinInterval_0 ~ PcMinInterval_3Description This parameter specifies the minimum interval of power control. Usually, MS still

sends two measurement reports with the original power to BSC after enabling the power control. Signal level information contained in the reports is inaccurate and can be ignored (information such as adjacent cell information is still valid). Thus a minimum interval of power control is needed and signal level information during the



interval can be ignored.Value Range MIN interval of power control can be divided into four kinds: FR, HR, AMR FR, and

AMR HR.Value range is 1 ~ 32.

Unit SACCH multiframeDefault It can be divided into four kinds: FR, HR, AMR FR, and AMR HR. 2 by default.ManagementObject Cell

4.2 Parameter ConfigurationsEnter the configuration management interface.

1 1. In the navigation tree, click the drop-down menu of the cell to be configured, and double-click Power Control, as shown in Figure 1.

Figure 1 Configuring Power Control Parameters 1

2. Set Uplink rapid power Control Indication and Power control levels max descending value in Power control tab of Power control menu to choose whether perform Rapid power control and adopt restricting conditions of rapid power control, as shown in Figure 2:



Figure 2 Configuring Uplink Dynamic Power Control 2

Set following parameters in Power survey tab in Power control menu to choose power control decision algorithm related parameters.

Report period of measurement for power control

Uplink level sample count

Uplink level sample weight

Uplink quality sample count

Uplink quality sample weight

Parameter configuration interface is shown in Figure 3:




Set following parameters in Power Adjust Threshold tab in Power Control menu to choose power control decision criteria threshold.

Increase uplink level of FR (Ths, P and N)

Increase uplink level of HR (Ths, P and N)

Increase uplink level of AMR FR (Ths, P and N)

Increase uplink level of AMR HR (Ths, P and N)

Decrease uplink level of FR (Ths, P and N)

Decrease uplink level of HR (Ths, P and N)

Decrease uplink level of AMR FR (Ths, P and N)

Decrease uplink level of AMR HR (Ths, P and N)

Increase uplink quality of FR (Ths, P and N)

Increase uplink quality of HR (Ths, P and N)

Increase uplink quality of AMR FR (Ths, P and N)

Increase uplink quality of AMR HR (Ths, P and N)

Decrease uplink quality of FR (Ths, P and N)

Decrease uplink quality of HR (Ths, P and N)

Decrease uplink quality of AMR FR (Ths, P and N)



Decrease uplink quality of AMR HR (Ths, P and N)



Uplink received signals strength can be divided into 64 grades, ranging from 0 to 63, which are corresponding to different levels respectively. 0 refers to the lowest received signal level, 63 means the highest. Corresponding level values is shown in Table 2.

Table 2 Level Values Corresponding to Uplink Signal Strength Threshold

Threshold Level Value (dBm)0 < -110

1 -110 ~ -109

2 -109 ~ -108

… …

61 -50 ~ -49

62 -49 ~ -48

63 > -48

Uplink received signals quality can be divided into 8 grades, ranging from 0 to 7, which are corresponding to different Bit Error Ratio (BER) respectively. 0 refers to the lowest received signal BER, 7 means the highest. Corresponding BER values is shown in Table 3.

Table 3 BER Corresponding to Uplink Signal Strength Threshold

Quality BER0 BER<0.2%



1 0.2%<BER<0.4%

2 0.4%<BER<0.8%

… …

6 6.4%<BER<12.8%

7 12.8%<BER

In Others tab of Power control menu, set following parameters to choose whether to power control and adopt restricted conditions of this feature.

● FR power increasing step

● HR power increasing step

● AMR FR power increasing step

● AMR HR power increasing step

● FR power decreasing step

● HR power decreasing step

● AMR FR power decreasing step

● AMR HR power decreasing step

● Uplink power control allowed

● FR MS MAX power level of MS

● HR MS MAX power level of MS

● AMR FR MS MAX power level of MS

● AMR HR MS MAX power level of MS

● FR MS MIN power level of MS

● HR MS MIN power level of MS

● AMR FR MS MIN power level of MS

● AMR HR MS MIN power level of MS

● FR MIN interval of power control

● HR MIN interval of power control

● AMR FR MIN interval of power control

● AMR HR MIN interval of power control





If the cell supports GPRS, set Uplink power control policy in GPRS power control tab, as shown in Figure 6:

5 Related Counters and Alarms

5.1 Related Counters

Table 4 Related counters

Counter ID What It CountsC901320001 Number of normal increases of MS power due to UL signal

level

C901320002 Number of rapid increase in MS power due to UL signal level

C901320003 Number of normal decrease of MS power due to UL signal level

C901320004 Number of rapid decrease in MS power due to UL signal level

C901320009 Number of normal increases of MS power due to UL signal quality

C901320010 Number of rapid increase in MS power due to UL signal quality

C901320011 Number of normal decrease of MS power due to UL signal quality.

C901320012 Number of rapid decrease in MS power due to UL signal quality

C901320017 Total value of each result of regular scanning of MS utilization



power

C901320018 Number of regular scanning and sampling of MS utilization power

C901320023 Total value of power scans of UL signal level

C901320024 Number of power scans of UL signal level

C901320027 Total value of power scans of UL signal quality

C901320028 Number of power scans of UL signal quality

C901320029 Maximum value of UL signal level in regular scan

C901320030 Minimum value of UL signal level in regular scan

5.2 Related AlarmsNone

6 Engineering Guide

6.1 Application ScenariosThis feature suits for all scenarios.

6.2 Configuration Description This feature does not involve iBSC and BTS hardware configuration adjustment.

6.3 Network InfluenceActivation of dynamic MS power control can reduce MS transmission power with stable uplink signal strength, aiming at decreasing intra-network co-channel and adjacent-frequency interference, lowering MS power consumption.

Using dynamic MS power control with reasonable parameter setting can provide the following benefits:

Decrease intra-network co-channel and adjacent-frequency interference, improve network KPI, reduce TCH call drop, enhance handover success rate;

Lower MS power consumption;

Network element influence

This feature does not affect capacity of iBSC and BTS.



7 Abbreviation

Abbreviations Full CharacteristicsBSC Base Station Controller

BTS Base Transceiver Station

EDGE Enhanced Data rates for Global Evolution

GSM Global System for Mobile communications

GERAN Gsm/Edge Radio Access Network

MR Measure Report

MS Mobile Station

MSC Mobile Switching Centre

OMC Operation & Maintenance Center

QoS Quality of Service

SACCH Slow Associated Control Channel

8 Reference Document[1] ZXG10 BSS (V6.20.10) Radio Parameters Reference V1.0

[2] ZXG10 iBSC (V6.20.10) Performance Counter Manual V1.0

[3] ZGF05-07-001 Static BTS Power Control


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