WCDMA PS Service Optimization Guide

WCDMA PS Service Optimization Guide For Internal Use Only

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WCDMA RNP For internal use only

Product version Total 166 pages

3.2

WCDMA PS Service Optimization Guide (For internal use only)

Prepared by Yu Yongxian Date 2006-03-22

Reviewed by XieZhibin, Chen Qi, XuZili, XuDengyu, Jiao Anqiang, Hu Wensu, JiYinyu, Qin Yan, Wan Liang, and Ai Hua

Date

2006-03-22

Reviewed by Qin Yan and Wang Chungui Date 2006-03-30

Approved by

Date

Revision Records Date Version Description Reviewer Author

2004-11-26

1.00 Initial transmittal. Yu Yongxian

2006-03-09

1.01 Removing ABCD network for optimization target; putting analysis of traffic statistics in a single chapter; completing the operations and instructions at core network side by CN engineers; removing CDR part.

Yu Yongxian

2006-03-16

1.02 Moving the comparison of APP and RLC throughput to DT/CQT data analysis part; supplementing flow charts.

Yu Yongxian

2006-03-22

3.00 Changing the cover; removing BLER target and changing power control parameters; supplementing flow chats; adding an HSDPA case.

Yu Yongxian

2006-05-23

3.10 Supplementing HSDPA KPIs; adding flow for analyzing the poor performance for HSDPA to bear RAN side data in data transfer; adding analysis of interruption of data transfer for HSDPA service; supplementing HSDPA cases; revising minor errors in V3.0 guide.

Wang Dekai

2006-10-24

3.11 1 Adding analysis of throughput about lub Overbooking to R99 and HSDPA 2 adding recommendation of EPE and GBR import analysis of UE throughput. 3 Adding the third power assign methods description of HSDPA HS-SCCH and the second power assign method of baseline parameters change. 4 Adding the infection of V17 admittance arithmetic. 5 adding analysis of PLC Status Prohit Timer to RLC layer throughput. 6 Adding analysis and description of

Wang Dekai

Date Version Description Reviewer Author

APP layer throughput. 7 Adding the recommendation of V17 SET HSDPATRF commands change. 8 Modify the wrong description about TCP/IPs content.

2007-10-30

3.2 Adding some content about HSUPA Gao Bo

2008-04-17

3.21 Adding checklist of HSPA throughputs problem on back-check and orientation.

HuaYunlong

2008-10-24

3.22 Adding UMAT tools analyze HSDPAs throughput problem. Modifying some content

Hu Wensu, JiShuqi , and Fang Ming

ZhengKaisi

2008-12-18

3.23 Change the format and covert to KPI Monitoring and ImprovemnetGuilde series.

He fengming

Contents

3.1 Traffic Statistics 19 3.2 DT/CQT 20 3.3 Others 22 4.1 Traffic Statistics Indexes Related to Throughput 25 4.2 Generic Analysis Flow 29

4.2.1 Flow for Analyzing RNC-level Traffic Statistics Data 29 4.2.2 Flow for Analyzing Cell-level Traffic Statistics Data 32

5.1 Access Failure 39 5.1.1 Originating PS Service by UE Directly 39 5.1.2 UE as the Modem of PC 40

5.2 Disconnection of Service Plane 46 5.2.1 Analyze Problems at RAN Side 46 5.2.2 Analyzing Problems at CN Side 51

5.3 Poor Performance of Data Transfer 54 5.3.1 Checking Alarms 55 5.3.2 Comparing Operations and Analyzing Problem 56 5.3.3 Analyzing Poor Performance of Data Transfer by DCH 57 5.3.4 Analyzing Poor Performance of Data Transfer by HSDPA at RAN Side 62 5.3.5 Analysis of the Problem about Poor Data Transmission Performance of the HSUPA on the RAN Side 81 5.3.6 Analyzing Poor Performance of Data Transfer at CN Side 115

5.4 Interruption of Data Transfer 119 5.4.1 Analzying DCH Interruption of Data Transfer 119 5.4.2 Analyzing HSDPA Interruption of Data Transfer 121

6.1 Cases at RAN Side 124 6.1.1 Call Drop due to Subscriber Congestion (Iub Resource Restriction) 124 6.1.2 Uplink PS64k Service Rate Failing to Meet Acceptance Requirements in a Test (Air Interface Problem) 124 6.1.3 Statistics and Analysis of Ping Time Delay in Different Service Types 125 6.1.4 Low Rate of HSDPA Data Transfer due to Over Low Pilot Power 126 6.1.5 Unstable HSDPA Rate due to Overhigh Receiving Power of Data Card 127

6.1.6 Decline of Total Throughput in Cell due to AAL2PATH Bandwidth larger than Actual Physical Bandwidth 128 6.1.7 Causes for an Exceptional UE Throughput and Location Method in a Field Test 130

6.2 Cases at CN Side 133 6.2.1 Low FTP Downloading Rate due to Over Small TCP Window on Server TCP 133 6.2.2 Simultaneous Uploading and Downloading 134 6.2.3 Decline of Downloading Rate of Multiple UEs 135 6.2.4 Unstable PS Rate (Loss of IP Packets) 136 6.2.5 Unstable PS Rate of Single Thread in Commercial Deployment (Loss of IP Packets) 138 6.2.6 Unavailable Streaming Service for a Subscriber 139 6.2.7 Unavailable PS Services due to Firewall of Laptop 139 6.2.8 Low PS Service Rate in Presentation Occasion 139 6.2.9 Abnormal Ending after Long-time Data Transfer by FTP 140 6.2.10 Analysis of Failure in PS HanodverBetween 3G Network and 2G Network 144

8.1 Transport Channel of PS Data 151 8.2 Theoretical Rates at Each Layer 152

8.2.1 TCP/IP Layer 152 8.2.2 RLC Layer 152 8.2.3 Retransmission Overhead 153 8.2.4 MAC-HS Layer 153

8.3 Bearer Methods of PS Services 154 8.3.1 DCH 154 8.3.2 HSDPA 154 8.3.3 CCH 155

8.4 Method for Modifying TCP Receive Window 156 8.4.1 Tool Modification 156 8.4.2 Regedit Modification 156

8.5 Method for Modifying MTU 157 8.5.1 Tool Modification 157 8.5.2 Regedit Modification 158

8.6 Confirming APN and Rate in Activate PDP Context Request Message 159 8.6.1 Traffic Classes: 159 8.6.2 Maximum Bit Rates and Guaranteed Bit Rates 160 8.6.3 APN 160

8.7 APN Effect 162 8.7.1 Major Effect 162 8.7.2 Method for Naming APN 162 8.7.3 APN Configuration 162

8.8 PS Tools 163

8.8.1 TCP Receive Window and MTU Modification Tools 163 8.8.2 Sniffer 163 8.8.3 Common Tool to Capture Packet: Ethereal 164 8.8.4 HSDPA Test UE 164

8.9 Analysis of PDP Activation 165

Figures

Flow for analyzing RNC-level traffic statistics data 30

Flow for analyzing cell-level traffic statistics data 32

Flow for analyzing DT/CQT data 38

Flow for analyzing access failure problems when originating PS services by UE directly 39

Flow for analyzing access problem when the UE serves as the modem of PC 40

Flow for processing problem of failure in opening port 41

Flow for analyzing access failure problems 42

Signaling flow of successful setup of a PS service in Probe 43

Flow for analyzing disconnection of service plane 46

Flow for analyzing RAN side problem about disconnection of service plane for DCH bearer 47

Connection Performance Measurement-Downlink Throughput and Bandwidth window 48

HSDPA parameters in Probe 50

Flow for analyzing problems at CN side about disconnection of service plane 52

Flow for analyzing poor performance of data transfer 55

Flow for analyzing RAN side problem about poor performance of data transfer on DCH 58

Flow for analyzing data transfer affected by Uu interface 59

Flow for analyzing data transfer affected by Iub interface 61

Flow for analyzing poor performance of data transfer on HSDPA at RAN side 64

Confirming in the RNC message that PS service is set up on HSDPA channel 65

Confirming in Probe that service is set up on HSDPA channel 65

High code error of ACK->NACK/DTX in Probe 76

Uplink and downlink RL imbalance in handover areas 77

Residual BLER at MAC layer in WCDMA HSDPA Decoding Statistics window 80

Working process of an HSUPA UE 82

Optimization flow of a low throughput of the HSUPA UE 85

Confirming the service is set up on the HSUPA according to a signaling message of the RNC 86

How to confirm the service is set up on the HSUPA through the drive test tool Probe 87

RRC CONNECTION REQUEST message 90

RRC CONNECT SETUP CMP message 91

RL RECFG PREPARE message 92

Display of the Assistant HSUPA related information (limited transmit power of the UE) 93

Display of the Assistant HSUPA related information (limited traffic) 94

PHYSICAL SHARED CHANNEL RECONFIGURATION REQUEST message (containing the target RTWP and the background) 96

ATM transmission efficiency 97

P bandwidth utilization 98

RAB assignment request message (containing an MBR) 99

RL RECFG PREPARE message (containing NodeB MBR) 100

RB SETUP message (containing the maximum number of available channel codes) 101

RLC PDU retransmission rate on the Probe 109

Receiver's CPU performance observation window 113

Flow for analyzing poor performance of data transfer at CN side 116

Flow for analyzing interruption of data transfer 120

Interruption delay of TCP displayed in Ethereal 122

Variation of total throughput of one IMA link of HSDPA codes 128

Variation of total throughput of two IMA links of HSDPA codes 129

Unstable PS rate (1) 137

Unstable PS rate (2) 137

Analyzing packets captured by Ethereal upon unstable PS rate 138

Interactive interface in CuteFTP 141

Signaling of normal downloading by FTP 142

Signaling of abnormal downloading by FTP 143

Signaling of normal handover between 3G network and 2G network 145

Normal signaling flow between UE and 2G SGSN. 146

Signaling flow traced on 2G SGSN 147

Transport channel of PS data 151

Packet Service Data Flow 152

Running interface of DRTCP 157

Detailed resolution of Activate PDP Context Request message 159

Converting ASCII codes into a character string by using the UltraEdit 161

PDP context activation process originated by MS 165

Tables

Requirements by DT/CQT on PS throughput 15

Major parameters to be collected in DT/CQT 20

Tools for collecting data 22

Measured items related to PS throughput in overall performance measurement of RNC 25

Measured items related to PS throughput in cell performance measurement 26

Measured items related to HSDPA throughput (cell measurement) 27

related to HSUPA throughput (cell measurement) 27

Other measured items related to throughput 28

Indexes to judge whether a cell has PS service request 33

Cell measurement/cell algorithm measurement analysis 33

Analysis of cell performance/Iub interface measurement 34

Cell Measurement/Cell RLC Measurement Analysis 35

Comparing operations and analyzing problem 56

Relationship between CQI and TB size when the UE is in category 1112 67

Relationship between CQI and TB size when the UE is at the level 16 68

HS-SCCH power offset 71

Categories of UE HSUPA capability levels 89

PO for the E-AGCH when the Ec/Io at the edge of cells is 12 dB 103

PO for the E-RGCH when the Ec/Io at the edge of cells is 12 dB 104

PO for the E-HICH when the Ec/Io at the edge of cells is 12 dB 107

Delay test result of ping packet 126

WCDMA PS Service Optimization Guide

Key words WCDMA, PS service, and throughput

Abstract The document serves the optimization of PS service problems in large networks. It describes problem evaluation, data collection, and methods for analyzing problems.

Acronyms and abbreviations:

Acronyms and abbreviations

Full spelling

RNO Radio Network Optimization

RNP Radio Network Planning

APN Access Point Name

CHR Call History Record

CQI Channel Quality Indicator

CQT Call Quality Test

DT Driver Test

HSDPA High Speed Data Packet Access

HS-PDSCH High Speed Physical Downlink Shared Channel

HS-SCCH Shared Control Channel for HS-DSCH

QoS Quality of Service

SF Spreading Factor

UE User Equipment

SBLER Scheduled Block Error Rate

IBLER Initial Block Error Rate

HHO Hard Handover

SHO Soft Handover

NE Network Element

1. Introduction

About This Guide

The following table lists the contents of this document.

Title Description

Chapter 1 Introduction

Chapter 2 Evaluation of PS Throughput Problems

Chapter 3 Data Collection

Chapter 4 Analysis of Traffic Statistics Data

Chapter 5 Analysis of DT/CQT Data

Chapter 6 Cases

Chapter 7 Summary

Chapter 8 Appendix

In WCDMA networks, besides traditional conversational service, data service is growing with features. It has a significant perspective.

The indexes to indicate the performance of WCDMA data service includes:

Access performance It is reflected by the following indexes of data service:

Success rate of RRC setup Success rate of RAB setup Success rate of PDP activation Call drop rate of PS service Throughput Delay

There are access delay and the service interruption delay caused by HHO. This document addresses on problems in PS service optimization, such as access problems, data transfer failure, low throughput of data transfer, unstable rate of data transfer, and interruption of data transfer. It describes the method to analyze and solve DT/CQT problems. In addition, it describes the flow for processing access failure and data transfer failure problems in optimization of PS throughput.

For access problems, call drop and handover problems, see W-KPI Monitoring and Improvement Guide, which provides analysis in terms of signaling flow and performance statistics. This guide supplements the possible causes and solutions to PS service access problems in terms of operations.

This guide is for RNO in commercial network, not in benchmark trial network.

The HSDPA problem analysis and description of MML command and product function are based on the following product versions:

BSC6800V100R006C01B064 BTS3812E V100R006C02B040

When refer RRC arithmetic and product realization default is RNC V16, refer V17 it will be labeled.

The HSUPA problem analyses, description of MML command and product function are based on the following product versions:

BSC6800V100R008C01B082 DBS3800-BBU3806V100R008C01B062

2. Evaluation of PS Throughput Problems

About This Chapter

This chapter describes the evaluation of PS throughput problems.

Optimize PS throughput in terms of DT/CQT. In actual network optimization, the optimization objects and test methods are according to contract.

2 lists the requirements by DT/CQT on PS throughput.

1. Requirements by DT/CQT on PS throughput

Index

Service

Reference

Reference test method

Average downlink throughput of R99

PS UL64k/DL 64k

4856 kbps Test in the areas where Ec/Io is large than 11 dB and RSCP is larger than 90 dBm.

Test when traffic is low without call drop problems due to congestion.

Put FTP servers in CN.

Download with 5 threads.

Exclude non-RAN problems or decline of throughput caused by UE.

PS UL64k/DL 128k

96106 kbps

PS UL64k/DL 384k

300350 kbps

Average uplink throughput of R99

PS UL64k/DL 64k

4856 kbps Test in the areas where Ec/Io is large than 11 dB and RSCP is larger than 90 dBm.

Test when traffic is low (the uplink and downlink load is not larger than

Index

Service

Reference


planned load) without call drop problems due to congestion.

Put FTP servers in CN.

Download with 5 threads.

Exclude non-RAN problems or decline of throughput caused by UE.

Downlink average throughput for HSDPA single subscriber

CAT12 1.52Mbps (SBLER = 10%)

The carrier power, number of HS-PDSCH codes and Iub bandwidth resource are not restricted. The throughput is determined by capability of UE.

The average CQI of tested area is 18.

Single subscriber in unloaded conditions and in the center of cell.

760 kbps Other resources except power are not restricted.

The average

Index

Service

Reference


CQI of tested area is 10.

Single subscriber in unloaded conditions and in the edge of cell.

Throughput of HSDPA cell

CAT12 3.25 Mbps 4 CAT12 UEs, and 14 HS-PDSCH codes

It is restricted by HS-PDSCH code. The carrier power and Iub bandwidth are not restricted.


800 kbps 4 CAT12 UEs, and 14 HS-PDSCH codes

It is restricted by carrier power. The HS-PDSCH code and Iub bandwidth are not restricted.


HSUPA Single subscriber throughput

CAT3 800kbps~1.1Mbps (cell center)

Uplink RTWP, IUB bandwidth resource and UE TX power are

Index

Service

Reference


not restricted. Pilot power

33dBmRSCP>=-70dBm;

Single subscriber in unloaded conditions

Set MTU size 1500 bytes , set PDU size= 336 bits.

In UE QoS profile in HLR, MBR=2Mbps, service type is Background/Interactive

The data resource of FTP must make sure that upload can get the faster rate in the wire connection conditions.

Obtain the faster rate, combine UE capability, get APP rate in the conditions of uplink RTWP,IUB bandwidth are not restricted.

200kbps~400kbps (cell edge)

Uplink RTWP,IUB bandwidth

Index

Service

Reference


resource and UE TX power are not restricted.

Pilot power 33dBmRSCP>=-100dBm;

Single subscriber in unloaded conditions

set

MTU 1500 bytes , set PDU = 336 bits

In UE QoS profile in HLR, MBR=2Mbps, service type is Background/Interactive

The data resource of FTP must make sure that upload can get the fast rate in the wire connection conditions.

Get the fast rate , combine UE capability , get APP rate in the conditions of uplink RTWP,IUB bandwidth are not restricted.

3. Data Collection

About This Chapter

The following table lists the contents of this chapter.

Title Description

3.1 Traffic Statistics

3.2 DT/CQT

3.3 Others

There are two major methods for evaluating PS throughput: traffic statistics and DT/CQT.

1. Traffic Statistics

For collecting traffic statistics data, see W-Equipment Room Operations Guide.

2. DT/CQT

To obtain DT/CQT data, use the software Probe, UE, scanner, and GPS are involved. Obtain the information output by UE, such as:

Coverage Pilot pollution Signaling flow Downlink BLER TX power of UE

Based on the measurement tracing on RNC LMT, obtain the following information:

Uplink BLER Downlink code transmission power Downlink carrier transmission power Signaling flow at RNC side

By the DT processing software Assistant, analyze comprehensively the data collected by Probe in foreground DT and tracing record on RNC LMT.

3.2 lists the major parameters to be collected in DT/CQT.

1. Major parameters to be collected in DT/CQT

Parameter Tool Effect

Longitude and latitude Probe + GPS Record trace

Scramble, RSCP, Ec/Io of active set

Probe + UE Analyze problems

UE TX Power Probe + UE Analyze problems and output reports

Downlink BLER Probe + UE Analyze problems and output reports

Uplink/Downlink Probe + UE Analyze problems and

Parameter Tool Effect

application layer, RLC layer throughput

output reports

RRC and NAS signaling at UE side

Probe + UE Analyze problems

HSDPA CQI, HS-SCCH scheduling success rate, throughput of APP, RLC, and MAC

Probe + UE Analyze problems and output reports

Uplink BLER RNC LMT Analyze problems and output reports

Downlink transmission code power

RNC LMT Analyze problems and output reports

Single subscriber signaling tracing by RNC

RNC LMT Analyze problems

Iub bandwidth RNC/NodeB LMT Analyze problems

Downlink carrier transmission power and non-HSDPA carrier transmission power


Downlink throughput and bandwidth


Dowlink traffic RNC LMT Analyze problems

In PS service test, to reduce the impact from TCP receiver window of application layer, using multi-thread downloading tools like FlashGet is recommended. Set the number of threads to 5. For uplink data transfer, start several FTP processes.

For the detailed test and operation methods of DT and CQT, see W-Test Guide. For detailed operations on LMT, see W-Equipment Room Operations Guide.

3. Others

After finding problems by traffic statistics, DT/CQT, and subscribers' complaints, analyze and locate problems with DT/CQT and the following aspects:

RNC CHR Connection performance measurement Cell performance measurement Alarms on NEs States of NEs FlashGet DU Meter

3.3 lists the tools for collecting data.

1. Tools for collecting data

Data

Tools for collecting data

Tools for viewing/ analyzing data

Effect

Remark

Traffic statistics data

M2000 Nastar Check the network operation conditions macroscopically, analyze whether there are abnormal NEs.

For detailed operations on LMT, see W-Equipment Room Operations Guide. For usage of Nastar, see the online help and operation manual of Nastar.

DT/CQT data Probe + UE Assistant Analyze calls in terms of flow and coverage based on DT/CQT data and traced

See W-Test Guide.

Connection performance measurement,

RNC LMT Assistant or RNC LMT

See the online help of RNC LMT

Data



Effect

Remark

cell performance measurement, signaling tracing by RNC

data on RNC

Alarm M2000 or RNC LMT

M2000 or RNC LMT

Check alarms whether there are abnormal NEs

CHR RNC LMT Nastar or RNC Insight Plus

Record historic record of abnormal calls for all subscribers, help to locate problems. For subscribers' complaints, analyzing CHR helps to find the problem happening to subscribers.

None FlashGet None Downlink with multiple threads to obtain more stable throughput

Assistant tool for PS service test

None DU Meter None Observe throughput of

Assistant tool for PS service test

Data



Effect

Remark

application layer real-time, take statistics of total throughput, average throughput, and peak throughput in a period (the result is recorded by PrintScreen shot).

PS data packet Sniffer Sniffer Construct stable uplink and downlink data transmission requirement.

Used by CN engineers. For usage, see appendix.

PS data packet Ethereal Ethereal Sniff data packet at interfaces and parse data packet

Used by CN engineers. For usage, see appendix.

Note: CHR is called CDL in those versions prior to RNC V1.6. CHR is used in these versions after V1.6.

When analyzing data with previous tools, engineers need to combine several data for analysis. For example, in network maintenance stage, if some indexes are faulty, analyze some relative data such as performance statistic, alarm data, and CHR. According to the level of problems, perform DT/CQT in cell coverage scope; trace the signaling of single subscriber and conduct connection performance measurement on RNC LMT.

If there are problems in DT/CQT, analyze them based on traffic statistics and alarms.

4. Analysis of Traffic Statistics Data

About This Chapter

This chapter analyzes traffic statistics data.

Title Description

4.1 Traffic Statistics Indexes Related to Throughput

4.2 Generic Analysis Flow

The access, call drop, SHO, HHO, inter-RAT handover problems may affect throughput of PS services. Therefore, before analyzing and optimizing throughput of PS services, analyze access, call drop, SHO, HHO, inter-RAT handover problems.

To analyze access problems and traffic statistics indexes, see W-Access Problem Optimization Guide.

To analyze handover and call drop problems, and traffic statistics indexes, see W-Handover and Call Drop Problem Optimization Guide.

1. Traffic Statistics Indexes Related to Throughput

The following four tables are based on RNC V1.6.

4.1 lists the measured items related to PS throughput in overall performance measurement of RNC.

1. Measured items related to PS throughput in overall performance measurement of RNC

Measured item

Major indexes Effect

Overall performance measurement of RNC/RLC statistics measurement

RLC buffer size

Average utilization of buffer

Number of data packets sent and received by RLC in TM/AM/UM mode

Number of data packets dropped by RLC

Number of retransmitted data packets

Check whether the RLC buffer is inadequate

Check the probability of dropping data packets by RLC

Or whether the downlink retransmission rate is over high

Overall performance measurement of RNC/UE state

Number of UEs in CELL_DCH, CELL_FACH, CELL_PCH, and URA_PCH state

Serve as reference for understanding traffic model of subscribers

Measured item


measurement

Overall performance measurement of RNC/RB measurement

Number of conversational service, streaming service, interactive service, and background service in various uplink and downlink rates in PS domain under RNC

Times of abnormal call drops for previous services in various rate in PS domain

Analyze the number of subscribers using different services at different rate;

Analyze the call drop problems of various rate

Overall performance measurement of RNC/RNC traffic measurement

Uplink and downlink traffic (RLC layer excludes traffic of RLC header) of all services in PS domain under RNC

Overall performance measurement of RNC/PS inter-RAT handover measurement

Times of successful/failure PS inter-RAT handovers

The failure causes

Frequent inter-RAT and the call drop due to it will directly affects PS service subscribers' experiences. Guarantee high handover success rate by analyzing and optimizing the measured item while avoid ping-pong handover. Reduce the impact from inter-RAT handover on PS throughput.

4.1 lists the measured items related to PS throughput in cell performance measurement.

2. Measured items related to PS throughput in cell performance measurement

Measured item


Cell measurement/traffic measurement

Uplink and downlink traffic volume (number of MAC-d PDU bytes) at Iub interface, traffic of RACH, FACH, and PCH; Iub CCH bandwidth

Analyze whether the CCH is to be congested; take statistics of Iub TCH traffic

Cell measurement/cell algorithm measurement

DCCCC and congestion control Analyze cell congestion problems and rationality of DCCC parameters

Cell measurement/cell RLC measurement

Collect cell level data ,such as: Valid RLC

data rate Downlink service

Number of signaling PDUs

Number of retransmitted PDUs

Number of discarded PDUs

Take statistics of valid data rate at RLC layer

The transmission rate of service and signaling

The dropping rate

Cell measurement/cell throughput of

Average throughput and volume of various service

Obtain the average throughpu

various services, throughput t measurement

t of various services in the cell.

Judge whether the average throughput meets the optimization objectives

Cell measurement/BLER measurement of various services in cell

Uplink average BLER of various services in cell

The ratio of time of maximum value of BLER

Cell measurement/Iub interface measurement

Number of requested RLs at Iub interface

Number of successful RLs

Number of failed RLs,

Different causes of failures

Check the resource allocation condition at Iub interface whether Iub is congested.

In cell performance measurement, HSDPA part is added, and other indexes are the same as that of R99. Some traffic statistics indexes corresponding to HSDPA services are not added to RNC traffic statistics.

Table 4-3 lists the measured items related to HSDPA throughput (cell measurement).

3. Measured items related to HSDPA throughput (cell measurement)

Measured item


Cell measurement/HSDPA service measurement

Statistics of HSDPA service setup and deletion

Number of HSDPA subscribers in cell

D-H, F-H transition

Serving cell update

Intra-frequency HHO

Inter-frequency HHO

MAC-D flow throughput

Know the HSDPA throughput and number of subscribers in cell

Table 4-4 lists the measured items related to HSDPA throughput (cell measurement).Measured items

4. related to HSUPA

throughput (cell measurement)

Measured item



Measured item HSUPA.CELL include the PI of service setup , release and the number of EDCH handover

Know the HSUPA throughput and number of subscribers in cell

Table 4-5 shows other measured items related to throughput.

5. Other measured items related to throughput

Measured item

Major indexes

Effect

Performance measurement at Iu interface

Iu-PS reset times, setup and release times, and overload control times.

Analyze whether lu-PS interface is normal

GTP-U measurement

Number of bytes sent and received by GTP-U

Determine the scope of problems by comparing RLC layer traffic and GTP-U traffic

Distinguish RAN side problems from CN side problems

UNI LINK Average receiving and sending rate of

measurement UNI LINK

IMA LINK measurement

Average receiving and sending rate of IMA LINK

IMA GROUP link measurement

Average receiving and sending rate of IMA GROUP

2. Generic Analysis Flow

According to 4.1, the indexes related to PS throughput include:

Overall performance measurement of RNC Cell measurement Performance measurement at Iu interface GTP-U measurement UNIUNI LINK measurement IMA LINK measurement IMA GROUP link measurement

Analyzing traffic statistics data is mainly based on overall performance measurement of RNC and cell measurement. Analyzing RNC-level data addresses on evaluating and analyzing performance of entire network. Analyzing cell-level data addresses on locating cell problems. Other measured items like Iu interface and transmission help engineers to analyze problems in the whole process of performance data analysis.

In actual traffic statistics analysis, evaluate the indexes of entire network and then locate cell-level problems.

1. Flow for Analyzing RNC-level Traffic Statistics Data

Figure 4-1 shows the flow for analyzing RNC-level traffic statistics data.

1. Flow for analyzing RNC-leveltrafficstatistics data

The RNC traffic statistics indexes of current version do not include statistics of throughput of various services, but include RNC traffic volume measurement. The traffic volume measurement is relevant to subscribers' behaviors and traffic model.

The traffic volume is not the same every day, but is fluctuating periodically from Monday to Saturday and Sunday. Therefore, upon analysis of RNC traffic volume, observe the fluctuation of weekly traffic volume. For example, compare the curve chart of traffic volume for a weak with that of last weak. If they are similar, the network is running normally according to RNC-level analysis. If they are greatly different from each other, analyze the problem in details.

When analyzing problems, check whether the RNC-level traffic statistics indexes are normal in synchronization, such as RB, RLC, Iu interface. Then follow the flow for analyzing cell-level traffic statistics data.

If the PS throughput of one or two cells is abnormal, this cannot be reflected by RNC-level traffic statistics. Therefore, analyzing cell-level traffic statistics data is necessary even if RNC-level traffic statistics is normal.

2. Flow for Analyzing Cell-level Traffic Statistics Data

1. Flow for analyzingcell-leveltrafficstatistics data

The cell-level traffic statistics data is obtainable from cell measurement/cell throughput of various services, and volume measurement, including the average throughput and total volume of various services.

Select a representative service in the network, or a continuous coverage service. Analyze the average throughput of each cell for the selected service by Nastar and sort the cells by cell throughput. Select the top N worst cells for analysis.

The cells with 0 PS RAB setup request is excluded from sorting alignment, namely, the total number of the four indexes listed in 4.2.2 is 0. Such cells are considered as having no PS service request, so they are excluded from sorting alignment the worst cells for PS throughput.

1. Indexes to judge whether a cell has PS service request

Measured item

Type Index

Cell measurement Number of successful RABs with RAB assignment setup in PS domain in cell

VS.RAB.AttEstabPS.Conv VS.RAB.AttEstabPS.Str VS.RAB.AttEstabPS.Inter VS.RAB.AttEstabPS.Bkg


Times of HSDPA service setup requests in cell

VS.HSDPA.RAB.AttEstab

For the worst cell, check that they are not with access, call drop, and handover problems. Then analyze the cell performance from cell measurement/traffic measurement, cell measurement/cell algorithm measurement, and cell measurement/cell RLC measurement.

14.2.2 describes the cell measurement/cell algorithm measurement analysis.

2. Cell measurement/cell algorithm measurement analysis

Index Meaning

Analysis

Solution

VS.LCC.BasicCongNumUL VS.LCC.BasicCongNumDL

Times of uplink and downlink basic congestion in cell

If one of them is large than 0, the cell is with basic congestion problem

If the load of inter-frequency cells with overlapped coverage is low, optimize load balance parameters. Otherwise consider adding carriers.

VS.LCC.OverCongNumUL VS.LCC.OverCongNumDL

Times of cell congestion due to uplink and downlink overload

If one of them is large than 0, the cell must be badly congested

If the load of inter-frequency cells with same coverage is low, optimize load balance parameters. Otherwise consider adding carriers.

VS.DCCC.D2D.SuccRateDown.UE VS.DCCC.D2D.SuccRateUp.UE

Times of successful configuration of DCH dynamic channel with decreasing downlink rate in cell

If the average service throughput is much lower than the bandwidth, the DCCC algorithm parameter may be irrational.

Confirm the DCCC algorithm parameter

VS.Cell.UnavailTime.OM Length of unavailable time

If it is large than 0, the cell must have been

Check alarms and CHR for causes of system

of cell unavailable. abnormalities

24.2.2 describes the analysis of cell performance/Iub interface measurement.

3. Analysis of cell performance/Iub interface measurement

Index Meaning

Analysis Solution

VS.IUB.AttRLSetup VS.IUB.SuccRLSetup

Number of requested RLs set up at lub interface in cell. Number of successful RLs set up at lub interface in cell.

If SuccRLSetup

In cell measurement/traffic measurement analysis, take statistics of traffic at MAC layer.

Take statistics of traffic flow, signaling flow, FACH/RACH/PCH transport channel flow, and Iub CCH bandwidth.

If the total service throughput approaches available Iub bandwidth of TCH, the throughput may declines due to inadequate Iub bandwidth. Solve this problem by adding transmission bandwidth.

4) 4.2.2 describes Cell Measurement/Cell RLC Measurement Analysis

4. Cell Measurement/Cell RLC Measurement Analysis

Index Meaning

Analysis

Solution

VS.RLC.AM.TrfPDU.Trans Number of PDUs sent by RLC in AM mode

Check the power control parameters like target value of service BLER, transmission error rate, and clock abnormality. Check coverage.

VS.RLC.AM.TrfPDU.Retrans Number of service PDUs retransmitted by RLC in downlink in AM mode

Service retransmission rate = number of PDUs for retransmission service/number of sent service PDUs. If the retransmission rate is high, there may be some problems.

VS.AM.RLC.DISCARD.TRF.PDU

Number of service PDUs dropped by RLC in downlink in AM mode of cell

Dropping rate = number of dropped service PDUs/number of sent service PDUs. If the PDU drop rate is high, there may be some problems.

VS.RLC.AM.SigPDU.Trans Number of signaling PDUs sent by RLC in AM mode

Check the power control parameters like target value of service BLER, transmission error rate, and clock abnormality. Check coverage.

VS.RLC.AM.SigPDU.Retrans Number of signaling PDUs retransmitted by RLC in downlink in AM mode

Signaling retransmission rate = number of retransmitted signaling PDUs/number of sent signaling PDUs

VS.AM.RLC.DISCARD.SIG.PDU

Number of signaling PDUs dropped by RLC in downlink in AM mode of cell

Signaling dropping rate = number of dropped signaling PDUs/number of sent signaling PDUs

The causes of high RLC retransmission rate and PDU packet dropping rate are:

Bad BLER of radio link (including weak coverage) High transmission error rate Clock abnormality

To confirm weak coverage problem, perform DT/CQT and analyze CHR as below: Perform DT/CQT to know the overall coverage conditions Analyze CHR to know the RSCP and Ec/Io of subscribers in the environment Sort the subscribers by RSCP in CHR analysis Record the worst N subscribers and visit the location Perform DT/CQT accordingly in these locations

5. Analysis of DT/CQT Data

About This Chapter

The following table lists the contents of this chapter.

Title Description

5.1 Access Failure

5.2 Disconnection of Service Plane

5.3 Poor Performance of Data Transfer

5.4 Interruption of Data Transfer

WCDMA PS service data transfer problems include the following three types in terms of phenomena:

Access failure (or dial-up connection failure) Successful access but unavailable data transfer Available data transfer but low speed or great fluctuation

For the problem with different phenomena, follow different flows for processing them.

1. Flow for analyzing DT/CQT data

For access, call drop, signaling plane, and handover problems, see W-Access Problem Optimization Guide and W-Handover and Call Drop Problem Analysis Guide. This guide supplements some operations in PS service test.

1. Access Failure

There are two ways to use PS services:

Originating PS services directly on UE, browsing web pages, and watching video streaming directly on UE

Combining personal computer (PC) and UE. Namely, UE serves as the modem of PC, and the service is originated through PC

In optimization test, the combination of PC and UE is most widely used. In DT/CQT, the PC is usually a laptop with the DT software Probe installed on it. This is called Probe + UE. When the UE fails to directly originate PS services, it can obtain more information by using Probe + UE. Therefore, the following analysis is mainly based on Probe + UE.

1. Originating PS Service by UE Directly

5.1.1 shows the flow for analyzing access failure problems when originating PS services by UE directly.

2. Flow for analyzingaccessfailureproblemswhenoriginating PS services by UE directly

The signaling of originating PS services by UE directly is the same as that of PC + UE. The difference lies in the access point name (APN), and the way to set the address for service visiting. If the UE fails to originate PS services directly, following the step below for analyzing causes:

Verify the problem by PC + UE If the PS services through PC + UE are normal, the system must work normally. Then check and modify the APN, address for serving visiting, Proxy, and password set on UE.

Follow 5.1.2 if originating PS services by PC + UE fails.

2. UE as the Modem of PC

5.1.2 shows the flow for analyzing access problem when the UE serves as the modem of PC.

1. Flow for analyzingaccessproblemwhen the UE serves as the modem of PC

Failure in Opening Port

5.1.2 shows the flow for processing problem of failure in opening port.

2. Flow for processingproblem of failure in opening port

The major causes to failure in opening port include: Port in Hard Config of Probe is incorrectly configured

Check the configuration in Hardware Config. The port must be consistent with the Com port and Modem port in Device Manager in Windows operating system.

The port state is abnormal The driver is improperly installed. Or during DT, the DT tool may abort abnormally, so the port mapped in Windows Device Manager is marked by a yellow exclamatory mark. To solve this problem, reinstall the driver, pull and plug data line or data card of UE.

After the software aborts abnormally, the port is not deactivated The DT software like Probe may abort abnormally, so the corresponding port is improperly closed. To solve the problem, quit the Probe and restart it. If the problem is still present, restart PC.

The software of UE is faulty Restart UE to solve the problem.

The driver of UE is incompletely installed Reinstall the driver. This problem usually occurs upon the first connection of PC and UE.

Successful Activation of Port but Access Failure

Opening port succeeds, but access fails. This is probably due to signaling flow problem.

5.1.2 shows the flow for analyzing access failure problems

3. Flow for analyzingaccessfailureproblems

Trace the NAS and RRC signaling in Probe or trace the signaling of single subscriber on RNC LMT. Analyze the problem by comparing it to the signaling flow for standard data service. For the signaling flow for standard data service, see the senior training slides of RNP: W-RNP Senior Training-Signaling Flow.

5.1.2 shows the signaling flow of successful setup of a PS service in Probe.

4. Signaling flow of successful setup of a PS service in Probe

In 5.1.2, Probe contains two windows: RRC Message, and NAS Messages. The signaling point in NAS Messages window corresponds to the point of direct transfer messages in RRC Message.

The following problem may occur due to the comparison of signaling flow:

RRC connection setup failure Description: in 5.1.2 , it is abnormal from the RRC Connection Request message to the RRC Connection Setup Complete message. Analysis: the UE fails to send the RRC Connection Request message according to the RRC Messages window in Probe, probably due to:

Modem port is not selected in the Hardware Config widow in Probe. Test Plan is not configured in Probe or improperly configured. The port of UE is abnormal. See the Failure in Opening Port in 5.1.2for

solution. After the UE sends the RRC Connection Request message, it receives no response or receives RRC Connection Reject message due to the

admission rejection caused by weak coverage and uplink and downlink overload. For details, see the section Analyzing RRC Connection Setup Problems in W-KPI Monitoring and Improvement Guide.

UE's failure in sending Service Request Description: There in no Service Request message in NAS Messages. Analysis: The UE may have disabled PS functions or may have not registered in PS domain.

The UE may have disabled PS functions. Some UE supports CS or PS, or CS + PS. If the UE is set to support CS, PS services will be unavailable on it. Check the UE configuration and Set it to support PS or CS + PS.

The UE may have not registered in PS domain. According to signaling flow, after the UE sends the Attach Request message, the network side responds the Attach Reject message. The engineers at CN side need to check whether the USIM supports PS services.

The flow for authentication and encryption is abnormal Description: it is abnormal from the Authentication AND Ciphering REQ in NAS messages to the Security Mode Complete in RRC messages. Analysis: the engineers at CN side need to check whether the authentication switch in PS domain of CN is on, whether the CN CS domain, PS domain, encryption algorithm of RNC, and the integrity protection algorithm is consistent. On RNC LMT, query the encryption algorithm by executing the command LST UEA. Query the integrity protection algorithm by executing the command LST UIA. For details, see the section Analyzing Authentication Problems and the section Analyzing Security Mode Problems in W-KPI Monitoring and Improvement Guide.

PDP activation is rejected Description: after the UE sends the Activate PDP Context Request message, it receives the Activate PDP Context Reject message. Analysis: there are two types of problems, the improper configuration of APN and rate at UE side, or CN problems.

Improper APN at UE side If the cause value of Activate PDP Context Reject is Missing or unknown APN, the APN configuration is probably inconsistent with CN side. Check the Probe and APN at UE side, and compare them with HLR APN. For the method to set APN of UE and Probe, see the section Connecting Test Device in Genex Probe Online Help. Ask the CN engineers to check the APN in HLR.

Improper rate at UE side

If the cause value of Activate PDP Context Reject is Service option not supported, the requested rate of UE is probably higher than subscribed rate in HLR. Check the requested rate at Probe and UE side, and compare them with the subscribed rate in HLR. Ask the CN engineers to check the subscriber rate in HLR. Check the APN and requested rate in the Activate PDP Context Request message. See the appendix 8.6.

CN problem If the APN at UE side and restricted rate are properly configured, the problem is probably due to CN problem. If some interfaces of CN are unavailable, locate the problem with engineers on PS domain of CN. If the PS service is the initial commissioning, the APN for defining a subscriber by HLR is inconsistent with that of gateway GPRS support node (GGSN). Confirm this with engineers on PS domain of CN. For the analysis of causes of PDP activation rejection, see 8.9.

RB setup failure Description: after Activate PDP Context Request, the system fails to receive Radio Bearer Setup message, but receives the release message. Analysis: for details, see the section Analyzing RAB or RB Setup Problems in W-KPI Monitoring and Improvement Guide.

Others See 5.3.2. Shrink the scope of the problem by changing each device.

2. Disconnection of Service Plane

5.2 shows the flow for analyzing disconnection of service plane, though the PS service setup succeeds.

1. Flow for analyzingdisconnection of service plane

1. Analyze Problems at RAN Side

The connection setup succeeds, so the signaling plane is connected but the service plane is disconnected. This is probably due to TRB reset at RAN side. For HSDPA, the service is carried by HS-PDSCH and the signaling is carried by DCH. When the power of HS-PDSCH is inadequate,

probably the signaling plane is connected and service plane is disconnected. The following sections distinguish PS services carried on DCH from PS services carried on HSDPA.

DCH bearer

5.2.1 shows the flow for analyzing RAN side problem about disconnection of service plane for DCH bearer.

2. Flow for analyzing RAN sideproblem about disconnection of service plane for DCH bearer

Check coverage conditions

Trace the pilot RSCP and Ec/Io of serving cell by Probe + UE. Judge whether a point is in weak coverage area. For weak coverage area, such as RSCP < 100 dBm or Ec/Io < 18 dB, the data transfer for PS services is probably unavailable. Solution: If the RSCP is bad, optimize it by improving coverage quality. If the RSCP is qualified, but Ec/Io is bad, check:

Pilot pollution. Then optimize the serious pilot pollution. Power configuration of pilot channel (LST PCPICH), usually 33 dBm. There is no external interference

Check call drop problem due to TRB reset

Obtain the CHR files corresponding to the occurrence point of problem. On RNC LMT or in Nastar, check whether there is abnormal information near the point of problem occurrence. This provides the evidence for judgment. For the analysis tool, see W-KPI Monitoring and Improvement Guide.

Trace uplink and downlink throughput and bandwidth

On RNC LMT, select Connection Performance Measurement > Uplink Throughput and Bandwidth, Downlink Throughput and Bandwidth. For details, see the online help for RNC LMT. Check the uplink and downlink throughput and bandwidth. 5.2.1 shows the Connection Performance Measurement-Downlink Throughput and Bandwidth window.

3. Connection Performance Measurement-DownlinkThroughput and Bandwidthwindow

In 5.2.1, The bandwidth shown is the bandwidth assigned for UE by system. The DLThroughput is the actual throughput of downlink data transfer.

Monitor the variation of access layer rate and non-access layer rate of uplink and downlink data transfer for the current connection. This helps analyze the functions of dynamic channel configuration and variation features of service source rate.

If the uplink throughput is 0, the uplink may be disconnected. If the downlink throughput is 0, the downlink may be disconnected.

When the RNC DCCC function is valid, distinguish the variation of bandwidth caused by DCCC. If the problem is still not located after previous operations, collect the data packets received and sent at RNC L2 and by GTPU by using the tracing tool RNC CDT. This helps judge whether the disconnection of subscriber plane is in uplink or downlink, at CN side or RAN side.

Further

Check problems at the CN side according to analysis of problems at CN side in 5.2.2. Refer to Comparing Operations and Analyzing Problem. Change each part and compare the operations. This helps reduce the scope of the problem. Feed back the problem.

HSDPA Bearer

The HSDPA feature of cell is activated, The UE supports HSDPA. The rate requested by UE or the subscribed rate is higher than HSDPA threshold for downlink BE service (for BE service) or HSDPA threshold for downlink streaming service (for streaming service). When the PS services are carried by HSDPA, follow the steps below:

Alarms in RNCs and CHR

Check the alarms and CHR for the point of problem occurrence whether there are abnormalities. Provide diagnosis.

Deactivate HSDPA features so that PS services are set up on DCH

Deactivate HSDPA features by executing the command DEA CELLHSDPA. Connect UE to the network by dial-up so that PS services are set up on DCH. If the data transfer is unavailable on DCH, see the troubleshooting in previous block DCH Bearer. If the data transfer is available on DCH, the problem must be about HSDPA. Follow the steps below.

Check the CQI, HS-SCCH success rate, and SBLER

Check the CQI, HS-SCCH success rate, and SBLER by Probe + UE as below:

CQI The UE estimates and reports CQI based on PCPICH Ec/Nt. If the CQI reported by UE is 0, the NodeB will not send UE any data. In the current version, if the CQI calculated by NodeB based on current available power is smaller than 2, the NodeB will not schedule the UE and send it any data. If the common parameters like pilot Ec/Io, CellMaxPower, PcpichPower, and MPO are normal, but the CQI is bad, change a PC. The PCs of different types have different thermal noises, so they have different impact on reported CQI.

HS-SCCH success rate The HS-SCCH success rate is obtainable in the WCDMA HSDPA Decoding Statistics window and WCDMA HSDPA Link Statistics window, as shown in 5.2.1.

4. HSDPA parameters in Probe

Wherein, the HS-SCCH Success Rate (%) is the HS-SCCH scheduling success rate of the UE. It is relevant to the following parameters:

Number of HS-SCCHs Number of HSDPA subscribers Scheduling algorithm parameter

If an HS-SCCH is configured to the HSDPA cell, the scheduling algorithm is the RR algorithm, and all the connected subscribers keeps data transfer, the HS-SCCH success rate is the reciprocal of number of subscribers. Namely, all the subscribers share the HS-SCCH resource. If the HS-SCCH success rate of a subscriber approaches 0, the data transfer rate of the subscriber approaches 0, and the service plane may be disconnected. The HS-SCCH success rate approaches 0 due to:

The scheduling algorithm is much similar to MAX C/I algorithm, more than one HSDPA subscribers connects to the cell, and the CQI of the subscriber is low.

The transmit power of HS-SCCH is over low. Now in the indoor scenario, the transmit power of HS-SCCH is fixed to 2% of total transmit power of cell. In outdoor scenarios, the proportion is 5%. If the transmit power of HS-SCCH is lower than the fixed power, the UE may fail to demodulate HS-SCCH data.

No data is transmitted at the application layer. Confirm this by the actual transmitted data volume in the Connection Performance Measurement-Uplink Throughput and Bandwidth, Downlink Throughput and Bandwidth on RNC LMT.

The CQI reported by UE is over low, so the NodeB will not schedule the subscriber.

SBLER being 100% The SLBER is the slot block error rate of HS-DSCH. In 5.2.1, the right pane of the WCDMA HSDPA Decoding Statistics window shows the SBLER and retransmission conditions of transport blocks of different sizes. The WCDMA HSDPA Link Statistics window shows the following parameters:

HS-DSCH SBLER-Deta HS-DSCH SBLER-Average

Wherein, the Delta is the instantaneous value. The Average is the average value. When the HS-PDSCH Ec/Nt is over low, the SBLER will be 100%. This is actually caused by inadequate HSDPA power. Check the HSDPA power configuration by executing the command LST CELLHSDPA. Wherein, the HS-PDSCH and HS-SCCH power are the HSDPA power configuration.

There are two methods for HSDPA power configuration: static power configuration and dynamic power configuration.

If the power of the parameter configuration is higher than or equal to the maximum transmit power of cell, use dynamic power configuration.

If the power of the parameter configuration is lower than the maximum transmit power of cell, use static power configuration.

The available power of HS-PDSCH in static power configuration = maximum transmit power of cell power margin R99 downlink load (including CCH load) HS-SCCH power. The available power of HS-PDSCH in dynamic power configuration = power of HS-PDSCH and HS-SCCH HS-SCCH power. Note the static power configuration. Due to power control, the R99 services can use HS-PDSCH power. According to previous two formulas, in dynamic power configuration of HSDPA power, if the power margin is over large, R99 downlink load is over high, or HS-SCCH power is over high, the available power of HS-PDSCH is over low. In static power configuration of HSDPA power, if the HS-PDSCH and HS-SCCH power are over low, or HS-SCCH power is over high, the available power of HS-PDSCH is over low. SBLER is 100% seldom due to inadequate power, unless the CQI reported by UE is over small. When the power of NodeB is inadequate, the CQI calculated by NodeB is smaller, the scheduled TB blocks becomes smaller, so the rate obtained by UE declines. Solution: adjust parameter configuration. If the R99 load is over high, add carriers.

Check the available bandwidth, occupied bandwidth, and assigned bandwidth at Iub interface

Query Iub bandwidth by executing the command DSP AAL2PATH on RNC LMT. Or start the task Periodic Reporting of Iub Bandwidth Assignment Conditions of HSDPA on NodeB console. If errors occur in data transmission, the IMA group number of AAL2PATH (For HSDPA) on NodeB fails to match that on RNC. When the available bandwidth of HSDPA is inadequate due to product software problems, the data transfer is unavailable.

2. Analyzing Problems at CN Side

The problems at CN side include abnormal work state of service servers and incorrect user name and password.

5.2.2 shows the flow for analyzing problems at CN side about disconnection of service plane.

1. Flow for analyzingproblemsat CN side about disconnection of service plane

Confirm by other access network or LAN that the service software servers and service software run normally.

LAN

Use FTP or HTTP service on a PC connected to LAN, and check whether the service is available. In addition, verify the user name and password of the connected user.

Other radio access network under the same CN If different 3G access networks under the same CN sets up PS service or sets up PS service from the GRPS network, check whether the service is normal.

After previous checks, if the service servers work normally, focus on the problems at RAN side for analysis. If the service servers are abnormal according to previous checks, ask the on-site engineers of CN PS domain to solve the problem.

The IP address for visiting FTP and HTTP service servers by LAN is different from that for visiting service servers after the UE sets up wireless connection. For details, turn to on-site engineers of CN PS domain.

3. Poor Performance of Data Transfer

The poor performance of data transfer, in terms of throughput measurement, lies in the following problems:

Unstable rate like great fluctuation Low rate

The poor performance of data transfer, in terms of QoS, lies in the following problems: Unclear streaming image Buffering Low rate in browsing web pages

The appendix 8.1contains the transport path of PS data. The PS data passes Internet service servers, GGSN, SGSN, RNC, NodeB, and finally UE. Meanwhile the PS data passes Gi, Gn, IuPS, Iub, and Uu interfaces. During the process, the PS data passes Internet servers to GGSN using IP protocol. Between them, there may be one or more devices like router and firewall.

The PS services use the AM mode of RLC and support retransmission function. The FTP and HTTP services use TCP protocol which supports retransmission. The parameters of these two protocols (RLC/TCP) have great impact on rate. If the parameter configuration is improper, or missing and dropping data packet may cause the data rate to decline. When checking the quality of service (QoS), engineers make UE as the modem of a computer running applications, so the performance of computer and servers will influence the QoS. By and large, several factors affect the performance of data transfer of PS services, and they include:

RAN side CN equipment Applications and service software

The applications and service software problems are contained in the CN side problems. 5.3 shows the flow for analyzing poor performance of data transfer.

1. Flow for analyzingpoor performance of data transfer

1. Checking Alarms

If there is a problem, check whether there are alarms. Query the NodeB and RNC alarms at RAN side. Query the SGSN, GGSN, LAN switch, router, and firewall at CN side. The alarms like abnormal clock alarms, high transmission error rate, and abnormal equipment affect data transfer.

If problems cannot be located according NE alarms, refer to 5.3.2. By comparing operations and analyzing problem, reduce the scope of problem.

If the problem is at RAN side, refer to 5.3.3.

If the problem is at CN side, refer to 5.3.6. If the problem concerns both the RAN and CN side, analyze it from both

sides.

2. Comparing Operations and Analyzing Problem

Compare operations and analyze problem to focus on the possible faulty NE and to determine the scope of problem: at CN side and service software, or at RAN.

1. Comparing operations and analyzing problem

Order Operation Result Analysis

1 Change USIM card Data transfer problem has been solved

Problem maybe related to user information configured in the USIM card.

Data transfer problem is still unsettled

The problem cannot be located, so continue checks.

2 Change UE/data card Data transfer problem has been solved

Related to UE, such as incompatibility and poor performance of UE



3 Change PC Data transfer problem has been solved

Related to drivers, APN, restricted rate, and firewall.

Data transfer problem is still

The problem cannot be located, so


unsettled continue checks.

4 Change PC under the same server (ensure than the service is running normally, and try to PING the server and use streaming services.

Data transfer problem has been solved

The problem at CN side, related to service software



5 Change a new website for visiting (from other websites)


The problem at CN side, related to performance of server, TCP/IP parameters, or service software



6 Change other access network under the same server, such as GPRS network


The problem at RAN side.


The problem cannot be located.

7 Test on other NodeBs


The NodeB problem, or improper configuration of parameters related to the NodeB and configured by RNC

Data transfer The problem cannot


problem is still unsettled

be located.

After the approximate scope of problem cannot be located after previous checks, analyze it as a problem of data transfer at RAN side and CN side.

3. Analyzing Poor Performance of Data Transfer by DCH

The mechanism at the air interface of HSDPA is different from that of DCH, so different factors affect data transfer on DCH and HSDPA.

5.3.3 shows the flow for analyzing RAN side problem about poor performance of data transfer on DCH.

1. Flow for analyzing RAN sideproblem about poor performance of data transfer on DCH

NE Alarms

Alarm check

If the performance of data transfer for PS services is poor, analyze NodeB and RNC alarms. The clock alarms, alarms on transmission error rate, and transmission interruption may cause fluctuation of PS data. For querying NodeB and RNC alarms, see W-Equipment Room Operations Guide.

Data transfer affected by Uu interface

When PS services are carried by DCH, the factors affecting data transfer at Uu interface includes:

DCH bandwidth State transition Block error rate (BLER) at Uu interface

5.3.3 shows the flow for analyzing data transfer affected by Uu interface.

2. Flow for analyzing data transferaffected by Uu interface

DCH bandwidth When PS services are carried by DCH, the RNC assigns bandwidth for each connected UE. The bandwidth depends on spreading factor and coding method.

On RNC LMT, in the Connection Performance Measurement-Uplink Throughput and Bandwidth, Downlink Throughput and Bandwidth window, check the uplink and downlink assigned bandwidth and throughput. The bandwidth is the channel bandwidth assigned to UE by RAN. The DlThroughput is the actual downlink rate of data transfer. Assigning bandwidth (namely, code resource, power resource, and Iub resource are normal) is normal if one of the following conditions is met:

The bandwidth is the same as the request rate or subscribed rate. Maximum assignable rate (such as 384 kbps) is met upon DCH bearer.

If the bandwidth assigned to UE is smaller than the expectation, there are two causes:

Congestion or other causes. The RAN cannot assign UE with channels of higher rate, which is abnormal.

DCCC algorithm of RNC. If the DCCC algorithm parameter is rational, the decline of rate is normal.

Enable the DCCC algorithm in the existing network so that the system can save resource by reducing assigned bandwidth upon decline or pause of data transfer. However, the DCCC algorithm configuration may be irrational. DCCC algorithm involves rate adjustment based on traffic and coverage, and rate adjustment in soft handover (SHO) SHO areas. According to the parameters configured on site and based on algorithm, judge whether the assignment and adjustment of DCH bandwidth are rational, whether there are abnormalities, and whether the problem is solve by adjusting parameters. If the assigned DCH bandwidth is small due to congestion and other abnormalities, solve the problem by the following methods:

Trace signaling of single subscriber Query cell downlink load, assignment of code resource, and available

bandwidth at Iub interface Obtain CHR from BAM and check the abnormalities on RNC INSIGHT

PLUS or Nastar. BLER at Uu interface

The BLER at uplink and downlink Uu interface directly affect data transfer of PS services. If the average of UL BLER or DL BLER measured in a period is equal to or better than BLER Target, the code errors at Uu interface are normal. Otherwise, analyze this problem. DL BLER measurement: collect DT data by Probe and UE, and then import the DT data to Assistant for analysis. UL BLER measurement: In Connection Performance Measurement-Uplink Transport Channel BLER window, import the measurement file to Assistant, and analyze together with the Probe DT data files.

The power control and coverage affects the uplink and downlink BLER in the following aspects:

Outer loop power control switch. Check that the outer loop power control switch of RNC is on.

Coverage. Check whether the uplink and downlink are restricted in the areas with bad UL BLER and DL BLER. For details, see W-RF Optimization Guide.

Performance of UE. Change a UE of other types and compare their performance.

In Sequence Delivery Set the sequence submission to TURE or FALSE. This affects the rate and

fluctuation of downlink. If you set the sequence submission to TURE, the RLC keeps the transfer sequence of upper-layer PDUs. If set the sequence submission to FALSE, the receiver RLC entity allows sending SDUs to upper-layer in a sequence different from the sender. If you set the sequence submission to FALSE, the uplink rate for data transfer will be low and data transfer fluctuates much.

Setting sequence submission to TURE by executing the command MOD GPRS on Huawei HLR is recommended.

Data Transfer Affected by Iub Interface

The transport code error at Iub interface, delay jitter, and Iub bandwidth affect the performance of data transfer. 5.3.3 shows the flow for analyzing data transfer affected by Iub interface.

3. Flow for analyzing data transferaffected by Iub interface

Transport code error and delay jitter According to transport alarms and clock alarms, check whether there are problems. Bandwidth at Iub interface

Check whether the Iub interface is congested by the following methods: Querying the bandwidth at Iub interface on RNC LMT and NodeB LMT. Referring to the section Flow for Analyzing Cell-level Traffic Statistics Data. Checking abnormal record in CHR

Querying bandwidth at Iub interface at RNC side proceeds as below: Query adjacent node corresponding to each cell by executing the command LST AAL2ADJNODE Query the path of the NodeB by executing the command LST AAL2PATH. Query the bandwidth by executing the command LST ATMTRF. Query the residual bandwidth by executing the commands DSP AAL2ADJNODE and DSP

AAL2PATH at RNC side. Querying the bandwidth at Iub interface at NodeB side proceeds as below: AAL2PATH is necessary at NodeB. The relevant commands include LST AAL2PATH and DSP AAL2PATH.

Comparison of Throughput at APP and RLC Layer

The throughput at APP and RLC layer is obtainable by DT/CQT. For the theoretical relationship of rate at each layer, see the appendix 8.2. If the rate of APP throughput and RLC throughout is lower than the normal range according to theoretical analysis, the retransmission cost of TCP/IP is over large. Check and modify the TCP receiver window and MTU configuration. For the method, see the appendix 8.4 and 8.5.

4. Analyzing Poor Performance of Data Transfer by HSDPA at RAN Side

The HSDPA network schedules power and code resources by code division or time division between multiple subscribers. When there is only one HSDPA subscriber in a cell, the following factors affect the rate for data transfer:

HSDPA available power Number of HS-PDSCH codes in cell (when there is only one subscriber, a

HS-SCCH is necessary) Category of UE (maximum number of codes supported by UE and whether to

support 16QAM) Radio signals near UE

In addition, the following factors affect the reachable maximum rate:

Subscribed rate Bandwidth at Iub interface Maximum rate supported by RNC, NodeB, GGSN, and SGSN.

When there are multiple subscribers, besides previous factors, the scheduling algorithm used by NodeB and number of HS-SCCH configured to cell affects the rate of data transfer.

An HSDPA subscriber works as below:

The UE reports CQI on HS-DPCCH. The NodeB obtains the CQI of UE's location.

The scheduling module inside NodeB evaluates different subscribers by channel conditions, the amount of data in cache for each subscriber, the last serving time. It then determines the HS-DSCH parameters.

The NodeB sends HS-DSCH parameters on HS-SCCH, and after two slots it sends data on HS-DSCH.

The UE monitors HS-SCCH for information sent to it. If there is any schedule information, it starts receiving HS-DSCH data and buffers them.

According to HS-SCCH data, the UE judges whether to combine the received HS-DSCH data and data in soft buffer.

The UE demodulates the received HS-DSCH data, and send the ACK/NACK message on uplink HS-DPCCH according to CRC result.

If the NodeB receives the NACK message, it resends the data until it receives the ACK message or reaches the maximum retransmission times.

In the DT tool Probe, out of consideration for multiple subscriber scheduling and retransmission at MAC-HS layer, there are three rates at MAC-HS layer:Scheduled RateServed RateMAC Layer Rate.

Served Rate = Scheduled Rate * HS-SCCH Success Rate MAC Layer Rate = Served Rate * (1- SBLER)

Scheduled rate Schedule rate = total bits of all TBs received in statistics period/total time with TB scheduled in statistics period The total bits of all TBs received in statistics period include all the bits of received correct and wrong TBs. The total time with TB scheduled in statistics period includes the time with data received and excludes the time without data received.

Served rate Served rate = total bits of all TBs received in statistics period/statistics period The total bits of all TBs received in statistics period include the bits of received correct and wrong TBs. The statistics period includes the time with and without data received.

MAC layer rate MAC Layer Rate = total bits of correct TBs received in statistics period/statistics period The total bits of correct TBs received in statistics period include the bits of correct TBs and exclude bits of wrong TBs. The statistics period includes the time with and without data received.

HS-SCCH success rate is the success rate for receiving HS-SCCH data by UE

SLBER = wrong TBs received at MAC-HS layer/(received correct and wrong TBs)

ACK->NACK/DTX is the ratio that NodeB judges the ACK message as NACK/DTX message.

5.3.4 shows the flow for analyzing poor performance of data transfer on HSDPA at RAN side.

1. Flow for analyzingpoor performance of data transfer on HSDPA at RAN side

NE Alarms

When the performance of data transfer for PS services is poor, analyze the NodeB and RNC alarms. The clock alarms, alarms on transport code error, and transmission interruption may lead to fluctuation of PS data. For querying NodeB and RNC alarms, see W-Equipment Room Operations Guide.

Whether the Service Is Set Up on HSDPA Channel

Check the IE serving HSDSCH RL indicator of the message RB SETUP on RNC. If the IE is True, and the SF of downlink channel code is 256, the service must be carried by HSDPA channel, as shown in 5.3.4.

2. Confirming in the RNC message that PS service is set up on HSDPA channel

You can also check the information like reported CQI in the WCDMA HSDPA Link Statistics window in the DT software Probe. If no information is in the window, the service must be carried on DCH, as shown in 5.3.4.

3. Confirming in Probe that service is set up on HSDPA channel

If the service is not set up on HSDPA channel, it will automatically be set up on DCH. Now the service rate is the rate of R99 service, usually equal to or smaller than 384 kbps.

If it is confirmed that the service is not set up on HSDPA channel, analyze it from the following aspects.

HSDPA cell is not set up Check at RNC side whether the HSDPA cell is activated by executing the command LST CELLHSDPA. Check at NodeB side whether the local cell supports HSDPA. Check by executing the command LST LOCELL whether the value of the local cell is TRUE or FALSE. If the HSDPA cell at RNC side is not activated, activate it by executing the command MOD LOCELL: LOCELL=0, HSDPA=TRUE. In addition, during modifying the HSDPA cell configuration on RNC, if HSDPA codes are statically assigned, and if there are excessive R99 subscribers connected to the cell so the code assigned to HSDPA is inadequate, the RNC still displays that the modifying HSDPA cell configuration succeeds. However, actually the HSDPA cell is not successfully set up. Check whether the codes assigned to HSDPA cell are successful by selecting Realtime Performance Monitoring > Cell Performance Monitoring > Code Tree Tracing on RNC.

Incorrect type of HSDPA AAL2PATH or No Configuration Set the type of HSPDA AAL2PATH to HSDPA_RT or HSDPA_NRT. Otherwise the cell can support R99 services only, but not HSDPA services. It is recommended that one HSDPA AAL2PATH is configured to one NodeB. If multiple HSDPA AAL2PATHs are configured, the data packets are easily dropped in the current version. Query it at RNC or NodeB side by executing the command LST AAL2PATH. If the HSDPA AAL2PATH is set to RT or NRT, the downlink subscription rate of UE is 2 Mbps. When the UE accesses the network, setting subscriber plane for HSDPA service fails, and the RNC will automatically set up the subscriber plane of PS 384kbps service. According to signaling of the RB Setup message, the service is set up on R99, and SF is 8.

HSDPA subscriber's admission failure The HSDPA subscriber's admission failure leads to that the RNC reconfigures HSDPA service to be carried by PS384K channel of R99 service. If the service cannot be set up, the UE continues to access the network after lowering the rate of R99 service. If the rate of connected HSDPA subscriber is as low as 384 kbps, 128 kbps, or 64 kbps of R99 services according to test, confirm whether the service is set up on HSDPA channel and whether the admission fails. Check whether the following aspects are rational:

Uplink and downlink load of R99 services Downlink code resource Iub transmission resource Number of HSDPA subscribers Threshold of HSDPA cell rate Guaranteed rate threshold of streaming service Guaranteed power threshold Over high HSDPA threshold for downlink BE service

The HSDPA threshold for downlink BE service defines the rate judgment threshold for background or interactive services carried on HS-DSCH in PS domain. If the request rate is great than or equal to the threshold, the PS service is carried on HS-DSCH; otherwise, the PS service is carried on DCH. Set HSDPA threshold for downlink BE service by executing the command SET FRC: DlBeTraffThsOnHsdpa=D384 on RNC.

Low Scheduled Rate

The TB size of NodeB scheduling depends on CQI, HSDPA codes, available power for HSDPA, and so on. TB size/2ms is scheduled rate.

Normally, there is mapping relationship (depending on mapping table of NodeB CQI in actual use) between the schedule rate and CQI reported by UE. The NodeB will filter and adjust the CQI reported by UE, so the scheduled rate and CQI scheduled by NodeB have mapping relationship, not completely having mapping relationship with the CQI reported by UE. 5.3.4 lists the relationship between CQI and TB size according to the protocol 3GPP 25.306. It is only for reference, the product realization does not completely consist with protocol.

1. Relationship between CQI and TB size when the UE is in category 1112

CQI value

Transport Block Size

Number of HS-PDSCH

Modulation

Reference power adjustm

ent

0 N/A Out of range

1 137 1 QPSK 0

2 173 1 QPSK 0

3 233 1 QPSK 0

4 317 1 QPSK 0

5 377 1 QPSK 0

6 461 1 QPSK 0

7 650 2 QPSK 0

8 792 2 QPSK 0

CQI value


Number of HS-PDSCH

Modulation


ent

9 931 2 QPSK 0

10 1262 3 QPSK 0

11 1483 3 QPSK 0

12 1742 3 QPSK 0

13 2279 4 QPSK 0

14 2583 4 QPSK 0

15 3319 5 QPSK 0

16 3319 5 QPSK 1

17 3319 5 QPSK 2

18 3319 5 QPSK 3

19 3319 5 QPSK 4

20 3319 5 QPSK 5

21 3319 5 QPSK 6

22 3319 5 QPSK 7

23 3319 5 QPSK 8

CQI value


Number of HS-PDSCH

Modulation


ent

24 3319 5 QPSK 9

25 3319 5 QPSK 10

26 3319 5 QPSK 11

27 3319 5 QPSK 12

28 3319 5 QPSK 13

29 3319 5 QPSK 14

30 3319 5 QPSK 15

2. Relationship between CQI and TB size when the UE is at the level 16

CQI value


Number of HS-PDSCH

Modulation

Reference power adjustment

0 N/A Out of range

1 137 1 QPSK 0

CQI value


Number of HS-PDSCH

Modulation


2 173 1 QPSK 0

3 233 1 QPSK 0

4 317 1 QPSK 0

5 377 1 QPSK 0

6 461 1 QPSK 0

7 650 2 QPSK 0

8 792 2 QPSK 0

9 931 2 QPSK 0

10 1262 3 QPSK 0

11 1483 3 QPSK 0

12 1742 3 QPSK 0

13 2279 4 QPSK 0

14 2583 4 QPSK 0

15 3319 5 QPSK 0

16 3565 5 16-QAM 0

CQI value


Number of HS-PDSCH

Modulation


17 4189 5 16-QAM 0

18 4664 5 16-QAM 0

19 5287 5 16-QAM 0

20 5887 5 16-QAM 0

21 6554 5 16-QAM 0

22 7168 5 16-QAM 0

23 7168 5 16-QAM 1

24 7168 5 16-QAM 2

25 7168 5 16-QAM 3

26 7168 5 16-QAM 4

27 7168 5 16-QAM 5

28 7168 5 16-QAM 6

29 7168 5 16-QAM 7

30 7168 5 16-QAM 8

The following factors affect scheduled rate:

CQI If the downlink rate of UE is low, check whether the CQI reported by UE is over low, and check the PCPICH RSCP and Ec/Io of the serving cell from the following aspects:

The coverage is weak, and the CQI reported by UE is low. The interference is strong, and there is pilot pollution, and the CQI reported

by UE is low. When the HSDPA serving cell is frequently updated, the HSDPA subscribers

cannot change accordingly due to punishment, so the CQI reported by UE is low.

If the coverage is weak, improve the CQI reported by UE by RF optimization and constructing sites.

If the interference is strong, adjust the azimuth and down tilt in RF optimization. This forms a primary cell.

If the HSDPA serving cell is frequently updated, avoid frequent handover by adjusting antenna azimuth and down tilt or constructing sites in RF optimization.

Available power of HSDPA cell If the available power of HSDPA cell is over low, the TB size of NodeB scheduling will be affected. HSDPA power configuration includes dynamic and static configuration. The RNC MML is MOD CELLHSDPA: HSDPAPOWER=430. The unit of HSDPA power is 0.1 dB. The total power of all HS-PDSCHs and HS-SCCHs must not exceed the HSDPAPOWER. When HSDPAPOWER in previous formula is higher than or equal to total power of cell, the HSDPA power configuration is dynamic configuration. The available power of HSDPA cell = total power of cell * (1 power margin) power used by R99 TCH and CCH. When HSDPAPOWER in previous formula is lower than total power of cell, the HSDPA power configuration is static configuration. Namely, the available power of HSDPA cell is the HSDPAPOWER. However, the maximum available power = total power of cell * (1 power margin) CCH power.

In static power distribution, the R99 services may occupy the power of HSDPA cell, so the actual power used by HSDPA cell is not the configured power.

Analyze the factors affecting available power of HSDPA cell from the following aspects:

Query power margin by executing the command LST MACHSPARA on NodeB. The default power margin is 10%, namely, the total downlink load of cell can use 90% of total power of cell.

On RNC LMT, select Realtime Performance Monitoring > Cell Performance Monitoring > Tx Carrier Power. Observe the transmit carrier power and power used by non-HSDPA subscribers. The available power of HSDPA = transmit carrier power - power used by non-HSDPA subscribers. If the power used by non-HSDPA subscribers is over high, the available power of HSDPA cell becomes low, so the scheduled rate is affected.

Available codes of HSDPA cell If inadequate codes are assigned to HSDPA subscribers, the TB size of NodeB scheduling will be affected..

HSDPA UE CATEGORY The 3GPP protocol 25.306 defines 12 types of UE category. In a TTI, the UE of a type obtains different maximum TB size, so the maximum scheduled rate obtained by UE is different. The UE reports its capability in the IE hsdsch physical layer category of the RRC Connection Setup Complete message..

Amount of data to be transmitted being smaller than the maximum TB size The TB size scheduled by NodeB depends on the available power and codes of the subscriber, as well as the amount of data transferred by the subscriber. If the amount of data sent is smaller than the maximum scheduled TB size, the rate at physical layer is lower than the expectation. This problem occurs when there is data in NodeB buffer but the amount of data is inadequate for a scheduled maximum TB size.

Low Served Rate

According to the previous formula Served Rate = Scheduled Rate * HS-SCCH Success Rate, if the scheduled rate is normal, over low HS-SCCH success rate leads to over low served rate. If there is only one subscriber in normal conditions, and the HS-SCCH power and traffic are not restricted, the success rate of HS-SCCH is shall be highly approach to 100%.

The success rate of HS-SCCH is relevant to HS-SCCH power, number of HS-SCCHs, number of subscribers, scheduling algorithm, and transported traffic. The following paragraphs describe them respectively.

HS-SCCH power distribution The HS-SCCH is a downlink CCH, shared by all subscribers. The UE keeps monitoring UE ID on HS-SCCH, and judge whether the UE ID is for itself. If the UE ID is for itself, it demodulates HS-PDSCH data. Therefore, correct demodulation of HS-SCCH goes before data transfer.

There are three types of HS-SCCH power, transit SET

MACHSPARA in NodeB , 0 shows that HS-SCCH power control is based on CQI . 1 shows HS-SCCH power changeless; 2 shows use a power control mode which go with DCH and keep a fixed power deflection

value. Default is 0. (Attention: the edition before NodeB3812EV100R007C03B040 cant be set to type 0, need use type 1 .) The HS-SCCH power is in static configuration or dynamic configuration. The default configuration is static configuration. Set the HS-SCCH power to a fixed ratio of maximum transmit power of cell as below:

Set the ratio to 3% in indoor environment. Set the ratio to 5% in outdoor environment.

Set the HS-SCCH power on NodeB LMT by executing the command below: SET MACHSPARA: PWRFLG=FIXED, PWR=5; HS-SCCH power can be configured as dynamic power control, which is achieved by setting a power offset to the pilot bit of DL-ADPCH. The power offset is relevant to spreading factor of downlink DPCH and whether the UE is in SHO state. When this method is used, the HS-SCCH power offset is listed as in 5.3.4. The MML command is as below: SET MACHSPARA: PWRFLG=DYNAMIC;

1. HS-SCCH power offset

Spreading factor of downlink DPCH

HS-SCCH power offset in non-SHO period

HS-SCCH power offset in SHO period

4 10.75 6.75

8 7.75 3.75

16 4.75 0.75

32 1.75 +2.25

64 +1.25 +5.25

128 +4.25 +8.25

256 +7.25 +11.25

0 shows that HS-SCCH power control is based on CQI , which works like this: First set HS-SCCH initialization TX power Then according to CQI change , adjust HS-SCCH power, like DCH inner-loop power control. At last , according to the ACK/NACK/DTX information from HS-DPCCHs feedback ,adjust HS-SCCH power , like DCH outer-loop power control. The parameter of the power control which base on CQIs HS-SCCH : HS-SCCHs initial power , Default is 28(-3 dBm), relative to pilot power ; HS-SCCH power controls aim FER , Default is 10%(1%)

Number of HSDPA subscribers and number of HS-SCCHs The success rate of HS-SCCH is relevant to number of subscribers.

If there is only one HSDPA subscriber in a cell, the traffic is not restricted and HS-SCCH power is adequate, the success rate of HS-SCCH for the subscriber approaches 100%.

If there are multiple HSDPA subscribers in the cell, the success rate of HS-SCCH for each subscriber is relevant to scheduling algorithm and number of HS-SCCHs.

Usually set the HS-SCCH according to available power of HS-PDSCH, code resource, and traffic of service source. For example, if UEs used in the cell are all category 12 UE, set number of HS-PDSCH codes and number of HS-SCCHs as below:

If you set 5 codes to HS-PDSCH, it is recommended to set 2 HS-SCCHs. If you set 10 codes to HS-PDSCH, it is recommended to set 3 HS-SCCHs. If you set 14 codes to HS-PDSCH, it is recommended to set 4 HS-SCCHs. Scheduling algorithm

Using different scheduling algorithm for multiple subscribers enables each subscriber to be scheduled at different probability. For example,

Documents

WCDMA PS Service Optimization Guide