w kpi monitoring and improvement guide ps service optimization 20081218 a 32

WCDMA PS Service Optimization Guide For Internal Use Only

Product name Confidentiality levelWCDMA RNP For internal use onlyProduct version Total 166 pages 3.2

WCDMA PS Service Optimization Guide (For internal use only)

Prepared by Yu Yongxian Date 2006-03-22Reviewed by Xie Zhibin, Chen Qi, Xu Zili, Xu

Dengyu, Jiao Anqiang, Hu Wensu, Ji Yinyu, Qin Yan, Wan Liang, and Ai Hua

Date2006-03-22

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

Huawei Technologies Co., Ltd.All Rights Reserved

2011-10-27 All rights reserved Page1 , Total166


Revision RecordsDate Version Description Reviewer Author2004-11-26 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



Date Version Description Reviewer Author2006-10-24 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 APP

layer throughput.

7 Adding the recommendation of V17 SET

HSDPATRF commands change.

8 Modify the wrong description about

TCP/IPs content.

Wang Dekai

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.

Hua Yunlong

2008-10-24 3.22 Adding UMAT tools analyze HSDPAs

throughput problem. Modifying some content

Hu Wensu, Ji Shuqi

, and Fang MingZheng Kaisi

2008-12-183.23 Change the format and covert to KPI

Monitoring and Improvemnet Guilde series.He fengming



Contents

3.1 Traffic Statistics......................................................................................................................................................193.2 DT/CQT..................................................................................................................................................................203.3 Others......................................................................................................................................................................224.1 Traffic Statistics Indexes Related to Throughput...................................................................................................254.2 Generic Analysis Flow............................................................................................................................................29

4.2.1 Flow for Analyzing RNC-level Traffic Statistics Data.....................................................................................294.2.2 Flow for Analyzing Cell-level Traffic Statistics Data......................................................................................32

5.1 Access Failure.........................................................................................................................................................395.1.1 Originating PS Service by UE Directly............................................................................................................395.1.2 UE as the Modem of PC...................................................................................................................................40

5.2 Disconnection of Service Plane.............................................................................................................................465.2.1 Analyze Problems at RAN Side........................................................................................................................465.2.2 Analyzing Problems at CN Side.......................................................................................................................51

5.3 Poor Performance of Data Transfer........................................................................................................................545.3.1 Checking Alarms..............................................................................................................................................555.3.2 Comparing Operations and Analyzing Problem...............................................................................................565.3.3 Analyzing Poor Performance of Data Transfer by DCH..................................................................................575.3.4 Analyzing Poor Performance of Data Transfer by HSDPA at RAN Side.........................................................625.3.5 Analysis of the Problem about Poor Data Transmission Performance of the HSUPA on the RAN Side.........815.3.6 Analyzing Poor Performance of Data Transfer at CN Side............................................................................115

5.4 Interruption of Data Transfer................................................................................................................................1195.4.1 Analzying DCH Interruption of Data Transfer...............................................................................................1195.4.2 Analyzing HSDPA Interruption of Data Transfer...........................................................................................121

6.1 Cases at RAN Side...............................................................................................................................................1246.1.1 Call Drop due to Subscriber Congestion (Iub Resource Restriction).............................................................1246.1.2 Uplink PS64k Service Rate Failing to Meet Acceptance Requirements in a Test (Air Interface Problem)...1246.1.3 Statistics and Analysis of Ping Time Delay in Different Service Types.........................................................1256.1.4 Low Rate of HSDPA Data Transfer due to Over Low Pilot Power................................................................1266.1.5 Unstable HSDPA Rate due to Overhigh Receiving Power of Data Card.......................................................1276.1.6 Decline of Total Throughput in Cell due to AAL2PATH Bandwidth larger than Actual Physical Bandwidth.................................................................................................................................................................................1276.1.7 Causes for an Exceptional UE Throughput and Location Method in a Field Test.........................................129

6.2 Cases at CN Side..................................................................................................................................................133



6.2.1 Low FTP Downloading Rate due to Over Small TCP Window on Server TCP............................................1336.2.2 Simultaneous Uploading and Downloading...................................................................................................1346.2.3 Decline of Downloading Rate of Multiple UEs.............................................................................................1356.2.4 Unstable PS Rate (Loss of IP Packets)...........................................................................................................1366.2.5 Unstable PS Rate of Single Thread in Commercial Deployment (Loss of IP Packets)..................................1386.2.6 Unavailable Streaming Service for a Subscriber............................................................................................1396.2.7 Unavailable PS Services due to Firewall of Laptop.......................................................................................1396.2.8 Low PS Service Rate in Presentation Occasion.............................................................................................1396.2.9 Abnormal Ending after Long-time Data Transfer by FTP..............................................................................1406.2.10 Analysis of Failure in PS Hanodver Between 3G Network and 2G Network..............................................144

8.1 Transport Channel of PS Data..............................................................................................................................1518.2 Theoretical Rates at Each Layer ..........................................................................................................................152

8.2.1 TCP/IP Layer..................................................................................................................................................1528.2.2 RLC Layer......................................................................................................................................................1528.2.3 Retransmission Overhead...............................................................................................................................1538.2.4 MAC-HS Layer..............................................................................................................................................153

8.3 Bearer Methods of PS Services............................................................................................................................1548.3.1 DCH................................................................................................................................................................1548.3.2 HSDPA...........................................................................................................................................................1548.3.3 CCH................................................................................................................................................................155

8.4 Method for Modifying TCP Receive Window.....................................................................................................1568.4.1 Tool Modification...........................................................................................................................................1568.4.2 Regedit Modification......................................................................................................................................156

8.5 Method for Modifying MTU................................................................................................................................1578.5.1 Tool Modification...........................................................................................................................................1578.5.2 Regedit Modification......................................................................................................................................158

8.6 Confirming APN and Rate in Activate PDP Context Request Message...............................................................1598.6.1 Traffic Classes:...............................................................................................................................................1598.6.2 Maximum Bit Rates and Guaranteed Bit Rates..............................................................................................1608.6.3 APN................................................................................................................................................................160

8.7 APN Effect............................................................................................................................................................1628.7.1 Major Effect....................................................................................................................................................1628.7.2 Method for Naming APN...............................................................................................................................1628.7.3 APN Configuration.........................................................................................................................................162

8.8 PS Tools................................................................................................................................................................1638.8.1 TCP Receive Window and MTU Modification Tools....................................................................................1638.8.2 Sniffer.............................................................................................................................................................1638.8.3 Common Tool to Capture Packet: Ethereal....................................................................................................1648.8.4 HSDPA Test UE..............................................................................................................................................164

8.9 Analysis of PDP Activation..................................................................................................................................165


For Internal Use Only

Figures

Flow for analyzing RNC-level traffic statistics data...........................30Flow for analyzing cell-level traffic statistics data............................32Flow for analyzing DT/CQT data......................................................38Flow for analyzing access failure problems when originating PS services by UE directly...................................................................39Flow for analyzing access problem when the UE serves as the modem of PC.............................................................................................40Flow for processing problem of failure in opening port.....................41Flow for analyzing access failure problems .....................................42Signaling flow of successful setup of a PS service in Probe...............43Flow for analyzing disconnection of service plane............................46Flow for analyzing RAN side problem about disconnection of service plane for DCH bearer......................................................................47Connection Performance Measurement-Downlink Throughput and Bandwidth window.........................................................................48HSDPA parameters in Probe............................................................50Flow for analyzing problems at CN side about disconnection of service plane............................................................................................52Flow for analyzing poor performance of data transfer......................55Flow for analyzing RAN side problem about poor performance of data transfer on DCH.............................................................................58Flow for analyzing data transfer affected by Uu interface.................59Flow for analyzing data transfer affected by Iub interface................61Flow for analyzing poor performance of data transfer on HSDPA at RAN side .......................................................................................64Confirming 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...........65High code error of ACK->NACK/DTX in Probe ...................................76Uplink and downlink RL imbalance in handover areas.......................77Residual BLER at MAC layer in WCDMA HSDPA Decoding Statistics window.........................................................................................80Working process of an HSUPA UE....................................................82Optimization flow of a low throughput of the HSUPA UE...................85Confirming the service is set up on the HSUPA according to a signaling message of the RNC.......................................................................86How to confirm the service is set up on the HSUPA through the drive test tool Probe...............................................................................87RRC CONNECTION REQUEST message..............................................90RRC CONNECT SETUP CMP message................................................91RL RECFG PREPARE message..........................................................92Display of the Assistant HSUPA related information (limited transmit power of the UE)............................................................................93Display of the Assistant HSUPA related information (limited traffic)..94PHYSICAL SHARED CHANNEL RECONFIGURATION REQUEST message (containing the target RTWP and the background)...........................96ATM transmission efficiency...........................................................97P bandwidth utilization..................................................................98RAB assignment request message (containing an MBR)....................99RL RECFG PREPARE message (containing NodeB MBR)....................100RB SETUP message (containing the maximum number of available channel codes).............................................................................101RLC PDU retransmission rate on the Probe....................................109Receiver's CPU performance observation window...........................113Flow for analyzing poor performance of data transfer at CN side... .116Flow for analyzing interruption of data transfer.............................120Interruption delay of TCP displayed in Ethereal..............................122Variation of total throughput of one IMA link of HSDPA codes.........128Variation of total throughput of two IMA links of HSDPA codes........128Unstable PS rate (1).....................................................................137



Unstable PS rate (2).....................................................................137Analyzing packets captured by Ethereal upon unstable PS rate.......138Interactive interface in CuteFTP....................................................141Signaling of normal downloading by FTP.......................................142Signaling of abnormal downloading by FTP....................................143Signaling of normal handover between 3G network and 2G network...................................................................................................145Normal signaling flow between UE and 2G SGSN............................146Signaling flow traced on 2G SGSN.................................................147Transport channel of PS data........................................................151Packet Service Data Flow..............................................................152Running interface of DRTCP..........................................................157Detailed resolution of Activate PDP Context Request message.......159Converting ASCII codes into a character string by using the UltraEdit...................................................................................................161PDP context activation process originated by MS...........................165



Tables

Requirements by DT/CQT on PS throughput.....................................15Major parameters to be collected in DT/CQT....................................20Tools for collecting data.................................................................22Measured items related to PS throughput in overall performance measurement of RNC.....................................................................25Measured items related to PS throughput in cell performance measurement................................................................................26Measured items related to HSDPA throughput (cell measurement)....27 related to HSUPA throughput (cell measurement)...........................27Other measured items related to throughput...................................28Indexes to judge whether a cell has PS service request....................33Cell measurement/cell algorithm measurement analysis...................33Analysis of cell performance/Iub interface measurement..................34Cell Measurement/Cell RLC Measurement Analysis...........................35Comparing operations and analyzing problem.................................56Relationship between CQI and TB size when the UE is in category 1112.................................................................................................67Relationship between CQI and TB size when the UE is at the level 16.....................................................................................................68HS-SCCH power offset....................................................................71Categories of UE HSUPA capability levels.........................................89PO for the E-AGCH when the Ec/Io at the edge of cells is 12 dB......103PO for the E-RGCH when the Ec/Io at the edge of cells is 12 dB......104PO for the E-HICH when the Ec/Io at the edge of cells is 12 dB.......107Delay test result of ping packet....................................................125



WCDMA PS Service Optimization GuideKey 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 IntroductionAbout 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 performanceIt 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.

Table 1.1 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 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.


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 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 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 CollectionAbout 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.



3.1 Traffic StatisticsFor collecting traffic statistics data, see W-Equipment Room Operations Guide.



3.2 DT/CQTTo 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.

Table 1.1 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 application layer, RLC layer throughput

Probe + UE Analyze problems and 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



Parameter Tool Effect

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.



3.3 OthersAfter 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.

Table 1.1 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 data on RNC

See W-Test Guide.

Connection performance measurement, cell performance measurement, signaling tracing by RNC

RNC LMT Assistant or RNC LMT

See the online help of RNC LMT

Alarm M2000 or RNC LMT

M2000 or RNC LMT

Check alarms whether there are abnormal NEs



Data Tools for collecting data

Tools for viewing/ analyzing data

Effect Remark

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

Assistant tool for PS service test

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.



4.1 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.

Table 1.1 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 measurement

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

Serve as reference for understanding traffic model of subscribers

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.

Table 1.2 Measured items related to PS throughput in cell performance measurement


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 various services, throughput t measurement

Average throughput and volume of various service

Obtain the average throughput 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).

Table 1.3 Measured items related to HSDPA throughput (cell measurement)


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

Table 1.4 related to HSUPA throughput (cell measurement)

Measured item Major indexes EffectCell measurement/HSDPA service measurement

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.

Table 1.5 Other measured items related to throughput


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 measurementNumber 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 measurement Average receiving and sending rate of 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



4.2 Generic Analysis FlowAccording 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.

4.2.1 Flow for Analyzing RNC-level Traffic Statistics Data

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



Figure 1.1 Flow for analyzing RNC-level traffic statistics 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.



4.2.2 Flow for Analyzing Cell-level Traffic Statistics Data

Figure 1.1 Flow for analyzing cell-level traffic statistics 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.

Table 1.1 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.ConvVS.RAB.AttEstabPS.StrVS.RAB.AttEstabPS.InterVS.RAB.AttEstabPS.Bkg

Cell measurement/HSDPA service measurement

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.

Table 1.2 Cell measurement/cell algorithm measurement analysis

Index Meaning Analysis Solution

VS.LCC.BasicCongNumULVS.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.OverCongNumULVS.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.UEVS.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 of cell

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

Check alarms and CHR for causes of system abnormalities

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

Table 1.3 Analysis of cell performance/Iub interface measurement


VS.IUB.AttRLSetupVS.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 < AttRLSetup, the RL setup must have failed at lub interface. Analyze the problem for detailed causes.

VS.IUB.FailRLSetup.CfgUnsupVS.IUB.FailRLSetup.CongVS.IUB.FailRLSetup.HWVS.IUB.FailRLSetup.OM

Number of RLs failed at lub interface due to different causes in cell

Analyze the setup failure due to different causes. If the VS.IUB.FailRLSetup.Cong is large than 0, the lub interface is probably congested.

VS.DL.RL.Timing.Adjust.SuccVS.DL.RL.Timing.Adjust.Fail

Number of downlink RLs of successful and failed RLs of timing adjustment in cell

If they are larger than 0, timing adjustment is present in cell. If timing adjustment fails, the normal sending and receiving may be affected.

3) Cell Measurement/Traffic Measurement Analysis



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

Table 1.4 Cell Measurement/Cell RLC Measurement Analysis


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 DataAbout 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.

Figure 1.1 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.



5.1 Access FailureThere 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.

5.1.1 Originating PS Service by UE Directly5.1.1 shows the flow for analyzing access failure problems when originating PS services by UE directly.

Figure 1.2 Flow for analyzing access failure problems when originating 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 + UEIf 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.

5.1.2 UE as the Modem of PC5.1.2 shows the flow for analyzing access problem when the UE serves as the modem of PC.

Figure 1.1 Flow for analyzing access problem when the UE serves as the modem of PC

Failure in Opening Port5.1.2 shows the flow for processing problem of failure in opening port.



Figure 1.2 Flow for processing problem of failure in opening port

The major causes to failure in opening port include:

Port in Hard Config of Probe is incorrectly configuredCheck 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 abnormalThe 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 deactivatedThe 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 faultyRestart UE to solve the problem.



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

Successful Activation of Port but Access FailureOpening port succeeds, but access fails. This is probably due to signaling flow problem.

5.1.2 shows the flow for analyzing access failure problems

Figure 1.3 Flow for analyzing access failure problems

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.

Figure 1.4 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 failureDescription: 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 abnormalDescription: 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 rejectedDescription: 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 sideIf 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 problemIf 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.

OthersSee 5.3.2. Shrink the scope of the problem by changing each device.



5.2 Disconnection of Service Plane5.2 shows the flow for analyzing disconnection of service plane, though the PS service setup succeeds.

Figure 1.1 Flow for analyzing disconnection of service plane

5.2.1 Analyze Problems at RAN SideThe 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 bearer5.2.1 shows the flow for analyzing RAN side problem about disconnection of service plane for DCH bearer.

Figure 1.2 Flow for analyzing RAN side problem 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.

Figure 1.3 Connection Performance Measurement-Downlink Throughput and Bandwidth window

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 BearerThe 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 rateThe 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.



Figure 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 parameterIf 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-AverageWherein, 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.

5.2.2 Analyzing Problems at CN SideThe 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.

Figure 1.1 Flow for analyzing problems at CN side about disconnection of service plane

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

LANUse 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 CNIf 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.

NOTE

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.



5.3 Poor Performance of Data TransferThe 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.



Figure 1.1 Flow for analyzing poor performance of data transfer

5.3.1 Checking AlarmsIf 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.



5.3.2 Comparing Operations and Analyzing ProblemCompare 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.

Table 1.1 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.



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


The problem at RAN side.



Order

Operation Result Analysis

server, such as GPRS network


The problem cannot be located.

7 Test on other NodeBs Data transfer problem has been solved

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


The problem cannot 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.

5.3.3 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.



Figure 1.1 Flow for analyzing RAN side problem about poor performance of data transfer on DCH

NE AlarmsAlarm 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 interface5.3.3 shows the flow for analyzing data transfer affected by Uu interface.

Figure 1.2 Flow for analyzing data transfer affected by Uu interface

DCH bandwidthWhen 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.

Figure 1.3 Flow for analyzing data transfer affected by Iub interface

Transport code error and delay jitterAccording 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



NOTE

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.

5.3.4 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 RateMAC Layer Rate = Served Rate * (1- SBLER)

Scheduled rateSchedule rate = total bits of all TBs received in statistics period/total time with TB scheduled in statistics periodThe 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 rateServed rate = total bits of all TBs received in statistics period/statistics periodThe 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 rateMAC Layer Rate = total bits of correct TBs received

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