WCDMA UTRAN Optimization Flow

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Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.

WCDMA UTRAN Optimization Flow


Foreword

WCDMA optimization is a very important part in the life of the

network.

Mainly, the optimization contents the preparation, single site

verification, RF optimization, parameters optimization.


Contents

1. Introduction of Optimization Flow

2. The preparation for the Optimization Project

3. Single Site Verification

4. RF Optimization

5. Parameters Optimization

6. Optimization Report


WCDMA Optimization Flow


Introduction of Optimization Flow

Customized Document:

Acceptance Report

Optimization Report

Site Configuration Parameter Table

Radio Part Parameter configuration Table

Process Document and Data:

Site configuration Parameter Table

Radio part Parameter configuration Table

Output document:


Contents




4. RF Optimization




WCDMA Optimization Flow - Preparation


The Preparation for Projection

The following work is required:

Understanding of the Existing Network

Cluster Division and Optimization Team Establishment

Optimization Tools and Software



Understanding of the Existing Network :

Radio Network Planning report

Latest site configuration parameter table and radio part parameter

configuration table

OMC statistic data and subscriber complaints of the existing

network


The Preparation for the Optimization Projection

Cluster Division and Optimization Team Establishment

RNO leader-1

Data Analyzer

Drive Test Operator

Driver

RNO leader-n

Data Analyzer

Drive Test Operator

Driver

..................

RNO manager



Optimization Tool:

UMTS Scanner

UMTS Test UE

GPS and data line

Digital camera

spectrum analyzer

Optimization Software:

Post processing tool

MapInfo


Contents




4. RF Optimization




WCDMA Optimization Flow – Single Site Verification


Single Site Verification

Purpose:

The single site verification test is a part of the WCDMA network

optimization to ensure that the basic functions of the cell are normal, such

as call access, call quality, handover and so on.

Single site verification involves the following aspects:

Parameter setting check in idle mode

Services call (AMR/VP/PS) function check in connected mode

HSDPA function check

CPICH RSCP & Ec/Io

Installing problems check



Single site verification includes :

preparations before test

single site test

solving problems

The single site verification is completed by:

On-site engineers

RNO engineers


Single Site Verification - Task of the on-site engineers

Preparations

Site Status Check

For each cell to be measured, check Status by LMT or M2000 Status

Configuration Data Collection and Check

check whether the data configured is consistent with the planned data

Testing Point Selection

Test UE Setup

Set the handset to testing mode before test

Application key



Verification in Idle Mode

Frequency Check

Check whether the frequency number of the cell to be measured is consistent with

the planned data

Scramble Check

Check whether the scramble configuration is consistent with the planned

configuration

LAC/RAC Check

Check whether the LAC/RAC of the cell to be measured is consistent with the

planed one.

CPICH_RSCP/CPICH_Ec/Io (Near Site) Test

Check whether the CPICH RSCP and CPICH Ec/Io received by UE are greater than

the threshold



Verification in connect Mode

Originating and Terminating Connection Test of Voice Service

Check whether the originating and terminating function of voice service function normally by call quality test

Originating and Terminating Connection Test of VP Service

Check whether the originating and terminating function of VP service function normally by call quality test

Connection Test of PS Services

Check whether the originating function of PS services are normal by handset online service

Solving Problems

If on-site engineers find product function problems or parameter configuration problems, the engineers must location them and retest until the problems are solved and process terminates.


Single Site Verification – Task of the RNO engineers

Preparations

Cell Status Confirmation

Before checking site, you need to inquiry product support

engineers whether the cell is in normal status

Testing Route Selection

Before test, you must select a proper testing route according to

site distribution and local environment

Precautions



Coverage DT Check

Check whether CPICH RSCP and CPICH Ec/Io received by scanner is

normal

Abnormal power amplifier

Abnormal connection of antenna-feeder

Inconsistency of antenna tile/direction angle from planned one

Blocking by buildings



HSDPA Access Function Test

To test HSDPA access function

Check whether the antenna for receiving diversity signals is

reversely connected

Fixed Maximum Transmit Power of UE, measure the RTWP of the

cells

Checking Antennas by Exchanging Feeders



Antenna Diversity Check

The method for UE to transmit signals at the fixed maximum

power is a recommended method of test and operation

Solving Problems

If RNO engineers find problems about product function, RNO

engineers must ask product support engineers to solve problems



Summarization:

In single site verification stage, engineers check whether

equipment functions normally

Single site verification is a basis for the following RF optimization

and service optimization

If all verifications about function are accepted, the single site

verification is completed

After single site verification, optimization comes to RF

optimization


Contents




4. RF Optimization




WCDMA Optimization Flow – RF Optimization


RF Optimization - Overview

Once all the sites are installed and verification is complete, RF

optimization starts.

During the RF optimization stage, you will optimize radio frequency

(RF) signals , so that the distribution of radio signals is normal in next

service -- parameters optimization stage

RF optimization includes the following aspects:

Coverage optimization

Pilot pollution optimization

Handover optimization


RF Optimization flow


RF Optimization - Preparation (1)

Deciding Optimization target

Weak coverage

Pilot pollution

High SHO Factor based on DT

Dividing Clusters

Deciding Test Route

Confirm the KPI DT acceptance route with the operator before DT

Preparing Tools and Data

Preparing Software

Preparing Hardware

Preparing Data


RF Optimization - Preparation (2)Index Reference Remarks

≥ 97% in urban area

CPICH Ec/Io ≥ –9dB≥ 97% in suburban area

According to test result from the scanner, in unloaded and outdoor conditions, in planning coverage areas, test in a grid-like route to cover all cells.

≥ 98% in urban area

CPICH RSCP ≥ –95dBm ≥ 95% in suburban

area

According to test result from the scanner, in unloaded and outdoor conditions, in planning coverage areas, test in a grid-like route to cover all cells. The coverage level request is basic. If operators have penetration loss request, add the penetration loss to the coverage level.

SHO Factor based on DT 30%–40%

The SHO Factor based on DT should be 5% to 10% lower than the goal, because the following optimizations cause the soft handover factor to increase

Pilot pollution ratio ≤ 5% –

RF Optimization - Targets


RF Optimization - Preparation (3)

Dividing Clusters

RF optimization must be performed on a group of or a cluster of

NodeBs ,This ensures that interference from intra-frequency

neighbor cells are considered during optimization.

Dividing clusters involves approval by the operator.

Deciding Test Route

The KPI DT acceptance route is the core route of RF optimization

test routes. Its optimization is the core of RF optimization.


RF Optimization - Preparing Tools and Data:

Software

Genex Probe

Genex Assistant

Genex Nastar

Mapinfo

Device

Scanner

Test terminal and data line

Laptop

Vehicle mounted inverter

Needed data

List of engineering parameters

Map

KPI requirements

Network configuration parameters

Survey report

Single site verification checklist

Floor plan of the target buildings


RF Optimization - Data Collection

During RF optimization stage, the key is the optimization of radio

signals distribution, with the major means of DT and indoor test

DT is a major test. Collect scanner and UE data of radio signals by DT

test

Usually the DT and indoor test during RF optimization stage is based

on VP service.

During RF optimization stage, collect neighbor cell data of network

optimization and other data configured in RNC database


RF Optimization - RF problem solutions

Antenna tilt

Antenna azimuth

Antenna location

Split sector

Remove sector

Combine sector

Antenna height

Antenna type

TMA

RRU

Site location

New site


RF Optimization

Attention:

During the RF optimization ,sometimes the problems can be

resolved completely by proper adjustment, but there is also some

disadvantages of the RF optimization

The duration of the RF Optimization will be always very long

Some adjustment is difficult to implement

If the problems are not resolved by the RF optimization, it is

difficult to recover the antennas back to the former conditions

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幻灯片 34

h1 考虑删除hw, 2006-12-2


RF Optimization

Some advices:

Before the RF adjusting, we’d better survey the relative sites, and

give some applicable advice

If possible, do the RF adjustment and test the effect at the same

time


RF Coverage Problem Analysis

Coverage problem analysis is key to RF optimization. It involves

signal distribution. The coverage problems to be analyzed

include:

Weak coverage

Overshoot coverage

Unbalance between uplink and downlink

No primary pilot cell



Coverage Analysis Processes:

Downlink Coverage Analysis

Analyzing Pilot Coverage Strength

Analyzing Pilot Coverage quality

Analyzing Primary Pilot Cell

Analyzing comparison of UE and Scanner Coverage

Uplink Coverage Analysis

Analyzing Uplink Interference

Analyzing distribution of UE Transmit Power



Downlink coverage analysis - Pilot Coverage Strength Analysis

Check areas of poor coverage, suggestion value as below:

Good: RSCP ≥ -85 dBm

Fair: -95 dBm ≤ RSCP < -85 dBm

Poor: RSCP < -95 dBm

Mark the areas with weak coverage or common seamless

coverage of large areas for further analysis


RF Coverage Problem AnalysisDownlink coverage analysis - Pilot Coverage Strength Analysis



Downlink coverage analysis - Pilot Coverage quality Analysis

Ec/Io plot should also be analysed based on the thresholds :

Good: Ec/Io ≥ -8 dB

Fair: -14 dB ≤ Ec/Io < -8 dB

Poor: Ec/Io < - 14 dB

Areas of poor Ec/Io should be highlighted for further investigation



-15.5

-104

-20

-19

-18

-17

-16

-15

-14

Ec/Io RSCP-120

-115

-110

-105

-100

-95

-90 What’s the problem?

Downlink coverage analysis - Pilot Coverage quality Analysis:



-15.5

-63

-20

-19

-18

-17

-16

-15

-14

Ec/Io RSCP-90

-85

-80

-75

-70

-65

-60

What’s the problem?

Downlink coverage analysis - Pilot Coverage quality Analysis:


RF Coverage Problem AnalysisDownlink coverage analysis - Analyzing Primary Pilot Cell:



Downlink coverage analysis - Analyzing Primary Pilot Cell:

Cell primary pilot analysis is analyzing cell scramble information

obtained in DT

The content to be checked include :

Weak coverage cell

Cross-cell coverage cell

No primary pilot cell


RF Coverage Problem AnalysisDownlink coverage analysis - Analyzing Primary Pilot Cell:


RF Coverage Problem AnalysisDownlink coverage analysis - Analyzing comparison of UE and Scanner Coverage :

Inconsistent Best Service Cell between scanner and UE


RF Coverage Problem AnalysisCoverage Problem Analysis

Uplink coverage analysis is analyzing UE transmit power obtained in DT.

The quality standards of UE transmit power must be combined with optimization standards.

Assume the optimization indexes of UE transmit power as below:

UE_Tx_Power≤ 10 dBm >= 95%The test result of voice service by test

handset. Assume the maximum transmit power of UE is 21 dBm

The defined corresponding quality standards are:

Good if UE_Tx_Power ≤ 0 dBm

Fair if 0 dBm < UE_Tx_Power ≤ 10 dBm

Poor if UE_Tx_Power > 10 dBm

Uplink coverage analysis:


RF Coverage Problem AnalysisCoverage Problem AnalysisUplink - Distribution of UE Transmit Power:

The distribution of UE transmit power reflects the distribution of uplink interference and uplink path loss

The distribution of UE transmit power


Pilot Pollution Problem Analysis

Pilot Pollution Point Definition:

The pilot pollution is that excessive strong pilots exist in a point

but no primary pilot is strong enough

Pilot pollution exists if all the following conditions are met:

The number of pilots that meet the following condition is more than 4

and CPICH_RSCP > -100dBm

(CPICH_RSCP1st - CPICH_RSCP 4th)< 5dB


Pilot Pollution Problem AnalysisPilot Pollution Problem Analysis

-62 -63 -64 -66 -67

-81

-90

-85

-80

-75

-70

-65

-60

SC1 SC2 SC3 SC4 SC5 SC6

RS

CP

(dB

m)

Active Set Pilot Pollution

Margin

NotPilot Pollution

Pilot Pollution Definition - Judgment Standards :


Pilot Pollution Problem AnalysisPilot Pollution Problem AnalysisPilot Pollution Definition - Estimated Active Set Size Example Estimated Active Set Size Example :


Pilot Pollution Problem AnalysisPilot Pollution Problem Analysis

S C C o u n t % in P o llu tio n S et8 206 12.9%9 165 10.3%

10 157 9.8%11 156 9.7%12 148 9.2%13 135 8.4%16 95 5.9%17 94 5.9%18 76 4.7%19 74 4.6%20 73 4.6%21 56 3.5%32 54 3.4%35 39 2.4%37 33 2.1%43 19 1.2%48 8 0.5%53 7 0.4%67 3 0.2%80 2 0.1%

130 2 0.1%

Should be investigatedShould be investigated

Pilot Pollution Definition - Estimated Active Set Size Example :

Pilot pollution results



Causes of Pilot Pollution :

Improper Cell Distribution

Over High NodeB or Highly-mounted Antenna

Improper Antenna Azimuth

Improper Antenna Down Tilt

Improper PICH Power

Ambient Factors



Influence of Pilot Pollution :

Pilot pollution causes the following network problems:

Ec/Io Deterioration

Call Drop Due to Handover

Capacity Decline



Process for Analyzing Pilot Pollution

Analyze scanner-based RSCP for 1st Best Service Cell and Ec/Io for

1st Best Service Cell

Analyze scanner-based Whole PP

Locate the cells that cause pilot pollution of the key areas.

Judge whether the pilot pollution is caused by existence of

multiple strong pilots or lack of a strong pilot

Confirm the cells that need eliminating the coverage of an area

and that need enhancing the coverage of an area

Retest after adjustment



Solutions of Pilot Pollution :

Antenna Adjustment

PCPICH Power Adjustment

Using RRU or Micro Cells


Handover Problem Analysis

By adjusting RF parameters ,we can Control the size and location of

handover areas ,then we can eliminate handover call drop due to

sharp fluctuation and increase handover success rate.

During RF optimization stage, the involved handover problem include:

Neighbor cell optimization

Controlling SHO Factor based on DT


Handover Problem Analysis -Neighbor cell optimization

During RF optimization stage, missing neighbor cell is a key problem. The neighbor cell optimization includes adding and removing neighbor cells

Add: Missing neighbors

Remove: These neighbors that were not measured but are in the neighbor list.

Careful consideration is needed prior to removing neighbours

Neighbor cell optimization can be analyzed by :

Scanner Data

UE Data Analysis


Handover Problem Analysis - Neighbor cell optimization

By the scanner data, the Assistant can generate a neighbor cell

analysis report in the format of Excel


Handover Problem Analysis - Neighbor cell optimization

We can also analyze a missing neighbor cell by UE DT data

The daemon analysis tool can seldom analyze UE data

automatically and generate missing neighbor cells

but we can Compare the active set Ec/Io distribution diagram

measured by UE and that measured by scanner

The spots with missing neighbor cells has a poor Ec/Io

measured by UE and a strong Ec/Io scanned by scanner .


Handover Problem Analysis

According to the DT data from scanner, you can obtain the

SHO Factor based on DT, defined as below:

Controlling SHO Factor based on DT:

DTin points collected-scanner totalofNumber conditionshandover meet the that DTin points collected-scanner ofNumber

＝RatioHandoverSoft

The SHO Factor based on DT during RF optimization stage

must be 5%–10% lower than the KPI target value


Handover Problem AnalysisUE SHO Performance

The success rates for event 1a, 1b & 1c and can be obtained from

softwareNumber of Active Set UpdatesNumber of Active Set Updates

Event CountEvent 1a - 328Event 1b - 306Event 1c - 64

Number of Active Set Update CompletesNumber of Active Set Update Completes

Event CountEvent 1a - 326Event 1b - 305Event 1c - 62

Soft-Handover Success RateSoft-Handover Success Rate

Event RateEvent 1a - 99.4Event 1b - 99.7Event 1c - 96.9


RF Analysis Approaches – Neighbor List

If the SHO Factor based on DT is over large, decrease or change

the handover areas by using the following methods for

shrinking coverage areas:

Increase the down tilt

Adjust azimuth

Decrease the antenna height

Decrease the PICH power

Controlling SHO Factor based on DT:


Contents




4. RF Optimization




WCDMA Optimization Flow – ParameterOptimization


Purpose of Parameters Optimization

Purpose of parameters optimization

Decrease the access success ratio

Decrease the call drop ratio

Increase the quality of service

The tools and data for analysis:

scanner and UE

RNC record data

Statistic tools and KPI

MSC & SGSN record if necessary


Drive testThe contents of drive test

The call setup test for voice service

The continuous call test for voice service

Idle mode test

The call setup test for video phone service

The continuous call test for voice service

The call setup test for PS service

The continuous call test for PS service

The test should be performed repeatedly to the position with The test should be performed repeatedly to the position with problems to make sure that the problem is repeatable problems to make sure that the problem is repeatable


Drive Test Data Analysis

Drive Test Data Analysis

Analyzing and finding out the solution for access failure

Analyzing and finding out the solution for drop call

Analyzing and finding out the solution for service quality related

problems


Adjustment Recommendation and Implementation

Adjustment Recommendation and Implementation

Common Control Channel Power Allocation parameters

RL Maximum Power parameters

Intra-frequency Handover parameters

Inter-frequency Handover parameters

Inter-RAT Handover parameters

Power Control parameters

Access parameters

Other related parameters


Test for Special Areas

Special area refers to a small district or indoors environment

Operator offices, residence of VIP

Key hotels or entertainment location

Government location

Locations of large company or group subscribers

Locations tend to be cared , such as railway station or airport


Contents




4. RF Optimization




WCDMA Optimization Flow – OptimizationReport Output


Optimization Report

The 《optimization report》 should be presented after the project passes the

customer acceptance. The optimization report should include:

Project background introduction

Existing network status

Acceptance criteria

Optimization process

Problem analysis and adjustment recommendation, and the effect for the

implemented part

Acceptance test and result

Leftover problems and suggestions from the optimization point of view.

Thank youwww.huawei.com

WCDMA UTRAN Optimization Flow

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