131168158 WCDMA UTRAN Optimization Flow PDF

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Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.

WCDMA UTRAN Optimization Flow

Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page2

Foreword

WCDMA optimization is a very important part in the

lifecycle of the network.

Mainly, the optimization includes the preparation, single

site verification, RF optimization and 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


Contents


2. The Preparation for the Optimization Project


4. RF Optimization




WCDMA Optimization Flow

Project Start

Single Site

Verificaiton

Preparation and

Startup

RF

Optimization

Parameter

Optimization

Acceptance and

Report

· Network Information

Collection

· Cluster Division and

Team Establishment

· Optimization Tools

· Preparation

· Drive Test and RNC

Configuration Collection

· Trouble shooting

· Engineering Parameter

Adjustment· Preparation

· Data Collection

· DT and Statistic

Analysis

· Parameter Adjustment


Introduction of Optimization Flow

Final Documents:

SSV Reports

Optimization Report

Engineering Parameter Table

Cell Parameter Table

Process Documents:

Engineer Parameter Table

Cell Parameter Table

Parameter Changing Record


Contents


2. The preparation for the Optimization Project


4. RF Optimization




WCDMA Optimization Flow - Preparation

Project Start

Single Site

Verificaiton

Preparation and

Startup

RF

Optimization

Parameter

Optimization

Acceptance and

Report


Collection


Team Establishment


· Preparation



· Trouble shooting



· Data Collection

· DT and Statistic

Analysis



The Preparation for Projection

The following work is required:

Understanding of the Existing Network

Cluster Division and Optimization Team Establishment

Optimization Tools and Software


The Preparation for Projection

Understanding of the Existing Network :

Radio Network Planning report

Latest engineering parameter table and cell parameter table

OMC statistic data

Subscriber complaints

Historical Optimization Reports


The Preparation for the Optimization Projection Cluster Division

One cluster should cover one continuous area, which is

convenient for one time drive test;

Cluster division should consider the terrain,

administration and main roads.


The Preparation for the Optimization Projection Optimization Team Establishment

RNO leader-1

Data Analyzer

Drive Test Operator

Driver

RNO leader-n

Data Analyzer

Drive Test Operator

Driver

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

RNO manager


The Preparation for the Optimization Projection Optimization Tools

Hardware

UMTS Scanner

UMTS Test UE

GPS and data line

Laptop

Digital camera

Spectrum analyzer

Software:

DT tools

Post processing tools

MapInfo

Google earth


Contents




4. RF Optimization




WCDMA Optimization Flow – Single Site Verification

Project Start

Single Site

Verificaiton

Preparation and

Startup

RF

Optimization

Parameter

Optimization

Acceptance and

Report


Collection


Team Establishment


· Preparation



· Trouble shooting



· Data Collection

· DT and Statistic

Analysis



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

Installation 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 - Tasks of the on-site engineers

Application key

Preparations

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

Configuration Data Collection and Check check whether the data configured is consistent with the planned

data

Testing Point Selection

Test UE Setup Set the UE to testing mode before test

Other Preparations


Single Site Verification - Tasks of the on-site engineers Verification in Idle Mode

Frequency Check

Check whether the frequency is consistent with the planned data

Scramble Check

Check whether the scramble is consistent with the planned data

LAC/RAC Check

Check whether the LAC/RAC is consistent with the planed data.

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


Single Site Verification - Tasks of the on-site engineers Verification in connected Mode

Originating and Terminating Call 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

Access Test of PS Services

Check whether the PS services access are normal

Solving Problems


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

Testing Tools

Hardware

Software


Single Site Verification – Task of the RNO engineers Coverage Check

Check whether CPICH RSCP and CPICH Ec/Io received by

scanner is normal

Inconsistency of antenna tile/direction angle from planned

one

Check whether the RX ports of different cell are reversely

connected

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

cells in OMC room

Checking Antennas by Exchanging Feeders, measure the RSCP

before and after.


Single Site Verification – Task of the RNO engineers

Service Function Test

MOC and MTC of Voice call

MOC and MTC of VP

UL and DL R99 PS service

HSDPA access function and throughput test

HSUPA access function and throughput test


Single Site Verification – Task of the RNO engineers

Solving Problems

If RNO engineers find out some installation problem, ask

the installation team fix it and do retest to verify

If RNO engineers find problems about product function,

RNO engineers must ask RAN engineers help to solve

problems



Summarization:

In single site verification stage, engineers check whether

equipment functions are normal

Single site verification is a basis for the following RF

optimization and Parameter optimization

If all verifications about function are accepted, the single

site verification is completed


Contents




4. RF Optimization




WCDMA Optimization Flow – RF Optimization

Project Start

Single Site

Verificaiton

Preparation and

Startup

RF

Optimization

Parameter

Optimization

Acceptance and

Report


Collection


Team Establishment


· Preparation



· Trouble shooting



· Data Collection

· DT and Statistic

Analysis



RF Optimization - Overview

Once all the sites on-air and verification is completed, RF

optimization starts

During the RF optimization stage, you willoptimize radio

frequency (RF) signals , so that the distribution of radio signal

is normal in next stage -- parameters optimization

RF optimization includes the following aspects:

Coverage optimization

Pilot pollution optimization

Handover optimization


RF Optimization flow


RF Optimization - Preparation (1)

Define Optimization targets

Weak coverage

Pilot pollution

SHO Factor based on DT

Define Test Route

Cluster Division

Preparing Tools and Data

Preparing Software

Preparing Hardware

Engineering and cell Parameter table



Index Reference Remarks

CPICH Ec/Io ≥ –9dB

≥ 97% in urban 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. ≥ 97% in suburban

area

CPICH RSCP ≥ –

95dBm

≥ 98% in urban 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.

≥ 95% in suburban

area

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



Dividing Clusters

RF optimization must be performed on a group of or a

cluster of NodeBs , and to ensure that interference from

intra-frequency neighbor cells are considered during

optimization.

Define Test Route

The test route should cover all sites, all main roads and VIP

area.


RF Optimization - Preparing Tools and Data:

Software

Genex Probe

Genex Assistant

Mapinfo

Google earth

Device

Scanner

Test terminal and

data line

GPS 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

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

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

The coverage problems to be analyzed include:

Weak coverage

Overshoot coverage

Unbalance between uplink and downlink

No dominating cell



Coverage Analysis Processes:

Downlink Coverage Analysis

Analyzing Pilot Strength

Analyzing Pilot quality

Analyzing Dominate Cell

Analyzing comparison of UE and Scanner Coverage

Uplink Coverage Analysis

Analyzing Uplink Interference

Analyzing distribution of UE Transmit Power



Downlink coverage analysis – Pilot Strength Analysis

Check areas of weak 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 for further analysis


RF Coverage Problem Analysis Downlink coverage analysis - Pilot Strength Analysis



Downlink coverage analysis - Pilot 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

-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 quality Analysis:



-15.5

-104

-20

-19

-18

-17

-16

-15

-14

Ec/Io RSCP

-120

-115

-110

-105

-100

-95

-90What’s the

problem?

Downlink coverage analysis - Pilot quality Analysis:



Downlink coverage analysis - Analyzing Dominating Cell:

Dominating cells analysis is analyzing cell scramble

information obtained in DT

The contents to be checked include :

Weak coverage cell

Cross-cell coverage cell

No dominating cell


RF Coverage Problem Analysis Downlink coverage analysis - Analyzing Dominating Cell:


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

Inconsistent Best Service Cell between scanner and UE



Uplink coverage analysis:

Uplink coverage analysis is analyzing UE transmit power

obtained in DT

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: UE_Tx_Power ≤ 0 dBm

Fair: 0 dBm < UE_Tx_Power ≤ 10 dBm

Poor: UE_Tx_Power > 10 dBm

Assume the optimization indexes of UE transmit power as

below:



The distribution of UE transmit power

Uplink Uplink Coverage - Distribution of UE Transmit Power

The distribution of UE transmit power reflects the distribution

of uplink interference and uplink path loss


Pilot Pollution Problem Analysis

Pilot Pollution Point Definition:

The pilot pollution is that excessive strong pilots exist in a

point but no 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



Influence of Pilot Pollution :

Pilot pollution causes the following network problems:

Ec/Io Deterioration

Call Drop Due to Handover

Capacity Decline



-62 -63

-64 -66 -67

-81

-90

-85

-80

-75

-70

-65

-60

SC1 SC2 SC3 SC4 SC5 SC6

RS

CP

(d

Bm

)

Active Set Pilot Pollution

Margin

Not

Pilot Pollution

Pilot Pollution Definition - Judgment Standards :



Pilot Pollution - Estimated Active Set Size:



SC Count % in Pollution Set

8 206 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 investigated

Pilot Pollution - Estimated Active Set Size

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 CPICH Power

Ambient Factors



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 The neighbor cell optimization includes adding and

removing neighbor cells.

Add: Missing neighbors

Remove: The neighbors are never measured but in the

neighbor list.

Neighbor cell optimization can be analyzed by :

Scanner Data

UE Data Analysis

Careful consideration is needed prior to removing neighbours


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 .



Controlling SHO Factor based on DT:

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

SHO Factor based on DT, defined as below:

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



UE SHO Performance

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

from software Number of Active Set Updates

Event Count

Event 1a - 328

Event 1b - 306

Event 1c - 64

Number of Active Set Update Completes

Event Count

Event 1a - 326

Event 1b - 305 Event 1c - 62

Soft-Handover Success Rate

Event Rate

Event 1a - 99.4

Event 1b - 99.7

Event 1c - 96.9


RF Analysis Approaches – Neighbor List

Controlling SHO Factor based on DT

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


Contents




4. RF Optimization




WCDMA Optimization Flow – Parameter Optimization

Project Start

Single Site

Verificaiton

Preparation and

Startup

RF

Optimization

Parameter

Optimization

Acceptance and

Report


Collection


Team Establishment


· Preparation



· Trouble shooting



· Data Collection

· DT and Statistic

Analysis



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 data and tools for analysis:

Drive test data and analysis tools

Statistic data and analysis tools

RNC trace and logs data

MSC & SGSN record if necessary


Drive test The contents of drive test

Idle mode test

The short call test for voice service

The continuous call test for voice service

The short call test for video phone service

The continuous call test for voice service

The access test for R99 PS service

The continuous call test for R99 PS service

HSDPA FTP download test

The test should be performed repeatedly to the position with

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 – Optimization Report Output

Project Start

Single Site

Verificaiton

Preparation and

Startup

RF

Optimization

Parameter

Optimization

Acceptance and

Report


Collection


Team Establishment


· Preparation



· Trouble shooting



· Data Collection

· DT and Statistic

Analysis



Optimization Report

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 you www.huawei.com

131168158 WCDMA UTRAN Optimization Flow PDF

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