gbo_011_e1_1 network quality evaluation zte university gsm-bss d&t team

GBO_011_E1_1 Network quality evaluation

ZTE University

GSM-BSS D&T Team

Objectives

At the end of this course, you will be able to:

State the concept and content of network

evaluation

Grasp test methods of DT and CQT

Grasp evaluation test result analysis

Contents

Network evaluation overview

Network evaluation test

Test result and analysis

Concepts of network evaluation

Simulate subscribers calling process.

Choose representative test samples

Test on Um interface

Test methods :DT and CQT


Network quality is the chief factor to win the competition.

Why network test evaluation?

Discover network problems,

GSM network evaluation include:

MSC statistic analysis

Radio network evaluation analysis


Probably problems in radio network

Limited frequency resource

Unreasonable engineering parameters

Unreasonable radio parameters

Unreasonable site location

Unfavorable coverage in important area and scenery spots

Weak indoor coverage in big buildings

Voice quality problems such as cacophony, intermittence,

etc.


Significance of network evaluation

Get to know the status of our own network and other

operator’s network comprehensively

Discover network problems

Propose optimization suggestions

Build high quality and stable network


Contents




Network evaluation flow

Begin

Project establish

DT preparation

CQT preparation

Performance parameter output and

analysisDT data analysis and processing

CQT data analysis and processing

Network integrated evaluation

Propose evaluation report and

communication

End



Main contents of test

Select test route and venue

Test items

Cell coverage range

co-channel and adjacent channel interference

TCH inspection

Inter cell handover

layer 3 signaling trace

customer complaints

Confirm test time, personnel and schedule


Test schedule

TIME TEST SCHEDULE

　 WEEK1 WEEK2

Mission MON TUE WED THR FRI SAT SUN MON TUE WED THR FRI

Prepare documents 　　　　　　　　　　　　

Driving Test 　　　　　　　　　　　　

CQT 　　　　　　　　　　　　

Test analysis 　　　　　　　　　　　　

KPI collection 　　　　　　　　　　　　

KPI analysis 　　　　　　　　　　　　

Evaluation report 　　　　　　　　　　　　

Summary 　　　　　　　　　　　　

Test and evaluation methods

DT （ DRIVE TEST ）

CQT （ CALL QUALITY TEST ）



key points in DT

Prepare documents for DT

Prepare DT instruments

Select representative test route

Choose proper test time (generally busy hour)

Reasonable test method

Offer abundant test analysis report

Digital map (MAPINFO, etc.)


Main documents for DT

区域基站名小区号经度（度）纬度（度）站型配置 (M)天线高度 (M)海拔高度 ( )天线方向角度度 DOWNTI LE ( )角度 (W)发射功率 BCCH载频号和平区西塔 G24041 123. 404530 41. 801780 Es8/ 8/ 8 49 102 0 10 20 62和平区西塔 G24042 123. 404530 41. 801780 Es8/ 8/ 8 49 102 120 10 13 74和平区西塔 G24043 123. 404530 41. 801780 Es8/ 8/ 8 49 102 240 10 13 26和平区军区文化站 G241121 123. 422220 41. 793950 Es6/ 6/ 6 26 79 0 0 20 26和平区军区文化站 G241122 123. 422220 41. 793950 Es6/ 6/ 6 26 79 120 0 20 24和平区军区文化站 G241123 123. 422220 41. 793950 Es6/ 6/ 6 26 79 240 5 20 78和平区省管局 G241491 123. 414440 41. 801360 Es4/ 4/ 4 26 79 0 5 20 82和平区省管局 G241492 123. 414440 41. 801360 Es4/ 4/ 4 26 79 120 5 20 74和平区省管局 G241493 123. 414440 41. 801360 Es4/ 4/ 4 26 79 240 5 20 86和平区新北站 G24181 123. 425861 41. 812807 Es6/ 6/ 4 43 96 0 10 20 76和平区新北站 G24182 123. 425861 41. 812807 Es6/ 6/ 4 43 96 120 10 20 70和平区新北站 G24183 123. 425861 41. 812807 Es6/ 6/ 4 43 96 240 10 20 92和平区建材经销 G243411 123. 409240 41. 805730 ES6/ 6/ 6 13 63 20 5 20 66和平区建材经销 G243412 123. 409240 41. 805730 ES6/ 6/ 6 13 63 140 5 20 24和平区建材经销 G243413 123. 409240 41. 805730 ES6/ 6/ 6 13 63 250 5 13 76和平区中山商行 G245351 12. 422550 41. 797420 Es6/ 6/ 6 12 45 0 0 20 24和平区中山商行 G245352 12. 422550 41. 797420 Es6/ 6/ 6 12 45 120 0 20 94和平区中山商行 G245353 12. 422550 41. 797420 Es6/ 6/ 6 12 45 240 0 20 90和平区专网局 G24641 123. 418058 41. 797785 Es8/ 8/ 8 32 85 0 0 20 62和平区专网局 G24642 123. 418058 41. 797785 Es8/ 8/ 8 32 85 120 5 20 64和平区专网局 G24643 123. 418058 41. 797785 Es8/ 8/ 8 32 85 240 5 20 82



Site and cell data

Site name, frequency, antenna data, neighbor cell, longitude,

latitude …

0. 005000. 00

10000. 0015000. 0020000. 0025000. 0030000. 0035000. 0040000. 0045000. 0050000. 00

0:00

汇总

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900M ERL（） 1800M ERL（）合计



Traffic data in 24 hours



GPS, Test handset, DT software, SIM card, vehicle, power,

laptop …


DT route selection

Highway from airport to downtown

Traffic trunks in the city

Other sections with lots of customer complaints

High traffic area, roads around important areas


DT time selection

DT shall be carried out on busy hours according to traffic

statistics, such as:

AM 9:00-12:00

PM 16:00-18:00


Test method of DT

Vehicle speed:

Downtown area: 30km/h

Common urban: 40km/h

Suburb, railway: 50km/h

Test methods:

Automatic calling, each call lasts 60s, interval 10s,

MS calls fixed phone

Vehicle loss : 6 to 10dB


DT items

BCCH coverage test

TCH coverage test

Handover test on cell borders

Interference test

Indoor coverage test in special locations

Call quality test

Complaints test

……

DT Index

Coverage rate （ SUB ） Rx-Lev (>=-94dbm )/ Total samples×100 ％

Call completion rate

Call completion rate ＝ Success call / Call attempts×100 ％

Call drop rate

Call drop rate ＝ Call drop number/ Success number×100

％

Voice quality （ SUB ） Quality=0-4 level/ total samples×100 ％


DT for data service

WAP test

FTP test



Test mode

Idle mode: Cell selection and reselection, coverage

Automatic calling: Downlink level, quality and call

completion rate

Manual calling:

Frequency locking : Cell coverage and cell status

Compelling handover: Check whether handover can be

carried out among cells


DT examples-1

Get network running status and each r

adio parameters through continuous se

tting up calls.

Commonly recorded parameters includ

e BCCH, TCH, Rx Level, Rx Qual, Tx

Power, Time Advance, Time slot, BSIC,

Cell ID and adjacent cell BCCH, RxLe

vel.

Diagrams and tables to facilitate the an

alysis of network.


DT examples-2

Analyze handover according t

o RxLevel, RxQual and adjace

nt cell environment, to check

Pingpong handover and lonely

island

Location and analysis of some

practical events (such as call

drop, handover, etc.),


DT examples-3

Cell coverage range test

Lock frequency of test mobile phone

Interference test

Scanning receiver, calculate C/I, C/A.

Network borderland test

Handover strip , the change of BISC or LAC.


DT examples-4

Dual-band network reselection and handover

Cell reselection relationship on idle status

Handover relationship on busy status

Indoor coverage test

Portable DT device for indoor coverage test.

Ping-pong handover caused by nearby macro-cells


DT analysis result

RXLEV distribution chart and table

RXQUAL distribution chart and table

TA distribution chart and table

Interference from adjacent channel distribution chart

Main server area chart

Handover distribution chart

Location update distribution chart

……

Hello！ Speak louder！

Too much noise!

0063 goes up again…


Brief description of CQT

Call quality test, that is to choose a certain amount of

spots, and set up some calls in each spot.

Test items include call completion rate, call drop rate,

silent call, call quality, etc.


Principles for CQT

CQT test spots shall be as comprehensive as possible

Political hotspots: authority office, power building, etc.

Economic hotspots: shopping mall, office building, hotel,

restaurant, stock exchange, etc.

Cultural hotspots: exhibition, museum, theatre, scenic spot,

entertainment place, etc.

Transportation junction: airport, railway station, port, etc.

At least 80% indoor test


CQT KPI

Call completion ratio

Call completion ratio=total successful call / total call set up *100%

Call drop rate

Call drop rate = total call drop / total successful call * 100%

Voice intermittence rate

Voice intermittence rate= total voice intermittency / total successful

call * 100%

Silent call rate

Echo and background noise ratio

Cross talk ratio


CQT data test items

Attach Attach length, Attach success rate

PDP activation success rate Activation length, activation success rate

WAP test Homepage display time, WAP success rate

Ping test Average time delay, ping success rate

FTP download Download speed, RLC average throughput


CQT data test table


CQT mode

Generally, carry out MOC and MTC 10 times each and

every call lasts 1 minute

Test spots shall be even-distributed in test area

Two testers can call each other at the same place

Carry out data service test according to customer’s

demand

Record each test and fill them into tables

Contents





Evaluation result of network test

Network KPI

DT result

CQT result

Test instance analysis

Network development suggestion

忙时话务掉话比

5060708090

100110

9 3月日 9 4月日 9 5月日 9 6月日四天平均9 24月日 9 25月日 9 26月日 9 27月日四天平均

(%)切换成功率

84

89

94

99


( )(%)话音信道掉话率含切换

0. 5

0. 6

0. 7

0. 8

0. 9



Network KPI

Call drop rate

Handover success rate

TCH assignment success rate

Call drop rate of traffic

Radio access rate

Bad cell proportion

Cells’ names

Voice channel

congestion rate

Voice channel overflow

times

Total traffic of voice channel

Traffic in each channel

Total number of configured

voice channel

Carrier number

Cell2, Taxiu 4.82 250 6.4275 0.7356 12 2

Cell1, Hebei village, Tongde

20.82 297 3.8994 0.7798 5 1

Guide,Laxiwa23 5.49 59 24.9274 0.6579 41 6

Cell1,Guinan county

4.24 68 6.1386 0.7115 12 2

Cell1,Douhoulou

8.61 101 3.7319 0.6219 6 1


Congestion cells

Traffic in each channel is larger than 0.5 Erl

Coverage analysis

signalsample number Proportion

-75 to -0 4556 74.85%

-85 to -75 1459 23.97%

-95 to -85 72 1.18%

-110 to -95 0 0.00%

other 0 0.00%

area proportion whose signal

strength is higher than -85 98.82%

　


DT result-Coverage

Voice analysis

Error ratesample number Proportion

0 5653 96.62%

1 42 0.72%

2 36 0.62%

3 36 0.62%

4 19 0.32%

5 28 0.48%

6 32 0.55%

7 5 0.09%

Proportion of voice quality higher than 3 98.56%


DT result-Voice quality


CQT result

Voice test result

Test items

Test result

Ericsson ZTE

Transformer substation, Xue

fu

Educational building, Bayi Agriculture Univ

ersity

Longhu harbor1

Longhu harbor2

Attach test

GPRS Attach average time 1656ms 1619ms 2454ms 2468ms

GPRS Attach success rate(%)

100% 100% 100% 100%

PDP activation

test

PDP activation time 609ms 630ms 790ms 876ms

PDP activation success rate(%)

100% 100% 100% 100%

Ping test

Ping package size 300 bytes 128 bytes 128 bytes 300 bytes

Average time delay 2070ms 835ms 1162ms 1840ms

Success rate 100% 100% 100% 100%

FTP test Average download speed 3.63 KB/S 3.60 KB/S 3.57KB/S 3.60KB/S


CQT result

Data test result


Test instance analysis-1

Signal strength is weak in the red circle where has high bit errors.

BTS antenna is very high

In addition, phoenix trees flourish in these areas too



Signal strength is weak in the red circle where has high

error rate, call drop is induced there.



Signal strength is very low there and BSIC can’t be

decoded.



Generally, in dense urban, it is reasonable if TA value is lower

than 2; overshooting may happen if TA value is too high.



Handover requiring times:

167

Handover success times:

166

Handover failure times:1

Handover success rate:

99.40%

Frequent handover occurs

in many places of the

figure



Reason 1 for frequent handover: handover threshold is se

t improperly.



Reason 2 for frequent handover: signal strengths of adjacent cells a

re close to each other in areas where frequent handover occurs



Effective neighbor

cell means cells that

can be tested BISC

can be decoded.

We shall check

places whose

effective neighbor

cell is zero.

Co-channel interference analysis



On RXLEV and

RXQUAL figure

Good receiving

signal level but bad

voice quality.


Suggestions for network development

Collect and classify each chart, table

Propose suggestions of optimizing adjustment after comprehensive analysis

Engineering parameter adjustment

Frequency, neighbor cell adjustment

Radio parameter adjustment

……

Suggestions for network development Cell capacity expansion

Indoor distributed suggestion

Newly-built site suggestion

New round of network evaluation and optimization

gbo_011_e1_1 network quality evaluation zte university gsm-bss d&t team

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