GBO_011_E1_1 Network quality evaluation ZTE University GSM-BSS D&T Team.
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Transcript of 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 evaluation overview
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
Network evaluation overview
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.
Network evaluation overview
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
Network evaluation overview
Contents
Network evaluation overview
Network evaluation test
Test result and analysis
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
Network evaluation test
Network evaluation test
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
Network evaluation test
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 )
Network evaluation test
Network evaluation 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.)
Network evaluation test
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
Network evaluation test
Main documents for DT
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
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900M ERL( ) 1800M ERL( ) 合计
Network evaluation test
Main documents for DT
Traffic data in 24 hours
Network evaluation test
Main documents for DT
GPS, Test handset, DT software, SIM card, vehicle, power,
laptop …
Network evaluation test
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
Network evaluation test
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
Network evaluation test
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
Network evaluation test
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 %
Network evaluation test
DT for data service
WAP test
FTP test
Network evaluation test
Network evaluation 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
Network evaluation test
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.
Network evaluation test
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.),
Network evaluation test
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.
Network evaluation test
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
Network evaluation test
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…
Network evaluation test
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.
Network evaluation test
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
Network evaluation 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
Network evaluation test
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
Network evaluation test
CQT data test table
Network evaluation test
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
Network evaluation overview
Network evaluation test
Test result and analysis
Test result and analysis
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
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
( )(%)话音信道掉话率 含切换
0. 5
0. 6
0. 7
0. 8
0. 9
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
Test result and analysis
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
Test result and analysis
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%
Test result and analysis
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%
Test result and analysis
DT result-Voice quality
Test result and analysis
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
Test result and analysis
CQT result
Data test result
Test result and analysis
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
Test result and analysis
Test instance analysis-2
Signal strength is weak in the red circle where has high
error rate, call drop is induced there.
Test result and analysis
Test instance analysis-3
Signal strength is very low there and BSIC can’t be
decoded.
Test result and analysis
Test instance analysis-4
Generally, in dense urban, it is reasonable if TA value is lower
than 2; overshooting may happen if TA value is too high.
Test result and analysis
Test instance analysis-5
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
Test result and analysis
Test instance analysis-6
Reason 1 for frequent handover: handover threshold is se
t improperly.
Test result and analysis
Test instance analysis-7
Reason 2 for frequent handover: signal strengths of adjacent cells a
re close to each other in areas where frequent handover occurs
Test result and analysis
Test instance analysis-8
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
Test result and analysis
Test instance analysis-9
On RXLEV and
RXQUAL figure
Good receiving
signal level but bad
voice quality.
Test result and analysis
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