GBO_011_E1_1 Network quality evaluation

Présentation au sujet: "GBO_011_E1_1 Network quality evaluation"— Transcription de la présentation:

1 GBO_011_E1_1 Network quality evaluation
ZTE University GSM-BSS D&T Team

2 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

3 Contents Network evaluation overview Network evaluation test
Test result and analysis

4 Concepts of network evaluation
Network evaluation overview Concepts of network evaluation Simulate subscribers calling process. Choose representative test samples Test on Um interface Test methods :DT and CQT 模拟用户测试网络性能,客观反映用户通话情况 以点带面,测试抽样必须具有代表性 主要是通过对Um口的测量来定位网络覆盖、干扰和容量等问题 测试手段主要有DT测试和CQT测试

5 Why network test evaluation?
Network evaluation overview Why network test evaluation? Discover network problems, GSM network evaluation include: MSC statistic analysis Radio network evaluation analysis 发现现有网络中存在的问题，对正在运行的网络进行评估和优化，以便更好地发挥现有网络设备的作用，为用户提供更好地服务 移动交换机统计分析和无线网络评估分析 Network quality is the chief factor to win the competition.

6 Probably problems in radio network
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. 频率资源紧张，复用方式紧密，同、邻频干扰增大 工程参数设计不合理（主要是RF参数） 无线资源参数设计不合理 站址选择不合理 重点路段和风景点的覆盖不尽人意 大型建筑物的室内覆盖信号较弱 杂音、断续等语音质量问题

7 Significance of network evaluation
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 整体了解自己网络和其他运营商的网络状况 发现网络存在的问题 给出优化、调整建议 加大运维力度，建设高质量的移动网络

8 Contents Network evaluation overview Network evaluation test
Test result and analysis

9 Network evaluation flow
Network evaluation test Network evaluation flow

10 Main contents of test Select test route and venue Test items
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 选择测试路线和测试地点 测试的主要内容 小区的覆盖范围 定位同邻频干扰源 TCH信道的检测 检查小区间的切换是否正常 跟踪第三层信令 用户投诉问题 选择测试的时间、人员和进度安排

11 Test schedule Network evaluation test TIME TEST SCHEDULE WEEK1 WEEK2
Mission MON TUE WED THR FRI SAT SUN Prepare documents Driving Test CQT Test analysis KPI collection KPI analysis Evaluation report Summary

12 Test and evaluation methods
Network evaluation test Test and evaluation methods DT（DRIVE TEST） CQT（CALL QUALITY TEST）

13 key points in DT Prepare documents for DT Prepare DT instruments
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 DT主要是指在一个区域中借助测试仪表、测试手机及测试车辆等工具沿特定路线进行进行全程拨打测试,通过所得无线环境参数以及呼叫接通情况和测试者对通话质量的评估，为网络的规划、工程、运维等部门提供较为完备的网络覆盖、干扰资料，为网络的优化和后续建设提供依据。 做好测试的前期资料准备工作 选择功能完备的测试设备 选择有代表性的测试路线 选择合适的测试时间(一般在忙时) 制定合理的测试方法 提供丰富的测试分析报告

14 Main documents for DT Digital map (MAPINFO, etc.)
Network evaluation test Main documents for DT Digital map (MAPINFO, etc.)

15 Main documents for DT Site and cell data
Network evaluation test Main documents for DT Site and cell data Site name, frequency, antenna data, neighbor cell, longitude, latitude … 站点名称、经纬度数据、频点配置数据、天线挂高、下倾数据、邻小区关系数据……

16 Network evaluation test
Main documents for DT Traffic data in 24 hours

17 Network evaluation test
Main documents for DT GPS, Test handset, DT software, SIM card, vehicle, power, laptop … 测试设备准备：GPS、测试手机、笔记本、测试软件、SIM卡、电源、车辆等

18 DT route selection Highway from airport to downtown
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 机场至市区路段，高速公路覆盖地段 本市主要交通干线 其它用户投诉较为严重路段 本市话务热点地区、重点地区环线路段

19 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

20 Test method of DT Vehicle speed: Test methods:
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

21 DT items BCCH coverage test TCH coverage test
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 ……

22 DT Index Coverage rate（SUB） Call completion rate Call drop rate
Network evaluation 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％

23 Network evaluation test
DT for data service WAP test FTP test

24 Test mode Idle mode: Cell selection and reselection, coverage
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 空闲模式：可以测试小区选择和重选，对网络覆盖情况有一个大致了解； 自动拨打测试：可以对全网的下行电平、下行质量、接通率等项目进行统计； 手动拨打通话测试：采用手动拨打通话测试可以测试到自动拨打情况，而采用自动拨打通话测试可能会有所遗漏； 锁频测试：通过锁频测试，对小区的覆盖范围、小区情况进行测试； 强制切换：这种测试方式主要是针对小区间能否切换进行确认。

25 Network evaluation test
DT examples-1 Get network running status and each radio parameters through continuous setting up calls. Commonly recorded parameters include BCCH, TCH, Rx Level, Rx Qual, Tx Power, Time Advance, Time slot, BSIC, Cell ID and adjacent cell BCCH, RxLevel. Diagrams and tables to facilitate the analysis of network.

26 Network evaluation test
DT examples-2 Analyze handover according to RxLevel, RxQual and adjacent cell environment, to check Pingpong handover and lonely island Location and analysis of some practical events (such as call drop, handover, etc.),

27 DT examples-3 Cell coverage range test Interference test
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. 小区覆盖范围测试 将测试手机锁定该小区频点，禁止话机重选或切换到相邻小区，开车向小区覆盖边缘行驶，以了解当前小区最大覆盖范围 干扰测试 在通话的过程中扫频接收机对BCCH、TCH进行高速扫频，计算出载干比，发现同、邻频干扰并且进行定位 不同地区网络边界带测试 在两个地区边界进行手机通话测试，通过观测BSIC或LAC的变化，发现两个网络的切换带，通过这种测试，结合扫频数据，掌握两地网络的边界带

28 DT examples-4 Dual-band network reselection and handover
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 双频网重选和切换测试 通过双频手机的IDLE与通话路测，发现双频手机在双频网之间的小区重选与切换关系。结合小区设计参数，对小区重选和切换关系进行调整，使双频话务分担更加合理 室内覆盖测试 通过便携式室内覆盖路测设备，对重要建筑物的室内覆盖状况进行测试 对于高层楼房由于附近宏蜂窝辐射信号与室内微蜂窝信号造成的乒乓切换，需要通过扫频测试掌握干扰来源进行调整

29 DT analysis result RXLEV distribution chart and table
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 ……

30 Brief description of CQT
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. Hello！Speak louder！ Too much noise! 0063 goes up again… 

31 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

32 CQT KPI Call completion ratio Call drop rate Voice intermittence rate
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

33 CQT data test items Attach PDP activation success rate WAP test
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

34 Network evaluation test
CQT data test table

35 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

36 Contents Network evaluation overview Network evaluation test
Test result and analysis

37 Evaluation result of network test
Test result and analysis Evaluation result of network test Network KPI DT result CQT result Test instance analysis Network development suggestion

38 Network KPI Call drop rate Handover success rate
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

39 Congestion cells Traffic in each channel is larger than 0.5 Erl
Test result and analysis Congestion cells Traffic in each channel is larger than 0.5 Erl 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 0.6579 41 6 Cell1,Guinan county 4.24 68 6.1386 0.7115 Cell1,Douhoulou 8.61 101 3.7319 0.6219

40 area proportion whose signal strength is higher than -85
Test result and analysis DT result-Coverage Coverage analysis signal sample number Proportion -75 to -0 4556 74.85% -85 to -75 1459 23.97% -95 to -85 72 1.18% -110 to -95 0.00% other area proportion whose signal strength is higher than -85 98.82%

41 DT result-Voice quality
Test result and analysis DT result-Voice quality Voice analysis Error rate sample number Proportion 5653 96.62% 1 42 0.72% 2 36 0.62% 3 4 19 0.32% 5 28 0.48% 6 32 0.55% 7 0.09% Proportion of voice quality higher than 3 98.56%

42 Test result and analysis
CQT result Voice test result

43 CQT result Data test result Test result and analysis Test items
Ericsson ZTE Transformer substation, Xuefu Educational building, Bayi Agriculture University Longhu harbor1 Longhu harbor2 Attach test GPRS Attach average time 1656ms 1619ms 2454ms 2468ms GPRS Attach success rate(%) 100% PDP activation test PDP activation time 609ms 630ms 790ms 876ms PDP activation success rate(%) Ping test Ping package size 300 bytes 128 bytes Average time delay 2070ms 835ms 1162ms 1840ms Success rate FTP test Average download speed 3.63 KB/S 3.60 KB/S 3.57KB/S 3.60KB/S

44 Test instance analysis-1
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

45 Test instance analysis-2
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.

46 Test instance analysis-3
Test result and analysis Test instance analysis-3 Signal strength is very low there and BSIC can’t be decoded.

47 Test instance analysis-4
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.

48 Test instance analysis-5
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

49 Test instance analysis-6
Test result and analysis Test instance analysis-6 Reason 1 for frequent handover: handover threshold is set improperly.

50 Test instance analysis-7
Test result and analysis Test instance analysis-7 Reason 2 for frequent handover: signal strengths of adjacent cells are close to each other in areas where frequent handover occurs

51 Test instance analysis-8
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.

52 Test instance analysis-9
Test result and analysis Test instance analysis-9 Co-channel interference analysis On RXLEV and RXQUAL figure Good receiving signal level but bad voice quality.

53 Suggestions for network development
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

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