208347053-Drive-Test
Transcript of 208347053-Drive-Test
-
8/12/2019 208347053-Drive-Test
1/60
Proprietary and confidential
DRIVE TEST
REQUIREMENTS
-
8/12/2019 208347053-Drive-Test
2/60
Proprietary and confidential
REQUIREMENT FOR DRIVE TESTING
-
8/12/2019 208347053-Drive-Test
3/60
Proprietary and confidential
OMC statistics provide an efficient means of evaluatingperformance of the entire network. However in addition to this it isextremely valuable to conduct drive test performancemeasurements for the following reasons:
Test the network from the subscribers point of view Test the complete system, end-to-end (mobile-to-land) Benchmark performance against competitor networks Test specific important routes and areas Test in-building coverage for specific buildings (walk test)
AIRCOM International can conduct drive test data collection andanalysis using the NEPTUNE drive test tool, and can providecomprehensive reports supporting all of the above requirements.This includes detailed competitor analysis and benchmarkingsupported by the PROBE benchmarking tool.
-
8/12/2019 208347053-Drive-Test
4/60
Proprietary and confidential
DRIVE TEST PROCESS
-
8/12/2019 208347053-Drive-Test
5/60
-
8/12/2019 208347053-Drive-Test
6/60
Proprietary and confidential
Drive Test Setup
-
8/12/2019 208347053-Drive-Test
7/60
Proprietary and confidential
Drive test routes should be chosen to be representative of the part of thenetwork under study, covering a range of different coverage areas (urban,suburban, etc.).
If possible simultaneously collect GSM speech and GPRS drive test data. Drive test to be carried out during normal daylight hours to reflect normal
network load conditions.
Calls to be made preferably mobile-to-PSTN. Call duration to be equal to the average call duration for the network, as
derived from OMC statistics. Allow 10s idle time between calls. GPRSdata calls to be set according to the average data call length for thenetwork.
At least 1000 calls required for good statistical confidence.
-
8/12/2019 208347053-Drive-Test
8/60
Proprietary and confidential
Drive test types:
Drive test can be categorized in three types
Routine drive test
Problem specific drive test
Cell coverage analysis drive test
-
8/12/2019 208347053-Drive-Test
9/60
Proprietary and confidential
Routine drive test
Optimization is a ongoing process and the network needs to be monitoredon a daily basis.
Routine drive test forms a integral part of this process.
Drive test routes are decided by the Network operator and these routes areregularly drive tested and any problems found are reported.
These problems are then further analyzed and solved.
Hence it is important that these drive test routes are selected carefully.
Drive test routes should include all the major road, important location,airports etc.
Also they should be able to cover most of the cells.
Each drive test route should be typically 2 - 3 hours long.
-
8/12/2019 208347053-Drive-Test
10/60
Proprietary and confidential
Typical Optimization process using routine drive testing
The drive test routes must be decided by the operator and a priority set onthe routes for testing.
The drive test routes are usually 2 - 3 hours in duration in order to ensurethat the data generated is of a manageable size.
The drive test teams use the Test Mobile equipment (e.g.TEMS) to maketest calls to the MSC test number on the network of 2 minute duration witha 15 second break.
All data is logged on the computer, location information is also taken usinga GPS receiver.
During or after completion of the drive test route, analysis of the datacollected is performed to identify areas of dropped or noisy calls.
This will be done using FICS or other similar software.
-
8/12/2019 208347053-Drive-Test
11/60
Proprietary and confidential
Should the analysis of the route indicate problems of either dropped ornoisy calls then with the aid of the RF design and Database parameters,an assessment is made to identify the possible source of interferencecausing the noisy or dropped call.
If a call is dropped and no interference is present a retest is made in thesame area, if the scenario of the dropped call can be repeated, theidentity of the problem cell will be obtained and corrective action taken.
To assist in confirming possible sources of interference there may be arequirement to remove the suspected interfering channel.
This would be done by the optimisation engineers. The suspected interfering carrier would be removed temporarily from
service and test calls made again in the problem area, this would show if
the interference had been removed. The process for temporarily removing carriers would have to be agreed
with the operator, this usually varies as to the importance of the cell as towhat time of day it can be taken out of service.
-
8/12/2019 208347053-Drive-Test
12/60
Proprietary and confidential
After conformation as to what is causing the problem with the drive testroute, the drive test engineer will attempt to find a solution to the problem.
This can be one of a number of possibilities i.e. Power Change to BTS,Frequency Plan change, Neighbor addition required, etc.
Once a possible solution to the problem has been found it may be possiblein some circumstances to immediately attempt the solution via the OMC,this usually relates to minor database changes and adding neighbors.
The solution is implemented and proven immediately. If the problem is rectified the change remains in place and a change request
is raised for the solution for the purpose of keeping records of all changes inthe network.
If the solution requires a major database change or antenna work a changerequest must be raised via the Optimization Control Engineers.
After the solution is implemented a retest of the problem area is carried outto confirm the problem has been solved
-
8/12/2019 208347053-Drive-Test
13/60
Proprietary and confidential
Problem drive testing Any problem reported by statistical analysis, routine drive testing, customer
care centre , alarms need to be analyzed in detail to find a solution. Problem specific drive testing is a important tool which helps us do it. Here we make a list of problematic cell and drive test them thoroughly to
analyze the problem.
There may be many different methods which a optimization engineer mayemploy for the analysis. As an example, if a particular cell is being interfered the frequency of the
cell may be changed temporarily to identify the interferer. Also the levels and TA at which the cell is being interfered may be analyzed.
Here the data collection and analysis are done simultaneously.
-
8/12/2019 208347053-Drive-Test
14/60
Proprietary and confidential
Cell Coverage Analysis Drive Test It has been found that normally that the coverage and server area of the
cells differ from the planned area. Hence it is often found that new cells that come on air serve far more or
much less area than initially planned and same could be the case with thecoverage.
This could lead to two problems. If the server area is less than planned itcould lead to coverage holes or poor cover areas. If the coverage area ismore than planned it may cause interference in the network.
Hence it is important that once new cells come on air they must bethoroughly drive tested to determine their server and coverage areas.
If any major deviation from the initially planned design is found the cellsites should be optimized.
-
8/12/2019 208347053-Drive-Test
15/60
-
8/12/2019 208347053-Drive-Test
16/60
Proprietary and confidential
Optional Features Some drive test equipment provide supplementary features which help
during drive test. Map displaying the drive tested area showing the major roads, location, cell
sites is provided ,this helps us to be always aware as to where we are in thenetwork.
Also some vendors provide spectrum analyzer which helps in finding theinterfering frequencies and to find clear frequencies.
-
8/12/2019 208347053-Drive-Test
17/60
Proprietary and confidential
DRIVE TEST OUTPUTS
-
8/12/2019 208347053-Drive-Test
18/60
Proprietary and confidential
Using the drive test equipment we can monitor the following
Status Information
Error reports
Mode reports
Layer 2 messages Layer 3 messages
-
8/12/2019 208347053-Drive-Test
19/60
Proprietary and confidential
Status Information
In status information we get the following information
General Information: This includes the Latitude ,longitude data,server call name, Marker ,data, time , log file name etc.
Serving cell: This includes Cell Identity, BSIC, ARFCN ,MCC,MNC, LAC.
Serving + Neighbor cell data: This includes CI, BSIC, ARFCN,Rxlev, C1 and C2 for the serving and the best 6 neighbors.
Dedicated channel: This includes data such as Channel number,Timeslot number, Channel type and TDMA offset,hopping
information and channel mode. Radio Environment: This includes serving cell,lat , long, rxlev,
rxqual, TA, DTX and RL Timeout counter information.
-
8/12/2019 208347053-Drive-Test
20/60
Proprietary and confidential
Error reports
If any errors are reported during the call they can be analyzed from thisreport.
Mode reports
These are the channel mode reports.
Layer 2 messages
All the layer 2 messages can be analyzed.
Layer 3 messages
All the layer 3 messages can be analyzed.
-
8/12/2019 208347053-Drive-Test
21/60
Proprietary and confidential
MEASUREMENT METRICS
-
8/12/2019 208347053-Drive-Test
22/60
Proprietary and confidential
GSM Drive Test MetricsGSM drive test data can be presented in a number of ways. A combination of graphical presentation and
statistical analysis is recommended.The examples below show measurements for 2 networks for comparison purposes.Graphical Presentation
The following parameters can be displayed on a map, allowing the visualisation of specific problems bylocation:
Route PlotsRxLev F ull: Route Coverage Plot RxL ev Sub: Route Coverage Plot (excluding dummy bursts during DTX operation)RxQual F ull : Route Quality PlotRxQual Sub: Route Quality Plot (excluding dummy bursts during DTX operation)FER: Route Frame Erasure Rate PlotM S TX Power : Route plot of Mobile Transmit PowerSQI Plot: Route Plot of Speech Quality Index (or equivalent, if available)
EventsEvents plots may be superimposed on one of the above route plots, eg. RxLev or RxQual.
Call D rops: Plot of dropped call eventsSetup F ail ur es: Plot of call setup failure eventsH O Failu res: Plot of Handover Failure eventsH O Success: Plot of Successful Handover events (if required)
-
8/12/2019 208347053-Drive-Test
23/60
Proprietary and confidential
GPRS Drive TestGPRS drive test data can be presented in a number of ways, much the same as GSM drive test data. Acombination of graphical presentation and statistical analysis is recommended.
Graphical PresentationThe following parameters can be displayed on a map, allowing the visualisation of specific problems bylocation:
Route PlotsUL /DL RLC Throughput: Radio Link Layer data throughputUL /DL L LC Throughput: Logical Link Layer throughput (user data)UL /DL RLC Block Error Rate (BLER): Radio Link Block Error Rate
UL /DL RLC Retransmission Rate: Radio Link Retransmission RateUL /DL Coding scheme used (CS1-4): Allocated Coding SchemeUL /DL Number of ti meslots used: Allocated timeslots
EventsEvents plots may be superimposed on one of the available route plots, eg. RxLev, RxQual, RLCthroughput, etc.PDP Context Activation Fai lu re: Failure to activate PDP Context (Packet Data Protocol)PDP Context L oss: Loss of PDP Context (GPRS Call Drop)
-
8/12/2019 208347053-Drive-Test
24/60
Proprietary and confidential
Additional GPRS MetricsThe following metrics are also useful, if available:UL /DL TCP Throughput UL /DL U DP Throughput Delay (L atency) UL /DL /Round-tri p I P Packet L oss Rate Jitter
-
8/12/2019 208347053-Drive-Test
25/60
Proprietary and confidential
DRIVE TEST ANALYSIS
-
8/12/2019 208347053-Drive-Test
26/60
Proprietary and confidential
Following types of analysis are carried out:
Coverage Analysis Level AnalysisQuality Analysis
Interference Analysis: To identify co-channel and adjacent channelinterference related problem
Handover Analysis Neighbour Analysis: To identify missing neighbours.Call Analysis: To check network performance against predefined
KPIs like DCR,CSSR,CSR,Call Setup time,Callhold time etc.
Layer 2 AnalysisLayer 3 Analysis
-
8/12/2019 208347053-Drive-Test
27/60
Proprietary and confidential
RxLev Distribution
RxLev Distribution
0
500000
1000000
1500000
2000000
2500000
3000000
3500000
4000000
4500000
0-10 11-20 21-30 31-40 41-50 51-60 61-70
RxLev
N u m
b e r o
f M e a s u r e m e n
t s
Network A
Network B
-
8/12/2019 208347053-Drive-Test
28/60
Proprietary and confidential
RxQual Distribution
RxQual Distribution
0
2000000
4000000
6000000
8000000
10000000
12000000
R x Q u
a l 0
R x Q u
a l 1
R x Q u
a l 2
R x Q u
a l 3
R x Q u
a l 4
R x Q u
a l 5
R x Q u
a l 6
R x Q u
a l 7
N u
m b e r o f M e a s u
r e m e n t s
Network A
Network B
-
8/12/2019 208347053-Drive-Test
29/60
Proprietary and confidential
FER DistributionFrame Erasure Rate Distribution
0
2000000
4000000
6000000
8000000
10000000
12000000
0-10 11-20 21-30 31-40 41-50 51-60 61-70 71-80 81-90 91-100
FER
N u m
b e r o
f M e a s u r e m e n
t s
Network A
Network B
-
8/12/2019 208347053-Drive-Test
30/60
Proprietary and confidential
MS TX Power
Mobile Transmit Power Distribution
0
1000000
2000000
3000000
4000000
5000000
6000000
7000000
8000000
9000000
10000000
33 31 29 27 25 23 21 19 17 15 13
MS TX Power
N u m b e r o f m e a s u r e m e n t s
Network A
Network B
-
8/12/2019 208347053-Drive-Test
31/60
Proprietary and confidential
Access Failure Rate (1-Call
Setup Success Rate )Access Failure Rate %
9.8%
8.2%
0.0%
2.0%
4.0%
6.0%
8.0%
10.0%
12.0%
Network A Network B
%of AccessAttempts
-
8/12/2019 208347053-Drive-Test
32/60
Proprietary and confidential
Blocked Call Rate
Blocked Calls and No Service [%]
0.3% 0.2%
9.5%
8.0%
0%
2%
4%
6%
8%
10%
12%
Network A Network B
No Service Attempts Blocked Calls
-
8/12/2019 208347053-Drive-Test
33/60
Proprietary and confidential
Call Drop Rate
Dropped Call Rate %
2.9%
1.3%
0.0%
0.5%
1.0%
1.5%
2.0%
2.5%
3.0%
3.5%
Network A Network B
%of Comp
letedCalls
-
8/12/2019 208347053-Drive-Test
34/60
Proprietary and confidential
Handover Failure Rate
Handover Summary
11761444
35
12
0
200
400
600
800
1000
1200
1400
1600
Network A Network B
Number of Handover
Handover completed Handover failed
-
8/12/2019 208347053-Drive-Test
35/60
Proprietary and confidential
Average SQI
Average Speech Quality Index (SQI)
19.3 19.1
0.0
3
6
9
12
15
18
21
24
Network A Network B
SQI
-
8/12/2019 208347053-Drive-Test
36/60
Proprietary and confidential
DL RLC Throughput (bytes/sec)vs DL RLC BLER
0
1000
2000
3000
4000
5000
6000
0 6 1 2 1 8 2 6 3 3 4 1 5 2 6 3 8 3
90%50%
10%
-
8/12/2019 208347053-Drive-Test
37/60
Proprietary and confidential
DL LLC Throughput (bytes/sec)
vs DL RLC BLER
0
500
1000
1500
2000
2500
3000
3500
4000
4500
0 6 1 2 1 8 2 6 3 3 4 1 5 2 6 3 8 3
90%
50%10%
-
8/12/2019 208347053-Drive-Test
38/60
Proprietary and confidential
NEPTUNE AND PROBE
-
8/12/2019 208347053-Drive-Test
39/60
Proprietary and confidential
NEPTUNE is a sophisticated test and diagnosticoptimization tool on the market and, uniquely, doesnot simply collect, log and display the necessary data,but also suggests possible causes and solutions toany problems.
NEPTUNE can be used for GSM900, 1800, 1900 andDual Band and GPRS technologies, fully supportingdual-mobile tests and measurement such asGSM900/DCS1800 or GSM1900 .
-
8/12/2019 208347053-Drive-Test
40/60
Proprietary and confidential Commercial-in-Confidence
Features State-of- the-art PC based optimization tool delivering real time
analysis capabilities. User friendly with intuitive menu structure making it ideal for bothreal-time and post measurement analysis.
Automatic fault finding and problem solving diagnostic capabilities
Live call analysis Statistical and graphical display
Long and short term cost savings due to competitive pricing and thesubstantial shortening of the optimization process.
It also supports additional testmobile formats, which can be loadedand analyzed
-
8/12/2019 208347053-Drive-Test
41/60
-
8/12/2019 208347053-Drive-Test
42/60
Proprietary and confidentialCommercial-in-Confidence
AnalysisIn terms of data analysis, NEPTUNE provides:
Full summary of actual signalcoverage (RXLev)
Full summary of received quality(RXQual)
Enhanced handover performanceand level distribution calculations
Statistical Analysis
Replay & Analysis
Call Success
-
8/12/2019 208347053-Drive-Test
43/60
Proprietary and confidentialCommercial-in-Confidence
Call Analysis
NEPTUNE can analyze live calls, call success, signal levelsand call quality and provide separate graphical displays onthe 2D Map View in real time.
NEPTUNE also incorporates the following features - meanand worst call levels, quality, detailed comparativesummary of cells signal strengths, analysis of sites whichutilize the co-channel and adjacent channels and resultsof co-channel and adjacent channel interference. The usermay define thresholds for acceptable signals and qualitylevels.
-
8/12/2019 208347053-Drive-Test
44/60
Proprietary and confidentialCommercial-in-Confidence
Statistical Reporting
Once a file is loaded,NEPTUNE will automaticallygenerate a statisticalsummary enabling theimprovement of ongoingsystem engineering to bemeasured.
-
8/12/2019 208347053-Drive-Test
45/60
Proprietary and confidentialCommercial-in-Confidence
Handover Analysis All handovers are analysed and problems are identified.Foreach problem, causes and solutions are suggested.NEPTUNE examines handovers in great detail:
Problem areas are automatically identified
Handover success/failure is shown on routePosition failure is located on XY graph
Cause/solution proposed for each failure
Step-by-step replay control allows every stageof handover to be broken down for detailedanalysis
Forced Handover
-
8/12/2019 208347053-Drive-Test
46/60
Proprietary and confidentialCommercial-in-Confid
Neighbour Analysis
NEPTUNE summarizes critical information relating to theneighbour relations and, once a problem is perceived, willprovide the following:
The serving cells ID and full
geographic location The ID and full geographic locationof the Neighbour cells that are eithermissing or have not been measured
Problem areas are separatelydisplayed on the 2D map view
-
8/12/2019 208347053-Drive-Test
47/60
Proprietary and confidentialCommercial-in-Confidence
Diagnostic Capabilities
NEPTUNE is the only system to provide automaticfaultfinding and problem solving diagnostic capabilities. Fulllocation and proposed solutions are provided for:
Low signal level
Poor speech quality
Failed handovers
Missing system neighbour definitions
-
8/12/2019 208347053-Drive-Test
48/60
Proprietary and confidentialCommercial-in-Confidence
Testmobile Import Facilities
NEPTUNE allows import of additional file formats(GSM and TETRA) in order to undertake analysisof data collected from other systems. Forexample:
TEMS Investigator
TOM Measurement System
GPRS and HSCSD, Nemo technologies
GSM log files from X-PLOR ANT units .
-
8/12/2019 208347053-Drive-Test
49/60
Proprietary and confidentialCommercial-in-Confidence
PROBE
PROBE is an add on module to Neptune that a gives youthe ability to perform time-based, operator based anddistance based analyses. As a network analysis tool,PROBE differs from the existing analysis functionality ofNeptune because the statistics generated show thesystem s problems as a whole rather than pin -pointingeach and every problem.
-
8/12/2019 208347053-Drive-Test
50/60
Proprietary and confidentialCommercial-in-Confidence
Features
Ideal for both real-time and post measurement analysis Displays a networks Key Performance Indicators
Key Performance Indicators are combined to produce theNetwork Quality and Efficiency Factor
Statistical and graphical display
Long and short term cost savings due to competitivepricing and the substantial shortening of the optimization
process Flexible hardware option
-
8/12/2019 208347053-Drive-Test
51/60
Proprietary and confidentialCommercial-in-Confidence
SPECIFIC FUNCTIONS OF PROBEHandover Statistics
Handover describes the change in the servingcell for the mobile when the handover marginfor the received level is achieved. PROBEprovides information regarding:
Handover Distribution - The number of
Inter and intra cell handovers attempted,completed and failed
Handover Performance - Inter and intracell success rate and the total HOsuccess rate
Number of Handovers per call - Thenumber of handovers that occurred percall within the testmobile survey.
-
8/12/2019 208347053-Drive-Test
52/60
Proprietary and confidentialCommercial-in-Confidence
Level Statistics
The level statistics refer to the received signal level for amobile:
Level (Full) Distribution (between -46 and -110)
Level (Sub) Distribution (between -46 and -110)
Cumulative Level Distribution
Level Banding
-
8/12/2019 208347053-Drive-Test
53/60
Proprietary and confidentialCommercial-in-Confidence
Quality Statistics
These provide with importantsystem level information aboutthe received quality:
Quality full and Sub distributionfor both hopping and non-hopping samples
Cumulative Quality Distribution
Interference
-
8/12/2019 208347053-Drive-Test
54/60
Proprietary and confidentialCommercial-in-Confidence
Call Statistics
Offer similar functionality to the call success analysisperformed for every survey in NEPTUNE
Call Distribution - Evaluates every call andcategorizes it as a Good Call or a No setup call
Call Holding Time - Displays the duration of each call.
Call Performance - Details for the Setup rate, Failurerate and Release rate.
Call Setup - Time Distribution Call Timers
-
8/12/2019 208347053-Drive-Test
55/60
Proprietary and confidentialCommercial- in-Confide nce
Cell Statistics
Important statistics for all the cells that were observedwithin a survey are provided.
Cell Domination
Cell poor Quality Distribution Cell Average Quality Distribution
Cell Average Level Distribution
Cell Mean Call Holding Time Cell average TA Distribution
-
8/12/2019 208347053-Drive-Test
56/60
Proprietary and confidentialCommercial-in-Confidence
Network Quality and Efficiency Factor
Information from all the above KeyPerformance Indicators arecombined to provide:
Network Performance Indicators
Network Quality and EfficiencyFactor
-
8/12/2019 208347053-Drive-Test
57/60
Proprietary and confidential
EXPANSION STRATEGY
-
8/12/2019 208347053-Drive-Test
58/60
Proprietary and confidential
Following needs to be defined
1.Propagation model
2.Coverage model
3.Traffic model
4.Service model
-
8/12/2019 208347053-Drive-Test
59/60
Proprietary and confidential
1.Propagation model- A model needs to be defined which is used to
simulate the propagation characteristics of the environment.
2.Coverage model-Based upon the link budget various coveragethresholds need to be defined for various clutter categories.
3.Service model-Based upon the requirements a service model is definedwhich will enlist the services to be provided like voice,data,SMS,VMSetc.
4.Traffic model-This model gives a description of the traffic growth thatneeds to be implemented vis a vis service model and demographicdistribution of subscriber.Traffic model also gives an idea about themE/sub for a region for different offered services.
-
8/12/2019 208347053-Drive-Test
60/60
Based upon all the models an Expansion strategy is formulated.Theexpansion strategy should meet the following objectives:
1. The new areas should be provided adequate coverage based upon thecoverage model.
2. The congestion which is existing in the network should be removed by proposing Delta sites which are over and above the traffic which needs to be distributed for expansion.
3.Based upon the traffic model new sites should be proposed.Demographic distribution of the data should be done based upon existing
traffic and by mapping the additional sites on the hotspots.
4.The KPIs set for the network should be met after addition of the newsites.Hence the network needs to be optimised.