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Proprietary and confidential

DRIVE TEST

REQUIREMENTS

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REQUIREMENT FOR DRIVE TESTING

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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.

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DRIVE TEST PROCESS

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Drive Test Setup

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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.

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Drive test types:

Drive test can be categorized in three types

Routine drive test

Problem specific drive test

Cell coverage analysis drive test

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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.

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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.

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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.

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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

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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.

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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.

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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.

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DRIVE TEST OUTPUTS

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Using the drive test equipment we can monitor the following

Status Information

Error reports

Mode reports

Layer 2 messages Layer 3 messages

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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.

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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.

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MEASUREMENT METRICS

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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)

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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)

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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

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DRIVE TEST ANALYSIS

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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%

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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%

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NEPTUNE AND PROBE

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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 .

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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

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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

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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.

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Statistical Reporting

Once a file is loaded,NEPTUNE will automaticallygenerate a statisticalsummary enabling theimprovement of ongoingsystem engineering to bemeasured.

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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

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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

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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

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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 .

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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.

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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

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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.

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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

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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

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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

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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

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Network Quality and Efficiency Factor

Information from all the above KeyPerformance Indicators arecombined to provide:

Network Performance Indicators

Network Quality and EfficiencyFactor

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EXPANSION STRATEGY

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Following needs to be defined

1.Propagation model

2.Coverage model

3.Traffic model

4.Service model

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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.

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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.

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