DRIVE TEST

Contents

• NETWORK PROBLEM IDENTIFICATION• REQUIREMENT FOR DRIVE TESTING• DRIVE TEST PROCESS• DRIVE TEST OUTPUTS• MEASUREMENT METRICS• DRIVE TEST ANALYSIS• NEPTUNE AND PROBE

Network Problem Identification

• Drive Test

• OMC Statistics

• Customer feedback

Requirement for Drive testing

• 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)

Drive Test Process

Drive Test Equipments

• Data collected to find and analyze problems in the network

• Equipment Necessary for Drive testing

VehicleDrive test mobile phone External vehicle mounted GPSLaptop with drive test software and GPS connection capability

Drive Test Setup

General Consideration

• Routes chosen to be representative of the part of the network under study

• If possible simultaneously collect GSM speech and GPRS drive test data

• Drive test to be carried out during normal daylight hours

• Calls to be made preferably mobile-to-PSTN

• Call duration to be equal to the average call duration for the network

• At least 1000 calls required for good statistical confidence 

Drive Test Types

• Routine drive test

• Problem specific drive test

• Cell coverage analysis drive test

Routine Drive Test

• Network to be monitored on a daily basis • Drive test routes to include all the major roads, important locations, etc• Routes regularly drive tested and problems further analyzed and solved• May require removing interfering carrier, Power Change to

BTS, Frequency Plan change, Neighbor addition , etc.

Problem Drive Testing

• Problems reported by statistical analysis, routine drive testing, customer care centre , alarms,etc

• Requires problem specific drive testing

• List of problematic cells identified and drive tested thoroughly to analyze the problem

• Data collection and analysis done simultaneously

Cell Coverage Analysis Drive Test

• Usually carried out for new planned sites in the network

• New cells to come on air are thoroughly drive tested to determine their server and coverage areas

• Optimisation to be carried out for any major deviation from the initially planned design

Optional Features

• Walk test support

• On line map display of the route

• Scan feature

Drive Test Outputs

Display

• Using the drive test equipment we can monitor the following o Status Informationo Error reportso Layer 2 messageso Layer 3 messages

Display….. Status Information• General Information: Includes Latitude ,longitude data, server call

name, Marker ,data, time , log file name etc• Serving cell: Includes Cell Identity, BSIC, ARFCN ,MCC, MNC, LAC• Serving + Neighbor cell data: Includes CI, BSIC, ARFCN, Rxlev• Dedicated channel:Includes Channel number, Timeslot number,

Channel type,hopping information • Radio Environment: Includes serving cell, Rxlev, Rxqual, TA, DTX

and RL Timeout counter information

Display…..

Error reports• Errors reported during a call can be analyzed from this report

Layer 2 messages• Layer 2 messages can be analyzed

Layer 3 messages• Layer 3 messages can be analyzed

Measurement Metrics

GSM Drive Test Metrics

• Route PlotsRxLev Full RxLev Sub RxQual FullRxQual SubFER MS TX PowerSQI

• Events Call Drops Setup Failures HO Failures HO Success

GPRS Drive Test Metrics

• Route Plot UL/DL RLC Throughput: Radio Link Layer data throughput

UL/DL LLC Throughput: Logical Link Layer throughput (user data)UL/DL RLC Block Error Rate (BLER): Radio Link Block Error RateUL/DL RLC Retransmission Rate: Radio Link Retransmission RateUL/DL Coding scheme used (CS1-4): Allocated Coding SchemeUL/DL Number of timeslots used: Allocated timeslots

• Events PDP Context Activation Failure: Failure to activate PDP Context (Packet

Data Protocol)PDP Context Loss: Loss of PDP Context (GPRS Call Drop)

Drive Test Analysis

Analysis Types

• Coverage Analysis: Level AnalysisQuality Analysis

• Interference Analysis: Co-channel and adjacent channel interference

• Handover Analysis: HSR and HFR

• Neighbor Analysis: Missing neighbors

• Call Analysis: DCR,CSSR,CSR,Call Setup time,Call hold time etc.• Layer 2 Analysis

• Layer 3 Analysis

Level Analysis

The level statistics refer to the received signal level for a mobile:• Level (Full) Distribution (between -47 and -110)• Level (Sub) Distribution (between -47 and -110)• Cumulative Level Distribution• Level Banding

RxLev Distribution

RxQual

-Quality full and Sub distribution for both hopping and non- hopping samples-Cumulative Quality Distribution-Interference

Handover Analysis

• Problem areas are automatically identified • Handover success/failure is shown on route• Position failure is located on XY graph• Cause/solution proposed for each failure• Step-by-step replay control allows every stage

of handover to be broken down for detailed analysis

• Forced Handover

Handover Stats

• Handover Distribution - The number of Inter and intra cell handovers attempted, completed and failed

• Handover Performance - Inter and intra cell success rate and the total HO success rate

• Number of Handovers per call - The number of handovers that occurred per call within the testmobile survey.

Neighbour Analysis

• The serving cells ID and full geographic location• The ID and full geographic location of the Neighbour cells that are

either missing or have not been measured• Problem areas are separately displayed on the 2D map view

Call Analysis

• Analysis of live calls, call success, signal levels and call quality can be done

• Mean and worst call levels, quality, detailed comparative summary of cells signal strengths, analysis of sites

Call Statistics

• Call Distribution - Evaluates every call and categorizes 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, Failure rate

and Release rate.• Call Setup - Time Distribution Call Timers

Call Performance

Cell Statistics

• Cell Domination• Cell poor Quality Distribution• Cell Average Quality Distribution• Cell Average Level Distribution • Cell Mean Call Holding Time• Cell average TA Distribution

Layer2 &Layer 3 Messages

Layer3 Information During Drive Test

DL RLC Throughput Vs DL RLC BLER

DL LLC Throughput (bytes/sec) vs DL RLC BLER

NEPTUNE AND PROBE

Neptune Features

• State-of- the-art PC based optimization tool delivering real time analysis capabilities

• User friendly with intuitive menu structure making it ideal for both real-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 the

substantial shortening of the optimization process.• Supports additional testmobile formats, which can be loaded and

analyzed

Test Mobile Import Facility

• TEMS Investigator• TOM Measurement System• GPRS and HSCSD, Nemo technologies• GSM log files from X-PLOR ANT units

Probe

• Has ability to perform time-based, operator based and distance based analysis

• Statistics generated show the system’ s problems as a whole rather than pin-pointing each and every problem

Features

• Ideal for both real-time and post measurement analysis• Displays a network’s Key Performance Indicators• Key Performance Indicators are combined to produce the Network

Quality and Efficiency Factor• Statistical and graphical display• Long and short term cost savings due to competitive pricing and the

substantial shortening of the optimization process• Flexible hardware option