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 ○ Status Information○ Error reports○ Layer 2 messages○ 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 throughputUL/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