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