How do I set up drive test tools for analyzing coverage gaps and dropped-call rates in a wireless network?

To set up drive test tools for analyzing coverage gaps and dropped-call rates in a wireless network, you want a workflow that captures radio measurements, location, serving/candidate cell behavior, and call/session events in a way that can be mapped geographically and correlated with the network.

1) Define the objective and KPIs

Before installing anything, decide what you need to measure:

• Coverage gaps
  • RSRP/RSRQ/SINR for LTE/5G
  • RSSI/EC/No (for legacy systems)
  • Pilot/RSCP/EcNo for UMTS
  • Signal strength thresholds by technology
• Dropped-call rate
  • Call setup success/failure
  • Call drops during voice/VoLTE/VoNR sessions
  • Handover failure rate
  • RRC/NAS/session drops and reasons

Also define:

• Network tech: 2G/3G/4G/5G
• Voice type: CS voice, VoLTE, VoNR, OTT test calls
• Route type: highways, urban, indoor, suburban
• Test conditions: busy hour vs off-peak, speed, direction, repeatability

2) Choose the right drive test platform

A complete drive test setup usually includes:

Hardware

• Test handset/modem(s) supporting the target bands and technologies
• Measurement receiver/scanner for passive RF scanning
• GPS/GNSS antenna or integrated GPS
• Laptop/tablet to run the software
• Vehicle power inverter / DC supply
• Optional:
  • External antennas
  • PDA/tablet for notes
  • Two or more test devices for simultaneous multi-carrier / multi-technology testing

Software

Common drive test software platforms:

• TEMS Investigation / TEMS Pocket
• Nemo Outdoor
• NQDI / Atoll + measurement modules
• Genex Probe / Actix / Spider / other vendor tools
• Post-processing tools:
  • Map-based analysis
  • KPI dashboards
  • Layer/neighbor analysis tools

The software should support:

• Live logging
• Device control
• Scripted call testing
• Event logging
• Export to common formats (CSV, XML, SQL, MDT-compatible formats)

3) Prepare the test devices

Set up one or more devices with:

• Correct SIMs and service profiles
• Enabled test modes if required by the vendor
• Locked or configurable:
  • RAT preference (LTE/NR/UMTS)
  • Band selection
  • Carrier aggregation options
  • VoLTE/VoNR settings
• Correct APN / IMS configuration if testing data or VoIP
• Disable:
  • Auto-updates
  • Battery optimization
  • Unnecessary apps
• Ensure phones are factory reset or cleanly configured for repeatability

For scanner-based setups:

• Load band plans and technology configurations
• Calibrate frequency lists and scan profiles

4) Install and calibrate GPS/location

Coverage gap analysis depends on accurate geo-tagging.

• Use a high-quality GPS receiver or integrated GNSS with good antenna placement
• Verify:
  • Time synchronization
  • Latitude/longitude accuracy
  • Altitude if needed
  • Heading and speed
• Set logging interval appropriately:
  • 1 second is common
  • Faster if supported and needed
• Make sure the test vehicle has a stable GPS fix before starting logging

5) Configure logging and events

Set the logging profile to capture:

Radio measurements

• Serving cell ID
• Neighbor cells
• RSRP/RSRQ/SINR or tech-specific equivalents
• Band/channel/frequency
• Handover events
• Timing advance / CQI / BLER if available

Call/session events

• Call origination
• Call connected
• Call release
• Drop reason
• Handover during call
• Data session attach/throughput if relevant

Network and device context

• Device state
• IMS registration status
• RRC/NAS signaling causes
• Error codes and timestamps

Best practice

Log with:

• Timestamped events
• Continuous RF samples
• Event markers
• Route/sector annotations
• Voice recording if analyzing audio impairments

6) Create test scripts for repeatability

Use scripted sequences so every test is consistent.

Examples:

• Idle in a weak-coverage area for 30 seconds
• Place a voice call for 2–3 minutes
• Move through handover zones
• Trigger uplink/downlink data tests
• Repeat on the same route in both directions

For dropped-call analysis:

• Keep call duration long enough to encounter mobility problems
• Include handover-heavy areas, tunnels, cell-edge zones, and dense urban streets

For coverage analysis:

• Drive routes that include:
  • Cell edges
  • Known complaint areas
  • Indoor-to-outdoor transitions
  • Topography changes
  • Tunnels/underpasses

7) Perform the drive test

During the drive:

• Start GPS lock and logging before moving
• Keep handset placement consistent
• Maintain the same device orientation when possible
• Follow the route at a consistent speed
• Record:
  • Weather
  • Traffic
  • Any incidents or route deviations
  • Manual notes about visible outages or indoor areas

If possible, run:

• A passive scanner continuously
• An active call test in parallel
• A data throughput test separately or on a second device

8) Analyze coverage gaps

Look for:

• Low RSRP/RSCP areas
• Poor SINR/RSRQ regions
• Sudden loss of serving cell
• Excessive reselection
• Strong signal but poor quality, which may indicate interference or congestion

Useful maps:

• Heatmaps of signal strength
• Handover maps
• Serving cell dominance maps
• Drop clusters by geographic location
• Layer-specific coverage plots

Typical coverage gap indicators:

• Repeated “no service”
• Frequent fallback to lower RAT
• Long periods below threshold
• Edge areas with unstable serving cell selection

9) Analyze dropped calls

For dropped calls, correlate:

• Time of drop
• Location
• Serving cell
• Neighbor availability
• Handover history
• Signal quality prior to drop
• Release cause codes

Common root causes:

• Coverage holes
• Poor uplink coverage
• Missing neighbors
• Handover failures
• Overshooting cells
• Interference
• Congestion
• Core network/IMS issues
• Device-specific problems

A good process is:

1. Identify all drop events
2. Group them by location and serving cell
3. Compare RF conditions before the drop
4. Check if the drop aligns with handover or mobility events
5. Compare against network counters and alarms

10) Correlate with network data

Drive test alone is not enough. Correlate with:

• OSS/KPI counters
• Neighbor lists
• Site configurations
• RF planning data
• Outage/alarm logs
• MDT or crowdsourced data if available

This helps distinguish:

• True coverage problems
• Planning issues
• Parameter issues
• Transient outages

11) Export and report

Export logs into a format that supports:

• Map overlays
• KPI trend charts
• Route replay
• Event timelines

Your report should include:

• Route map
• Date/time
• Device and software version
• KPIs
• Drop call summary
• Coverage hole locations
• Screenshots/heatmaps
• Recommendations

12) Practical tips

• Test multiple times to confirm repeatability
• Use the same phone model when comparing sites
• Separate coverage issues from capacity issues
• Avoid mixing too many variables in one test
• For 5G, test both NSA and SA if both are deployed
• Validate with stationary tests in suspected weak areas

Recommended basic setup

If you want a simple starting point:

• 1 laptop with drive test software
• 1 smartphone supporting target bands
• 1 GPS receiver
• 1 external scanner if budget allows
• Vehicle power adapter
• A predefined route with known problem areas
• Scripted voice calls + logging at 1-second intervals

If you want, I can also give you:

1. a sample drive test checklist,
2. a tool comparison (TEMS vs Nemo vs others), or
3. a step-by-step setup for LTE/5G specifically.