Usually, the terrain and clutter data available from the maps are not perfect
Purposes of CW drive testing
▪ Characterization of propagation and fading effects
▪ Optimize and adjust the prediction model (Propagation model tuning)
▪ Coverage evaluation of candidate sites
▪ Assessing Interference & overlaps of candidate sites
Tx Antenna Selection
- For model tuning, Omni-directional Antenna is highly recommended
- For coverage evaluation of candidate sites, it depends on the BTS Antenna type whether Omni-directional or
Sectorized Antennas - Don’t test drive in the shadow regions
Site Selection
- For propagation model tuning, test site and its height should be distributed within the clutter under study
- For candidate site verification, the actual site configuration should be used
Frequency Selection
- A clear frequency/channel (free of interference or traffic) should be used for CW testing
- Verification is required using spectrum analyzer or suitable receiver
Drive Routes
- Using maps, plan your measurement collection routes prior to CW testing & eliminate duplicate route
- Significant amount of data should be collected for each clutter category
Transmitter Setup
- Tx antenna should be free of any nearby obstacles
- For sites with existing antennas, precaution is required to avoid interference or inter-modulation issues
- For model tuning, maximum Tx power of the CW transmitter is used
- For candidate site verification, the actual BTS power is used
- Interference precaution is required for sites with existing antennas
Receiver Setup
- Receivers with high sample rates are required to comply with Lambda Lee Criteria (36 – 50 samples per 40
Lambda) - Neighbor cells should be measured as well to analyze coverage overlap & interference existence
- Check the RSSI level close to Tx station to make sure the setup is working properly prior to the test
- GPS receiver is needed to provide location information of each measured sample
Drive Test
- Create & initiate a measurement session using data collection SW
- Maintain the car speed according to the configured sample rate
- Follow the drive routes as close as possible
- Use markers to indicate special locations/hot spots or potential interference
Measurement Reporting
CW Drive Testing Process
- The exported file should contain Latitude, Longitude and RSS levels
- Data averaging may be needed with some data collection SW tools
- Compatibility to different file formats of RF planning tools (Mapinfo, Asset, Planet,..etc)is required for successful data
importing. - Graphical plots may be exported for acceptance purpose