Drive testing

Drive testing is a method of measuring and assessing the coverage, capacity and Quality of Service (QoS) of a mobile radio network.

The technique consists of using a motor vehicle containing mobile radio network air interface measurement equipment that can detect and record a wide variety of the physical and virtual parameters of mobile cellular service in a given geographical area.

By measuring what a wireless network subscriber would experience in any specific area, wireless carriers can make directed changes to their networks that provide better coverage and service to their customers.

Drive testing requires a mobile vehicle outfitted with drive testing measurement equipment. The equipment are usually highly specialized electronic devices that interface to OEM mobile handsets. This ensures measurements are realistic and comparable to actual user experiences.

Data collected during drive testing

Drive test equipment typically collects data relating to the network itself, services running on the network such as voice or data services, radio frequency scanner information and GPS information to provide location logging.

The data set collected during drive testing field measurements can include information such as:

• Signal intensity
• Signal quality
• Interference
• Dropped calls
• Blocked calls
• Anomalous events
• Call statistics
• Service level statistics
• Quality of Service information
• Handover information
• Neighboring cell information
• GPS location co-ordinates

Types of drive testing

Drive testing can broadly be categorized into three distinct topics:

• Network benchmarking.
• Optimization and troubleshooting
• Service quality monitoring.

The result produced by drive testing for each of these purposes is different.

Network benchmarking

For benchmarking, sophisticated multi-channel tools such as Focus Infocom's DMTS and XGMA, DingLi Communications' Pilot Fleet, Ascom's Symphony or Rohde & Schwarz-SwissQual's Diversity Benchmarker are used to measure several network technologies and service types simultaneously to very high accuracy, to provide directly comparable information regarding competitive strengths and weaknesses. Results from benchmarking activities,such a comparative coverage analysis or comparative data network speed analysis, are frequently used in marketing campaigns. Drive testing to gather network bench-marking data is the only way mobile network operators can collect accurate competitive data on the true level of their own and their competitors technical performance and quality levels.

Optimization and troubleshooting

Optimization and troubleshooting information is more typically used to aid in finding specific problems during the rollout phases of new networks or to observe specific problems reported by consumers during the operational phase of the network lifecycle. In this mode drive testing data is used to diagnose the root cause of specific, typically localized, network issues such as dropped calls or missing neighbour cell assignments.

Service quality monitoring

Service quality monitoring typically involves making test calls across the network to a fixed test unit to assess the relative quality of various services using Mean opinion score (MOS). Quality monitoring focuses on the end user experience of the service, and allows mobile network operators to react to what effectively subjective quality degradations by investigating the technical cause of the problem in time-correlated data collected during the drive test. Service quality monitoring is typically carried out in an automated fashion, using devices that run largely without human intervention carried in vehicles that regularly ply typical drive testing routes such as garbage collection vehicles, taxis or buses.

Drive testing can be conducted at any time on a live network and very rarely will there be any network intrusion.

References

1 - Drive testing LTE, available from: <http://www.viavisolutions.com/sites/default/files/technical-library-files/drivetesting_lte_wp_nsd_tm_ae_0.pdf>