5G Network Testing Equipment: What is drive test in RF engineering & why are RF drive test tools needed?

Whenever a new RF design is configured on the 3G/4G/5G network, RF engineers should evaluate this with RF drive test tools to check the network performance. It can be done through few ways such as KPI (Key Performance Indicator) analysis, or prediction tools and signal interference. But, ‘Drive Test’ is the one which has been very effective and efficient in giving performance data and optimising the network. We have often heard of a drive test which is usually offered to prospects looking to buying a car or any type of vehicle to check its roadworthiness. So, how is a drive test different for the telcos and why is it needed to perform testing with 4G/5G network testing equipment and tools?

Drive test is nothing, but an RF test that is performed in mobile networks with RF drive test tools for any technology (2G, 3G, 4G, 5G) and data is collected while moving on the vehicle. It has other variations which include a walk test where the engineer is assigned to walk on the targeted location to collect data. Such kind of test has gained popularity in the telecom space and comprises of two phases: data collection and analysis.

While conducting KPI analysis, mobile network operators (MNOs) can recognize issues such as call drops, failure of handover/handoff, etc. However, drive tests give a better insight into the cellular network performance by identifying areas with excellent/low/no coverage, interference, assessing network changes and multiple other parameters.

When can be drive tests scheduled?

Nothing as specific, drive test can be conducted at different times using RF drive test tools – whether it is a day or night depending on the requirement. Operators can know about the current network condition especially with respect to the loading aspect of it when a drive test is performed during the day. On the other hand, a drive test at night is generally tested on transmitters so that a large base of users remains unaffected. For example, development and integration of new sites involves such system design and drive test is performed at night in this case whereas, for performance analysis and maintenance, daytime drive test is preferred by operators.

The value gained from RF Drive Testing

When Call Details Record (CDR) is provided to operators they only know about the phone connected to the cell tower at a particular point of time. The technician does not have the radio frequency engineering data. Conducting drive test, the technician can have:

  • Tower areas where the signal strength is stronger than others and take actions on the low signal strength sectors.
  • Hot spot areas are identified where cell tower coverage is created in multiple spots allowing people to get connected to the cell tower even if they are located far from it.
  • Identification of areas with no connectivity.
  • Nearby wooded regions, water bodies, large or small buildings, or topography may affect signal coverage and can be assessed using drive test.

Types of RF drive tests

Performing drive tests, operators achieve user experience KPIs in real-time and compare user QoE on the cellular network. Operators perform 4G/5G network testing with 4G/5G network testing equipment and tools that help them in collecting network measurements from various aspects in their locations of interest.

RF drive testing can be classified as given below:

  • Single site verification (SSV) or Single Site Drive Test – SSV testing is all about testing on a single site, usually a new site ready to be commercialised to users. RF engineers conduct this test either by drive testing or walk testing around the location.
  • Cluster Drive Test or Multiple Site Verification (MSV) – In this type of drive test, a group of cells is evaluated. It is performed in active mode when service is being provided to consumers allowing technicians to inspect interference between two cells and whether handover is carried or not.
  • Operator Benchmarking Drive Test – Such drive test is used to compare different MNOs in terms of network KPIs like throughputs, call drops, latency, etc, on 3G/4G/5G networks. With this testing, operators can recognise their strengths and take this opportunity to create new offerings based on them and attract consumers.

Conclusion

Operators should evaluate networks regularly for optimising network performance and provide better Quality of Experience (QoE) to users. Drive testing has been commonly used and is an efficient technique to collect data and process it to get deeper insights into the 3G/4G/5G networks. The analysis made through the collection of a huge amount of data from various locations gives a clear idea of the network and makes significant changes to further enhance the quality. Thus, it can be said that the RF drive test plays a critical role in radio frequency engineering enabling RF engineers to take decisions on several areas. These aspects include planning, optimisation and maintaining the entire network system with an aim to upgrade network capacity, quality and coverage on a large geographical area.

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