Handover testing is a crucial stage in the development and deployment of wireless systems in which the cellular devices are in motion. A handover is most simply envisioned as a person driving down an interstate highway while on a cellular call and the call being long enough in duration to necessitate that it is handed over to the next cell tower in proximity to the car as the call begins to fade away from its originating tower. As applications for wireless systems grow exponentially, so, too, do the complexities of handover testing. Many of today’s handovers need to handle high speed data communications (often with IP preservation), for instance, and/or serve ultra-reliable low latency communications (URLLC).
Handover testing requires knowledge of both the instruments for mimicking and altering real-world signal profiles as well as the expertise to accurately capture and interpret the test data. Skills may be required for altering the signal strength among many paths, changing the phase delay of the signals, and otherwise accounting for a diversity of network topologies and connection scenarios. (An expert handover test engineer might be considered something of a wireless signal juggler extraordinaire.)
There are many ways handover tests can be configured using both integrated preprogrammed broad frequency band (and often costly) equipment or utilizing less complicated self-programmable devices connected to a PC via a USB or Ethernet connection. While the former method is more traditional, wireless test engineers working on applications with recurring and limited frequency bands are finding the most nimble and efficient solution to be utilizing devices they can program and manipulate through the simple graphic user interface (GUI) that is provided free with today’s USB/Ethernet programmable devices.
This Tech Brief offers wireless test engineers and technicians insight on common handover testing scenarios and challenges and introduces how they can be easily resolved with both hand-held and rack mounted programmable RF attenuators, matrices, switches, and power dividers.