When buying a new car, high-quality cellular and Internet access have become major considerations for customers. No matter how good the car, poor wireless communications are no longer acceptable. The introduction of connected and driverless cars has also increased the need for strong wireless performance.

University of Bristol researchers, in collaboration with Jaguar Land Rover, have developed a Virtual Drive Testing (VDT) method that is reliable, cost-effective and a repeatable alternative to physical drive tests.

Saving cost, time

Cellular connectivity is usually verified by a comprehensive set of real-world drive tests in a wide variety of urban and rural environments. The process requires the construction of a physical prototype that is costly, time consuming and lacks the scientific rigour and the ability to repeat the tests.

Based on a dual-antenna LTE-Advanced Vehicle-to-Infrastructure (V2I) urban scenario, the research compared real-world and virtual drive tests. The Bristol engineering team have developed a radio performance test process based on 3D ray-traced channel models, theoretic or measured antenna patterns, RF channel emulation and hardware-in-the-loop radio measurements.

3D ray-traced channel models were used to predict the timed-related radio paths between a cellular base station and the test vehicle. Measured vehicular antenna patterns were then applied to the predicted channel data using a spatial and polarimetric convolution process. The resulting channels were streamed into a Keysight PropSim F8 channel emulator, which was programmed to communicate with the multi-channel cellular base station emulator and a Samsung S5 mobile handset.

The VDT process was shown to be reliable and repeatable. The accuracy of the emulated throughput agreed well with real-world measurements performed by Jaguar Land Rover in central Bristol.

"VDT allows vehicular antenna designs to be evaluated even before a physical prototype has been constructed. This new process allows us to rapidly compare and contrast a wide range of on-vehicle antenna solutions. This ensures we are able to rapidly converge on the very best solution," said Professor Andrew Nix, Dean of Engineering and Head of the Communication Systems and Networks (CSN) group at the University of Bristol.