Evaluation of the Random-LOS Measurement System for Vehicular Communication Applications

Licentiatavhandling, 2017

The automotive industry is progressively closing on the Telecom industry as wireless data connection and transmission become more and more important for vehicles. In both future and present cars, the safety and infotainment systems depend on reliable wireless data transmission. This is especially the case when autonomous cars will reach the market. With this development, it becomes important to test and to verify that the required wireless communication is achieved. Today, there are no standardized methods of how to perform this testing. Proposed methods are all based on scaled up mobile phone testing. However, it is not problem-free to scale these methods to larger objects, such as vehicles, since it can become both expensive and complicated. To overcome these issues, a hypothesis has been introduced stating that “If a wireless device is tested with good performance in both pure-LOS and RIMP environments, it will also perform well in real-life environments and situations, in a statistical sense”. In this hypothesis, the Rich Isotropic Multipath (RIMP) and the Random Line-of- Sight (Random-LOS) are introduced as the two edge environments for testing. In this thesis, the focus is on one of these edge environments, i.e., the Random-LOS environment. This thesis studies how the Random-LOS environment can be realized for performance testing of wireless communication for vehicles. The investigation has been divided in two main parts. The first is to study how the Random-LOS testing environment can be achieved. Simulations and measurements have been performed for three different chamber antennas, a single antenna element, a horizontal uniform linear array and a uniform planar array. The antennas have been compared in terms of amplitude (or rather power) and phase variations within a test zone in front of the chamber antenna. The second part investigates how actual system performance measurements can be performed with a Random-LOS measurement setup. These measurements have been conducted with simplified setups, testing the concept and validate the throughput performance when comparing different vehicular antennas.