Spatial correlation of C-V2X antennas measured in the virtual road simulation and test area

Abstract

Modern automobiles comprise more and more radio systems and sensors, e.g. communication systems for LTE, systems based on the IEEE 802.11p standard, or radar sensors. Vehicle-to-vehicle and vehicle-to-infrastructure (vehicle-to-X) communications will play an important role to reduce accidents and also to improve traffic flow. Mobile ad-hoc as well as cellular communications via base stations might be established in order to connect traffic participants. Due to the tremendous amount of coexisting radio systems and users, vehicle-to-X systems need to be tested extensively for reliability and interoperability in various traffic situations and for different radio channel conditions. In order to minimize expensive and time-consuming test drives, current research focuses on testing automotive wireless systems under reproducible laboratory conditions, by emulating realistic propagation channels in virtual electromagnetic environments over-the-air. This paper proposes an experimental approach to emulate spatial channel properties for a MIMO setup with two LTE receive antennas for cellular vehicle-to-X applications. In view of the multipath propagation, the spatial correlation of received signals is the figure-of-merit, especially for MIMO transmission schemes. A concept for the measurement of spatial correlation is proposed, based on the transmission parameters between any pair of transmit and receive antennas. Measurements are performed in the virtual road simulation and test area of the Thuringian Center of Innovation in Mobility in the frequency range from 1700 MHz to 2700 MHz. The measured data are compared to numerical computations and partially good agreement is found.