Realizing Multi-Gbps Vehicular Communication: Design, Implication, and Validation

This paper proposes a vehicular communication system that can achieve multi-Gbps data rate transmission for train and car applications. Employing a millimeter-wave frequency band around 25 GHz, the proposed system provides mobile backhaul connectivity for vehicle user equipments (UEs). In order to support a very high data rate with such a high carrier frequency while guaranteeing sufficient robustness against high mobility-related behaviors such as fast channel variation and unstable handover, we employ a relaying network architecture consisting of a backhaul link to a vehicle UE and an in-vehicle access link. Based on that, we provide a set of fundamental design elements including numerology, frame structure, the reference signal, multi-antenna scheme, and handover. We then validate the proposed vehicular communication system by implementing an experimental testbed consisting of baseband modem, RF front end, an array antenna units, and by performing field trials in an actual subway tunnel and urban road environments. The experimental validation results reveal that providing multi-Gbps backhaul transmission is possible and worthwhile for both train and car scenarios.