Collision Resilient V2X Communication via Grant-Free NOMA

In vehicle-to-everything (V2X) communication, vehicles will perform the resources selection on their own, once there is no central coordination of the transmissions by the base station. If the vehicles choose to contest the same time-frequency resources, then a collision of the transmitted messages will occur. This can highly impact the reliability and latency of the vehicular link, which are crucial for safety-related applications. In this paper, we propose applying the framework of grant-free non-orthogonal multiple access (NOMA) for a collision resilient V2X communication. Grant-free NOMA allows for uncoordinated transmissions and can resolve collisions by means of specially designed transmit signatures, combined with an advanced receiver that utilizes the structure of those signatures. Our initial results suggest that such a framework has the potential to substantially enhance the system robustness to collisions, in terms of both reliability and latency.