Improving Resource Allocation for beyond 5G V2X Sidelink Connectivity

Cooperative automated driving (CAD) applications are expected to heavily rely on low-latency and highly reliable communications among vehicles to exchange status and kinematics parameters, planned trajectory/manoeuvers, etc. The fifth generation (5G) New Radio (NR) vehicle-to-everything (V2X) communication technology currently under specification by the Third Generation Partnership Project (3GPP) supports direct interactions over the so-called sidelink interface. Sidelink transmissions leverage orthogonal resources either allocated in a centralized manner (Mode 1) or autonomously selected by vehicles (Mode 2). Nonetheless the enhancements conceived when passing from Long Term Evolution (LTE) to 5G, the legacy solutions are still far from adequately supporting the challenging CAD demands. This is especially true under highly congested scenarios and with traffic patterns departing from the vanilla periodical generation of basic awareness messages. In this work we deeply investigate the performance of the sidelink autonomous resource allocation schemes under a variety of message generation patterns, by identifying their strengths and weaknesses, under different vehicle density settings, and provide helpful guidelines for the design of future solutions.