Prioritization of Maneuver Coordination Messages and the Impact of Decentralized Congestion Control

Vehicle-to-everything (V2X) communication can enable connected and automated vehicles (CAVs) to drive cooperatively by coordinating their maneuvers. Envisioned as a future Day 3+ V2X application, CAVs can broadcast Maneuver Coordination Messages (MCMs) as part of a Maneuver Coordination Service (MCS) to exchange the necessary data. In order to prevent congestion and ensure fair use of the communication channel by the increasing number of V2X services, a Decen-tralized Congestion Control (DCC) mechanism with packet rate control has been developed and standardized by the European Telecommunications Standards Institute (ETSI). In this paper, a prioritization of MCMs is proposed based on the necessity of the maneuver and the operation mode of the MCS. Several application and network related metrics are used to analyze the impact of the DCC on the MCS with and without prioritization. A challenging scenario with a high number of transmitting vehicles is simulated, congesting the communication channel with only MCMs and with the standardized Cooperative Awareness Messages (CAMs). Evaluations are performed with DCC at the access and facilities layers. The results demonstrate the benefits of MCM prioritization and discuss the impact and issues of DCC mechanisms in the context of MCS.