Joint Optimal Relay Selection and Power Control for Reliable Broadcast Communication in Platoon

Vehicle platooning is an effective approach to enhance road safety, improve traffic throughput and fuel efficiency. The periodic transmission of cooperative awareness messages (CAM) can further improve platooning control performance. In particular, the CAM of the platoon leader (PL) has the greatest impact on platooning. The string stability can be achieved and inter-vehicle distance can be decreased relies on the PL's CAM (PLC). The PL manages and controls the entire platoon by broadcasting CAM. To improve the reliability of the PLC distribution in a challenging environment, we propose to jointly select an optimal relay vehicle for improved channel environment and control power to ensure communication link reliability. Two communication strategies are proposed to solve the formulated problem. First, we use a centralized method to solve the formulated problem. Then, based on the analysis result of the centralized method, we combined the sequential communication mode of the predecessor-leader following control strategy to propose a distributed scheme. The simulation results are given to demonstrate that the proposed schemes can provide reliable broadcast communication and consume the lowest transmission power.