Joint Power Control and Time Allocation for Joint Radar and Communication System in Cognitive Radio Enabled Vehicular Ad-hoc Networks

In cognitive radio networks, the secondary users perceive the spectrum and access it to data transmission when the primary users are absent. Then in the cognitive radio enabled vehicular ad-hoc networks (CR-VANETs), the secondary users and the primary users are the secondary intelligent vehicles and the primary intelligent vehicles, respectively. In this paper, we propose the joint radar and communication system in the CRVANET, making that the radar module of the secondary user perceives the whole driving enviromuent periodically and uses the spectrum to communication if no one is detected. Then we study the tradeoff problem between radar sensing and throughput of the secondary user. Numerical results and simulations prove that when the frame duration is lOms, the total power of the secondaryuseris 20W and the detection probabilityis 99.9%, the optimal radar sensing time and radar module power achieving the maximum throughput are O.07ms and 7.5W, respectively.