Non-Cooperative Beacon Rate and Awareness Control for VANETs

In vehicular ad hoc networks (VANETs), vehicles broadcast their status information in beacons periodically to make the surrounding vehicles aware of their presence. To maximize the level of awareness, a congestion control mechanism is necessary to avoid loss of beacons due to collision in dense traffic environments. In addition to congestion control, it is desirable that vehicles share network bandwidth in a manner proportional to their dynamics or safety application requirements. Current congestion control mechanisms have a number of issues including control information overheads, fairness, and awareness. In this paper, a beacon rate and awareness control mechanism based on non-cooperative game theory called non-cooperative beacon rate and awareness control (NORAC), is proposed. The existence and uniqueness of the Nash equilibrium of the game is proved mathematically and an algorithm is proposed to find the equilibrium point in a distributed manner. The proposed algorithm is used to assign a beacon rate to every vehicle proportional to its requirements, while ensuring fairness between vehicles with the same requirement. NORAC is compared with the two other known congestion control mechanisms. The simulation results show the efficiency and stability of the proposed NORAC algorithm in several high-density traffic scenarios. The results indicate its advantages in terms of fairness and congestion and awareness control over the other two algorithms, while not requiring excessive information to be included in beacons.