Joint Beacon Power and Rate Control for Vehicular Ad Hoc Networks

In vehicle to vehicle communications, periodic broadcast of beacons allows awareness of vehicles in a cooperative manner. In this paper, a joint beacon rate and power control protocol based on game theory is presented to combat channel congestion that is used for transmission of beacons. The existence, uniqueness and stability of the Nash Equilibrium (NE) as the key concept of the game are proved mathematically. In order to find the equilibrium point in a distributed manner, an algorithm is devised and its stability and convergence has been validated in a simulation environment. This algorithm converges to the NE from any initial rate and power. The proposed protocol has per vehicle parameters where each vehicle can control its share of the bandwidth according to its dynamics or safety application requirements while the whole bandwidth usage is controlled. This paper reports on utilizing the rate and power control protocol and presents some early results obtained from a representative simulation environment for VANET.