Bayesian Game Model for Congestion Control on Periodic Safety Beaconing in the IEEE 802.11p/WAVE Vehicular Networks

Abstract

Vehicular Ad-hoc Networks (VANETs) facilitate the broadcasting of status information among nearly vehicles and between vehicles. IEEE 802.11p is an approved amendment to the IEEE 802.11 standard to add Wireless Access in Vehicular Environments (WAVE), a wireless vehicular network system. In the IEEE 802.11p/WAVE vehicle network environment, the strict periodic beacon broadcasting of safety messages requires status advertisement to assist drivers in maintaining safety. The beacon broadcasting is required for real-time communication, and for avoiding the degradation of communication channels in high vehicular density situations. However, a periodic safety beacon in the IEEE 802.11p/WAVE standard can only transmit packets on a single channel using the MAC protocol. In high vehicular density situations, the channel becomes overloaded, thereby increasing the probability of beacon collision, and hence reducing the influx of successfully received beacons, which increases the delay. Many studies have indicated that appropriate congestion control algorithms are essential to provide efficient operation of a network. In this thesis, to avoid beacon congestion, I proposed Bayesian game theoretic models of wireless MAC where each transmitter makes individual decisions regarding their power level or transmission probability. I have evaluated the equilibrium transmission strategies of both the selfish and the cooperative user. In such a game-theoretic study, the central question is whether Bayesian Nash Equilibrium (BNE) exists, and if so, whether the network operates efficiently at the equilibrium point. I proved that there exist BNE point of both cooperative and non-cooperative game and validated the feasibility of the proposed approach using simulation. The performance of the proposed scheme is illustrated with the help of simulation results. The simulation results showed that the proposed scheme could achieve a higher delivery ratio of road safety messages and small overhead in dense network.