Opportunistic Spectrum Access for CR-VANETs: A Game-Theoretic Approach

In this paper, we investigate the opportunistic spectrum access for cognitive radio vehicular ad hoc networks. The probability distribution of the channel availability is first derived through a finite-state continuous-time Markov chain, jointly considering the mobility of vehicles and the spatial distribution and temporal channel usage pattern of primary transmitters. Utilizing the channel availability statistics, we propose a game-theoretic spectrum access scheme for vehicles to opportunistically access licensed channels in a distributed manner. In particular, the spectrum access process is modeled as a noncooperative congestion game. The existence of the Nash equilibrium (NE) is proved, and its efficiency is analyzed when employing the uniform medium access control protocol and slotted ALOHA, respectively. Furthermore, a spectrum access algorithm is devised to achieve a pure NE with high efficiency and fairness. Simulation results validate our analysis and demonstrate that the proposed spectrum access scheme can achieve higher utility and fairness, compared with a random access scheme.