Nash Bargaining Game Based Subcarrier Allocation for Physical Layer Security in Orthogonal Frequency Division Multiplexing System

Most orthogonal frequency division multiplexing (OFDM) wireless communication system cooperative schemes are poor in secure transmission. Based on Nash bargaining game (NBG), this paper presents a method of OFDM system cooperative scheme restricted in physical layer security. In the model, each wireless node can act as not only a source, but also a potential relay. The sub-carrier allocation problem among selfish nodes is formulated as a two-person bargaining game to guarantee fairness. It is proved that the Nash bargaining solution (NBS) of subcarrier allocation is existence of unique Nash equilibrium. Based on evolutionary game algorithm (EGA), the subcarrier allocation scheme can reach to an optimal value and achieve an extra system secrecy rate, compared with the direct transmission secrecy rate. Simulation results indicate that the subcarrier allocation fairness is dependent on how much rate increase its partner can make to.