Research on physical layer security in D2D enabled cellular networks with an active eavesdropper

D2D communication, as a key technology of the 5G mobile communication system, draws a lot of attentions for its ability to enhance energy efficiency and spectrum efficiency of cellular systems. Even the interference that it brings can be regarded as “friendly” when there is a passive eavesdropper in systems, since it can improve the physical layer security of cellular users. But if there is an active eavesdropper in systems, it will affect the secure and robust communication performance. So in this paper, in order to improve robustness and security of D2D enabled cellular networks, considering there exists an attacker who has two attack modes: passively eavesdropping or actively jamming, the secrecy achievable rate and transmission rate of legitimate user under different attacked scenario are enhanced by the assistance of the selected D2D pair using joint friendly jamming and cooperative relaying method. The interaction between the legitimate user and the attacker is formulated as a non-zero non-cooperative game, and the existence of the mixture strategy is analyzed. The MSNE (mixture strategy Nash equilibrium) is derived via the algorithm based on fictitious play. Simulation results show that the proposed algorithm outperforms the classical nearest neighbor algorithm, and the strategy joint considering two collaborative ways of the selected D2D pair works better than the strategy that only considering it to be a cooperative relay or a friendly jammer.