Social Tie Based Cooperative Jamming for Physical Layer Security

In this letter, we investigate the cooperative jamming decision problem among multiple jammers for physical layer security. We introduce the social tie concept to model the cooperative jammer´s willingness to cooperate. We first formulate the problem as a social tie based cooperative jamming game. We establish the existence of a pure Nash equilibrium (NE) and then devise an algorithm to compute the desired NE which can achieve the minimum secrecy outage probability among all the NEs. Moreover, we derive an upper bound on the gap between the secrecy outage probability achieved at the best NE and the minimum secrecy outage probability achieved with all jammers participating. Numerical results validate our theoretical analysis.