A Stackelberg security game with cooperative jamming over a multiuser OFDMA network

In this paper we investigate a cooperative jamming (CJ) strategy based Stackelberg security game to improve physical layer security over multiuser OFDMA networks. Each source node tries to deliver messages to its intended destination node securely in the presence of a passive eavesdropper. Fortunately, these node pairs can resort to a friendly jammer to enhance their communication. But the jamming service is not free and the friendly jammer charges each pair for some cost. Obviously there is a tradeoff between the friendly jammer and the source-destination pairs. Consequently, a two-level Stackelberg game model is proposed, where the friendly jammer plays the seller and the source-destination pairs are the buyers. We analyze the Stackelberg Equilibrium from two sides respectively and prove the existence and uniqueness of the Stackelberg Equilibrium. Correspondingly, we also develop a distributed iterative power allocation algorithm to reach the Stackelberg Equilibrium point. Numerical Results demonstrate that the system sum secrecy rate is really improved and the physical layer security performance is effectively meliorated.