Secure transmission in cooperative wireless networks: A two-level coalitional game approach

In this paper, we propose a novel hybrid beamforming and jamming strategy to secure the transmission in wireless cooperative networks. It enhances the secrecy capacity by cooperatively using distributed multi-antenna techniques to maximize the secrecy capacity, as well as nullify the information leakage at the eavesdropper and the interference at the legitimate users. The optimum intermediate relays and jammers selection is modeled as a two-level coalitional game problem. A distributed coalition formation algorithm based on merge-and-split rules is devised to solve the problem. The approach enables the intermediate nodes self-organize into independent disjoint coalitions and requires much less computational complexity. Then the optimal relaying and jamming coalitions are selected to secure transmission in a cooperative way. Extensive simulations demonstrate that the proposed coalition formation method can improve the secrecy capacity significantly compared with the existing non-collaborate relaying and jamming nodes selection scheme and random selection approach.