Coalition formation game of dual-identity nodes for improving PHY security of wireless networks

In wireless communication, coalitional game theory has been a promising approach for analyzing cooperative networks to improve the physical layer security. In this paper, we propose a new model in which each user acts as a dual-identity node, a data source or a friendly jammer, and then formulize the cooperation problem based on the proposed model as a coalitional game. Furthermore, we propose a novel distributed algorithm based on “merge-and-split rules”, based on which the dual-identity nodes can mutually effect and cooperate into disjoint independent coalitions which can maximize the total secrecy capacity of all the users with a fixed power constraint. Finally, the coalitional structure is got and the validity of the proposed algorithm is verified by the simulation results as improving the secrecy capacity of each user comparing with the non-cooperative case. In addition, the self-adaption of the network's topology is also studied.