Reserch On PHY Security Of Wireless Networks Based On Coalition Formation Game

With the rising of the physical layer security, cooperative communication between wireless network nodes has become an important technique for improving the physical layer security of wireless transmission. Game theory, especially coalitional game, provides a very formal and structured analysis tool for solving this problem. From the viewpoint of coalition formation game, two problems are studied for the multi-node cooperative wiretap channels in this paper.First, by using the relevant knowledge of coalitional game, a multi-user cooperative communication system with relay and wiretap channel is studied. The cooperation problem of the users is formulized as a coalitional game with non-transferable utility, and a distributed algorithm for coalition formation is proposed. Finally, the coalitional structure is got and the validity of the proposed algorithm is verified by comparing the secrecy capacity of each user with the non-cooperative case. Furthermore, the self-adaption of the network’s topology is also studied. Subsequently, this paper applies the theory of the coalitional formation game with non-transferable utility above to research the security of physical layer with users performing collaborative beamforming. The simulation results prove the rationality and validity of this application.Secondly, this paper analyses a relay selection model including a transmitting node, a destination node, an eavesdropper node and a couple of intermediate nodes. In order to obtain a higher secrecy capacity, the source wants to select a plurality of nodes from the intermediate nodes to forward information. Due to each intermediate node has possibility to be selected and obtain the payment from the source, all the nodes have the potential relationship of cooperation and competition. In this paper, by using the relevant knowledge of coalition game, the relay selection problem is formulized as coalition formation problem with transferable utility. With a new definition of the comparison rule, a novel relay selection algorithm based on distributed coalition formation is proposed. The simulation results show that the performance of this distributed algorithm is obviously better than the centralized selection algorithm.