Bayesian Coalitional Game in Physical Layer Security

Cooperative communication has been recently investigated as an attractive way to improve the physical layer security of wireless network. However, in practical situation, the node's behavior in the coalition is either cooperative or not due to the environment the mobile node located. Wireless network nodes do not have an exact and perfect knowledge of the cooperative behavior of the potential cooperators in coalition formation. In order to form the stable coalitional structure under behavior uncertainty of nodes, we propose the Bayesian Coalitional Games using partition model based on possible worlds (i.e. environments), which nodes enter into contracts (i.e. agreements) with one another to deal with the uncertain payoffs. We obtain the Bayesian core which is the Nash-stable and fair coalitional structure. A belief update mechanism to the nodes with cooperative behavior uncertainty is used to calculate the probability of each possible world. We also present a discrete-time Markov chain model to investigate the stability of the coalitional structure. Preliminary experimental evidence demonstrates the effectiveness of our approach.