A modified cooperation stimulation mechanism based on Game Theory in ad hoc networks

In an ad hoc network, due to the absence of centralized infrastructure, the performance of the networks is seriously affected by selfish nodes refusing to forward packets for others. Because of the packet collisions and channel interference, it´s not always possible to devise correctly if a given node forwarded a packet for another node or not. In this paper a repeated-game model of nodes cooperation is established based on the Game Theory. And we propose a cooperation stimulation mechanism using the Restorative Trigger strategy. The main idea of the strategy is to mitigate performance loss after a node has been mistakenly perceived as selfish and reestablish cooperation quickly. The parameter settings of the mechanism satisfying the Nash equilibrium are discussed. Theoretical analysis and simulation results indicate that our scheme can detect and punish the selfishness with certain tolerance by adjusting the parameters of the model. Thus the cooperation between nodes can be effectively stimulated.