On Selfish Behavior in Wireless Sensor Networks: A Game Theoretic Case Study

In this paper, we study the selfish behavior in wireless sensor networks and apply a game theory method to address this problem in a CSMA/CA protocol. More specifically, we formulate the Media Access Control (MAC) layer activity in sensor networks as an optimization problem in terms of the random accessing problem. Then we propose a distributed algorithm for the system to reach the Nash Equilibrium (NE). We have de-fined a Contention Window Select Game (CWSG) in which each sensor selects its own contention window to control the access probability. This approach can improve the average performance, compared to a random strategy with each sensor selecting its own window independently. We prove the unique existence of NE in the CWSG, and propose a penalizing mechan-ism based on repeated game to prevent the non-cooperative selfish behavior of decreasing the contention window without per-mission.