A novel reputation-based Tit-for-Tat strategy for IEEE 802.11 CSMA/CA protocol

In non-cooperative environments such as public hotspots, selfish nodes can take advantage of the mechanisms in place to obtain unfair shares of the network resources. Unfortunately, such a selfish behavior may impact the performance of the other nodes. In this paper, we address the problem of fairly sharing the IEEE 802.11 network resources in the presence of selfish nodes. Our objective is to propose a novel medium access control protocol which can fairly share the available medium among cooperative nodes but can retaliate if some selfish ones are present. We present a novel game theoretical strategy that is specifically designed to cope with the short-term unfairness of resource sharing. The proposed reputation-based Tit-for-Tat mechanism is immune to infrequent misclassification errors and motivates rational selfish nodes to cooperate under the threat of retaliation. The mechanism depends on the observation of the nodes´ behavior. If any node misbehaves, the monitoring nodes should adapt and behave selfishly. Thus, rational nodes should not have any other choice than to follow the legitimate behavior defined in the IEEE 802.11 standard in order to maximize their potential payoff.