Design a defense strategy against the selfish behavior of nodes using IEEE 802.11 MAC protocol

The cooperation of all nodes of an ad hoc network guarantees the optimal performance of this network. However, a node can behave selfishly at the MAC sublayer of IEEE 802.11 protocol which manages the access control to the medium. Such a selfish behavior can decrease the size of the contention windows in order to increase the priority of the transmission. The consequence of such a behavior for a node is an improvement on its throughput. This should lead to a decrease of the network bandwidth.;In this research, we design a defense strategy based on the Tit-for-Tat strategy (TFT). TFT was designed in game theory to deal with selfish behaviors. We will demonstrate why and how such a strategy aims to achieve fairness in sharing bandwidth. We will introduce variations of the TFT strategy as generous Tit-for-Tat (GTFT). The generosity factor is going to allow us to adapt ourselves to the constraints of the medium. Finally we will discuss the choice and the parameters influence of such a strategy on the behavior of the node and the entire network.;Keywords: Ad-hoc Networks, MAC, CSMA/CA, TFT, GTFT.