GCW: A Game Theoretic Contention Window Adjustment Approach for IEEE 802.11 WLANs

In unsupervised contention-based networks such as DCF mode of IEEE 802.11, wireless nodes compete to access the shared medium which is called random access or multiple access channel. The most important problem in such networks is the manner in which a node is selected to access the channel. In such networks, each node adjusts its channel access probability by tuning its contention window (CW) size. In case of excessive number of nodes, adjusting CW size irrespective of the number of competing nodes causes the network performance to reduce due to severe collisions. Game theory is a powerful tool for modeling, analysis and optimization of shared resources in competitive environments. In this study, the problem of channel access control is investigated in game theory framework. Specifically, based on the analytical models of DCF, a game theoretic approach, called GCW (game theoretic CW), is proposed to tune CW dynamically. Using GCW, each node can choose its CW autonomously, such that the overall network performance is improved.