MAC Design for WiFi Infrastructure Networks: A Game-Theoretic Approach

In WiFi networks, mobile nodes compete for accessing a shared channel by means of a random access protocol called Distributed Coordination Function (DCF). Although this protocol is in principle fair, since all the stations have the same probability to transmit on the channel, it has been shown that unfair behaviors may emerge in actual networking scenarios because of non-standard configurations of the nodes. Due to the proliferation of open source drivers and programmable cards, enabling an easy customization of the channel access policies, we propose a game-theoretic analysis of random access schemes. We show that even when stations are selfish, efficient equilibria conditions can be reached when they are interested in both uploading and downloading traffic. We explore the utilization of the Access Point as an arbitrator for improving the global network performance. Finally, we propose and evaluate some simple DCF extensions for practically implementing our theoretical findings.