MAC design for WiFi infrastructure networks: a game-theoretic approach

TL;DR

This paper uses game theory to analyze and improve WiFi MAC protocols, ensuring fair resource sharing among nodes with different traffic interests through equilibrium strategies and mechanism design.

Contribution

It introduces a game-theoretic framework for WiFi MAC design, proposing strategies and mechanisms to achieve fair and efficient equilibria in shared channel access.

Findings

Efficient equilibria are achieved when stations adopt the same strategy.

Fair resource sharing is guaranteed at equilibrium.

Mechanisms can enforce desired equilibria in upload-only traffic scenarios.

Abstract

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. Assuming that each node is rational and implements a best response strategy, we show that efficient equilibria conditions can be reached when stations are interested in both uploading and downloading traffic. More interesting, these equilibria are reached when all the stations play the same strategy, thus guaranteeing a fair resource sharing. When stations are interested in upload traffic only, we also propose a mechanism design, based on an artificial dropping of layer-2 acknowledgments, to force desired equilibria. Finally, we propose and evaluate some simple DCF extensions for practically implementing our theoretical findings.