A Game-Theoretic Model for Medium Access Control

In this paper, a game-theoretic model for contention based medium access control (contention control) is proposed. We define a general game-theoretic model, called random access game, to capture the distributed nature of contention control and the interaction among wireless nodes with contention-based medium access. We study the design of random access games, characterize their equilibria, study their dynamics, and propose distributed algorithms to achieve the equilibria. This provides a unique perspective to understand existing MAC protocols and a general framework to guide the design of new ones to improve the system performance. As examples, a series of utility functions is proposed for games achieving the maximum throughput in a network of homogeneous nodes. The convergence of different variants (e.g., asynchronous and stochastic algorithms) of different dynamic algorithms such as gradient play are obtained. An equilibrium selection algorithm is also proposed to guarantee that the dynamic algorithms can actually achieve the desired operating point. Simulation results show that game model based protocols can achieve superior performance over the standard IEEE 802.11 DCF, and comparable performance as existing protocols with the best performance in literature.