Game-Theoretic Cross-Layer Design in WLANs

In this paper, an incompletely cooperative game- theoretic MAC protocol is presented to improve the performance of WLANs. Firstly, each node estimates the current game state upon running CSMA/CA. Secondly, each node changes its equilibrium strategy by tuning its local contention parameters based on the estimated game state. Finally, the game is repeated finitely to get the optimal performance. To implement the distributed game, cross-layer design is introduced for simultaneously estimating the PHY-specific and MAC-specific game state (e.g., bit rates and the number of competing nodes), and adjusting the strategy (e.g., by tuning the minimum contention window) to the estimated game state. A simple and run-time method is provided to obtain the game state without additional CPU and bandwidth consumption. The simulation results show that the game can increase system throughput, and decrease delay, jitter and bit drop rate.