A Rate-Adaptive MAC for IEEE 802.11 Networks

Rate adaptation in multi-rate capable IEEE 802.11x stations is extremely challenging. Previous approaches for rate adaptation mainly focused on the factors related to the wireless medium. However, applications´ demands and timing constraints of the underlying protocols were not considered. The solution proposed in this paper tackles these shortcomings with a novel approach by performing rate adaptation according to the changing channel conditions, application preferences and timing constraints of the underlying protocols. The proposed rate adaptation is based on a loss differentiation mechanism which identifies the real cause of channel variations and takes an appropriate action thereafter. The design provides flexibility of tuning various parameters according to application type and offers minimal complexity. The simulation results assert considerable improvements over previous solutions in terms of the algorithm response to application requirements and dynamic adjustment with variation in underlying protocol performance.