A cross layer rate adaptation solution for IEEE 802.11 networks

Optimizing the performance of wireless networks for emerging network applications is a highly challenging issue. Cross layer solutions offer promising possibilities of joint optimization across the protocol suite. This paper proposes a cross layer framework for rate adaptation in 802.11 x networks. Previous approaches for rate adaptation mainly focused on the factors related to the wireless medium. However, the 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 fate 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 the previous solutions in terms of the algorithm response to application requirements and dynamic adjustment with variation in underlying protocol performance. (C) 2008 Elsevier B.V. All rights reserved.