An Improved Application MAC Model for Cross-Layer Optimized Wireless Video

Cross-layer optimization has been recently proposed for improving the performance of real-time video transmission over 802.11 WLAN. In this paper, an improved IEEE 802.11 WLAN analytical model under unsaturated traffic conditions was proposed. It adapts Distributed Coordination Function (DCF) models to handle all the states. Two special states were added for this model, one is the idle state, which means the MAC queue is empty, and the other is D state, which means if the medium is sensed to be unoccupied for a time interval greater than the DIFS, then the station proceeds with the packet transmission. The improved model can be used to assist the cross-layer optimization for real-time wireless transmission though realistically predicting the interactions between layers.