Integrated application MAC modeling 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 WLANs. To perform cross-layer optimization realistic analytical models are necessary that arc able to accurately predict the interactions between layers, such that the parameters of the physical, MAC, transport and application layers are correctly identified. In this paper, we propose to modify existing IEEE 802.11 WLAN MAC models to explicitly consider how they impact and are impacted by the application layer in real-time video transmission systems. Specifically, we adapt existing MAC distributed coordination function (DCF) models to consider the actual arrival rates of video flow packets, as well as provide adaptive retransmission limit for video packets with different priorities. Conversely, the video application can adjust the maximum retransmission limit per packet and the video rate based on realistic 802.11 MAC models rather than on simplistic two-state Markov models for packet-losses. Consequently, these integrated MAC-application layer models can be used to assist the cross-layer optimization for real-time wireless transmission by realistically predicting the interactions between layers.