A Control Theoretic Scheme for Efficient Video Transmission over

The EDCA mechanism of the IEEE 802.11 standard has been designed to support, among others, video trac. This mechanism relies on a number of parameters whose conguration is left open by the standard. Although there are some recommended values for these parameters, they are xed independent of the WLAN conditions, which results in suboptimal performance. Following this observation, a number of approaches in the literature have been devised to set the EDCA parameters based on an estimation of the WLAN conditions. However, these previous approaches are based on heuristics and hence do not guarantee optimized performance. In this paper we propose a novel algorithm to adjust the EDCA parameters to carry video trac which, in contrast to previous approaches, is sustained on mathematical foundations that guarantee optimal performance. In particular, our approach builds upon i) an analytical model of the WLAN performance under video trac, used to derive the optimal point of operation of EDCA, and ii) a control theoretic designed mechanism which drives the WLAN to this point of operation. Via extensive simulations, we show that the proposed approach performs optimally and substantially outperforms the standard recommended conguration as well as previous adaptive proposals