Feedback control algorithm for optimal throughput in IEEE 802.11e EDCA networks

Abstract

The minimum contention window ( $ {\rm CW}_{\min } $ ) value of the EDCA protocol gives priority access to the different categories of traffic on the WLAN and also affects the rate of collision and delays experienced on the WLAN. In the IEEE 802.11e standard, the values for the $ {\rm CW}_{\min } $ parameter are recommended values and should be adapted to WLAN conditions for optimal performance of the network but these recommended values are generally used as the de facto values for contention on the WLAN. This is due to the difficulty of assessing current conditions on the WLAN in real time due to the dynamic nature of the WLAN. In this paper, we propose a dynamic feedback based control algorithm (FCA) that assesses the WLAN and outputs contention window value with respect to number of active nodes on the WLAN. The controller can also be tuned based on network design requirements.

Keywords

• EDCA
• contention window
• feedback control