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

The EDCA protocol was designed to enhance the functionality of the IEEE 802.11 WLAN through the introduction of different channel access parameter values for different traffic types. This enables some degree of service guarantee for traffic depending on their QoS requirements. While the improved standard has recommended values for the channel accessing parameters, it does not take into account the dynamic nature of the WLAN and for optimal performance, the contention window (CW) value should be dynamic and vary with the number of contending stations on the WLAN. In this paper, we propose a feedback based control algorithm (FCA) that outputs contention window parameter with respect to number of active nodes on the WLAN. The controller can also be tuned based on network design requirements.