An analytical model for the IEEE 802.11e EDCF

The IEEE 802.11e protocol is designed to enhance the QoS capability of wireless local area networks (WLAN). In this paper, we propose a multidimensional Markov model for the 802.11e enhanced distributed coordination function (EDCF) mode and compute the maximum sustainable throughput and service delay distribution for each priority class when under heavy load. Since the QoS mechanisms and their associated parameters in IEEE 802.11e interact with each other in a complex way, it is important to model the aggregate effect of all the mechanisms. The approach we present does so and therefore provides an analytical approach to pick the parameter values associated with EDCF to meet the QoS requirements of each priority.