Performance Analysis of IEEE 802.11e EDCA in Non-saturation Condition

We focus on performance analysis of IEEE 802.11e EDCA in non-saturation condition. There have not been many analytic works in non-saturation condition due to mainly analytic complexity of models. However, non-saturation is valid in most real WLAN network. In this paper, we deal with the non-saturation case that the flow is not generated during which the previous flow is in service and flow size is geometrically distributed. This case occurs when a user wants to transmit files in a WLAN area. Our approach is to model stochastic behavior of one station as a discrete time Markov chain by substantially revising and extending the analytical model developed by Bianchi for the performance analysis of DCF in saturation condition. We obtain four performance measures: system throughput, packet average delay, packet loss probability and flow service completion time. Our results can be used for admission control to find optimal number of stations with some constraints on these measures. We present the numerical results for this analysis.