Performance analysis of IEEE 802.11e enhanced distributed channel access

In this research article, we have proposed an analytical model for the performance analysis of the enhanced distributed channel access (EDCA) protocol of IEEE 802.11e wireless local area networks standard, using four-dimensional Markov chain. The contemporary EDCA models support only a small subset of EDCA features with limited accuracy. Our model accurately covers all salient features of standard EDCA, like multiple numbers of simultaneously active access categories (AC) per station, internal collision handling, post-back-off after successful transmission and frame-discarding after maximum retransmission limit. The proposed model has also implemented pre-back-off carrier sensing mechanism and back-off counter freezing with deferred states in both the cases. It has incorporated different carrier sensing and back-off parameters for each active AC for access category wise service differentiation. We have computed the saturation throughput and frame access delay of each access category for both RTS/CTS and basic modes. Analytical model is validated by simulation.