Analysis of the EDCA access mechanism for an IEEE 802.11e-compatible wireless LAN

Wireless local area networks (WLANs) are in a period of great expansion and there is a strong need for them to support multimedia applications. The IEEE 802.11 standard defines the way WLANs work at the physical and medium access control (MAC) level. The recently-approved IEEE 802.11e amendment proposes a MAC protocol capable of offering quality of service (QoS) guarantees. This work has to do with EDCA (Enhanced Distributed Channel Access), which is one of the mechanisms introduced in IEEE 802.11e. EDCA promises to become a widely used protocol for terminals to gain access to services with QoS guarantees. It is then extremely important to assess its performance concerning the main QoS metrics, namely throughput, delay and losses under different traffic conditions, which is exactly the goal of this work. We obtain a set of equations by modeling the system using discrete-time Markov chains, and then validate these equations using simulations.