Performance analysis of contention-based channel access mechanisms of 802.11 DCF and 802.11e EDCA

The IEEE 802.11 legacy standard could not offer QoS support for time-critical applications. Considerable research efforts on medium access control (MAC) layer have been carried out important enhancements on improving QoS for IEEE 802.11 device implemented standard. Among them, IEEE 802.11e standard is the QoS enhanced proposed by the IEEE. The contention based channel access method called enhanced distributed channel access (EDCA) is considered as the mandatory mode for medium access control in IEEE 802.11e as distributed contention function (DFC) in IEEE 802.11. The scope of this paper is to evaluate the performances of IEEE 802.11e EDCA compared to the legacy DCF QoS support on handling multimedia applications. The performance of IEEE 802.11e MAC mechanism was evaluated through computer simulations. Performing ad-hoc and infrastructure scenarios, the study demonstrates the benefits of QoS prioritization for the IEEE 802.11e framework in terms of jitter, delay and corresponding access categories allocation.