Finding the performance bottleneck of the IEEE802.11e EDCA mechanism on single Access Point (AP) based WLAN systems

The IEEE 802.11e Enhanced Distributed Channel Access (EDCA) is the distributed channel access mechanism introduced by an amendment to the original IEEE 802.11 standard. EDCA provides a class-based differentiated Quality of Service (QoS) to IEEE 802.11 WLANs. This paper presents a simulation study of the EDCA mechanism, considering a single Access Point (AP) based WLAN system. We used in our simulation study, the International Telecommunication Union (ITU) indoor propagation model considering the indoor or semi-indoor deployment scenarios of the WLAN systems in most real life cases. Simulation experiments show that a node accessing highest priority traffic through an AP from a high distance at high data rate not only suffers performance drops itself but also severely bottlenecks the performance of other client nodes, accessing traffics with comparatively lower priority even if those nodes are at close proximity from the AP.