Evaluation of Contention-Based EDCA for IEEE 802.11e Wireless LAN 429 Evaluation of Contention-Based EDCA for IEEE 802.11e Wireless LAN

802.11b The legacy IEEE 801.11 doesn’t support QoS streams with priorities. It since causes some QoS demanding applications such as VoIP, Video streaming to be limited in its usefulness. Enhancements have been made to the MAC layer by the new 802.11e standard to support prioritized and parameterized QoS. The work of this paper is to simulate the new scheme and modify the existing OPNET WLAN MAC model to satisfy the 802.11e standard. The modification includes adding four access category queues, AP beacon with EDCA parameters, AC queue switcher and an internal collision handler to evaluate the contention-based channel access mechanism, called enhanced distributed coordination access (EDCA) in the current 802.11e. The performance of those new schemes has been compared with DCF of the 802.11 standard via simulation results. It clearly indicates the IEEE 802.11 EDCA function can effectively provide QoS differentiation.