Service Differentiation in Wireless Networks: Adaptive Ad Hoc Qs Versus IEEE 802.11e

IEEE 802.11e standard was proposed to provide quality of service (QoS) support in wireless local area networks (WLANs). Currently, the number of WLAN cards which support this standard is limited and on the other hand many users already have WLAN cards. We proposed a MAC-independent service differentiation mechanism which is called ad hoc Qs. Furthermore, we enhanced its operations by making it adaptive to the number of active stations and the requested service. In this paper, we compare the performance of 802.11e and adaptive ad hoc Qs in terms of service differentiation in wireless networks. The simulation results show that the adaptive ad hoc Qs surpasses 802.11e in some features: Firstly, adaptive ad hoc Qs is implemented just by software upgrade in contrast to IEEE 802.11e which needs hardware upgrade. Secondly, By increasing the amount of High priority traffics, the low priority traffics will suffer from starvation when 802.11e standard is used for service differentiation. Adaptive ad hoc Qs protects the Low priority traffics from starvation while the amount of High priority traffics is increasing. In addition, adaptive ad hoc Qs provides higher channel utilization in multi-hop wireless ad-hoc network compare to 802.11e.