Survey of Admission Control Algorithms in IEEE 802.11e Wireless LANs

The provision of quality of service (QoS) in wireless network becomes very important. IEEE 802.11e standard was introduced to enhance the media access control (MAC) layer operations to provide the QoS experienced by traffic flows. But only IEEE 802.11e can not guarantee network congestion avoidance and traffic QoS especially to multimedia traffics. So, an efficient admission control scheme is necessary to transmit multimedia traffic in high efficiency and quality. At present many admission control schemes have been proposed, in this paper we overall summarize the purpose, basic components, and classifications of admission control. And then present a survey of admission control in IEEE 802.11e EDCA and HCCA,these admission control schemes are discussed according to different categories: Measurement-based, model-based, hybrid schemes of EDCA and physical-rate and contention-window-based of HCCA in IEEE 802.11e WLANs. Finally we will compare these schemes to get the advantages and disadvantages and point out the remaining challenges which are useful for us to study the admission control under heterogeneous networks and make admission control schemes accurate and simple.