Research On QoS-guaranteed Medium Access ControlMechanism For WLAN

Personal data communication with the development of powerful portable data terminal and the extensive use of multimedia terminals, wireless local area network to ensure quality of service needs to become urgent problems. Network diversity requirements for conventional IEEE802.11 protocol can not meet, for IEEE802.11 Panel with service differentiation IEEE802.11e draft agreement.This paper introduces the research background paper outlining the research background of wireless LAN, wireless LAN applications; Secondly, we introduce the conception of transmission zone based on the Markov chain, which takes into account almost all the important MAC parameters, and use it to analysis the EDCF mechanism, give the throughput expressions of every portfolio.Since the parameter configuration of EDCF in IEEE 802.11 is performed in static mode, the change in the amount of service load is not considered in the setup processes of each station. A D-EDCF mechanism is proposed to modulate the minimum Contention Window based on how busy the channel is. At last, the simulation results prove that this mechanism utilizes the channel more efficiently and improves the QoS of Data Service when net is light.