Mechanism Of IEEE802.11e EDCA And Its Improved Algorithms Research

With the rapid development of wireless communication, more and more mobileterminal needs a convenient way to access the Internet, so the wireless local areanetwork (WLAN) came into being. WLAN is a computer local area network on thebasis of the wired LAN, and developed in order to solve the difficulty in wiring andmobile. WLAN from the introduction to the present, the corresponding standardconstantly updated, such as the IEEE802.11series wireless protocol, HomeRF,Bluetooth, and LiperLAN wireless LAN based on the IEEE802.11standard has beenrapid development in recent years and a wide range of applications, IEEE802.11cannot be business to provide good QoS support its enhanced protocol IEEE802.lleproposed just to make up for this deficiency.The IEEE802.11e protocol in the MAC layer to the introduction of the hybridcoordination function (HCF), comprising two access mechanisms, i.e. EnhancedDistributed Channel Access (EDCA) and Hybrid Coordination Function ControlledChannel Access (HCCA) two channel access method. EDCA is similar to the802.11DCF contained in CSMA/CA method-based contention access mechanism, on the basisof DCF increased the difference between priority services, to ensure that the differentpriority service QoS, but when the network size, especially when the network load islarger, the IEEE802.11e protocol there is the problem of irrational resourceconsumption, this research is necessary, the content of the research has importantresearch value and practical significance.Firstly, the subject of academic value and practical significance, as well asdomestic and foreign research status, and then analyze the IEEE802.11DistributedCoordination Function (DCF) and Point Coordination Function (PCF), focusing onresearch and summarized the IEEE802.11e protocol the technical characteristics andcore principles; then create a Markov model, and derive the expression EDCA networkthroughput and network delay; last for the IEEE802.11e protocol channel resourcesoccupied by the problem of irrational, proposed an optimization improved EDCAmechanism-MTS-EDCA mechanism and verified by network simulation of the effectof the mechanism, the results show that the MTS-EDCA greatly improve the channelresource consumption unreasonable.