SD-EDCF Algorithm Based On QoS Research With Traffic Category

Along with the appearance of more and more video and voice services and the development of the wireless communication technology, the discussion becomes a hot spot for people pursuing the enjoyment of any service at any time, anywhere, in any way; and in order to satisfy the requirement, the multimedia real time services, which were once realized in wired and fixed network, are developed towards the wireless and mobile solutions.As a rising communication technology, the wireless network communication is playing a more and more important role in daily life. in recent years, with the popularization of WLAN, especially the Wireless Local Area Networks technology, the users are hoping more that the multimedia services can be applied on this stage; but the protocol design of the WLAN was aimed for the data service at the first, not for the real time services. So, the problem of how. to promote and optimize the performance of the Wireless LAN becomes quite important; although the IEEE802.11e work group has made some supplement for the real time service to guarantee the QoS, the discussion with this topic is still under the way.This paper describes the characteristic of WLAN at first, then, summarizes the key technology and development foreground of the WLAN, following by the analysis of the existing WLAN MAC layer scheme and parameters related which can influence the performance of the WLAN.After the background knowledge introduction, we provide a deep analysis and discussion of the WLAN QoS implementation methodology, focus on the CW algorithm improvement and the realization of QoS in the 802.11x protocol family. Then we present a new way of QoS based on the 802.11e, which can provide better performance under saturation network conditions with high level of congestions, and is proved to be effective from the simulation results of OPNET software.At the end, we give a summary and suggestion for future researches.