Research On Key Technology Of EDCA In Next Generation Wireless LAN

With the rapid popularization of intelligent wireless terminals and real-time services emerging, how to ensure the quality of delay-sensitive services becomes the key to the development of WLAN. Traditional WLAN standards aim to improve the throughput and the fair access mechanism based on CSMA/CA of MAC layer leads to the intensified conflict in dense users' scenario. The launch of next generation WLAN standard 802.11 ax project means that future research will focus on how to improve average cell throughput and provide better experiences for users. The enhanced distributed channel access(EDCA) provides an effective solution to ensure the quality of service(Qo S) and IEEE802.11 ax standard working group have proposed to apply EDCA technology to the next generation of WLAN.This paper is supported by state key science and technology project ” The research of key technology of the next WLAN generation on standardization and prototype system development”, which synchronizes with the international standard IEEE 802.11 ax standardization process. The project goal is to make China stand in the next generation of WLAN standards with independent intellectual property rights and core competitiveness, and lead the progress of the international standards.The research work and innovative contributions of this paper can be summarized as follows:For the existing key problems of multiple access protocol in WLAN MAC layer, this paper analyzes the EDCA mechanism for guaranteeing service quality, and studies the effects of low rate users on cell performance. On the basis of existing EDCA theoretical analysis model, an improved three dimensional Markov chain analysis model is constructed in this paper, considering the protocol process and various parameters of channel competition. This model can be used to analyze the influences of AIFS parameters and competition window on throughput and delay. Simulation results verify the Qo S guarantee provided by Qo S parameters in this model, and the theoretical analysis results serve as theoretical basis and guidance for the application of EDCA mechanism in next generation WLAN.With the advantage of EDCA mechanism, a self-organized EDCA scheme limiting the access of low rate users is put forward in this paper. When multiple stations in a cell transfer data in WLAN, there exist low rate users due to network interference and different path loss. The scheme is able to maintain high level of cell performance by configuring different priority parameters according to adaptive network conditions, effectively guaranteeing good experience for users. The proposed scheme can improve average area throughput and average latency in the scenario where low-rate stations exist. The performance and advantage of the scheme are demonstrated through simulation. In terms of practical application of the scheme, the detailed procedures based on EDK software of MAC protocol are designed in order to implement the scheme. The performance and feasibility of the solution are experimentally verified based on warp platform.