The Research And Implementation Of Key Technologies Of WLAN MAC Layer Based On IEEE Std 802.11n

Although Wireless Local Area Network (WLAN) is developing rapidly, the low transmission speed prevents WLAN's further development. For more credible capability and faster transmission speed, it needs adopting the next method of wireless mobile communication. In March, 2008, IEEE approved the 3.07 draft version of 802.11n protocol. It improved 802.11 standards all-around. Aggregate frames, BA, PSMP and many other technologies are used in the MAC of the networking system, which improved the statistic frame structure, capability of MAC and the ability of networking throughput. MIMO- OFDM technology, the technology of combination of OFDM and MIMO is imported in the physical layer, has elevated the transmission speed largely. This thesis is based on the draft of IEEE802.11n 2.0 version, herein too large spending of the MAC layer is the most important factor, pivotal character in accessing devices (AP, AC) and central (AC + Fit AP) structure have been designed and achieved.The main content as follows: First, it describes component and basic service of IEEE 802.11 and defines structure of different frames, wireless LAN's model and network- ing service have been discussed; The pivotal technology such as aggregate frames, predigesting of frame structure, bespeaking time, PSMP and many effective improving throughput have been studied. Second, based on the actual networking, the achieving of pivotal technology in the MAC of WLAN's accessing devices have been designed and realized: including channel management of 802.11n, bandwidth configuration of 20/40 MHz, the speed of 802.11n and MCS management, supporting traits of 802.11n and users' mixed connecting of 802.11a/b/g, the realization of A-MSDU and A-MPDU, the realization of receiving and sending of HT Capability and HT Information. Third, through actual combination of networking, with networking operation testing software Chariot, analyzed the output of the experiment.IEEE802.11n standard has overall improved IEEE802.11 standard, not only the physical layer standard, in the same time it adopted new technology, elevated capability of MAC layer, optimized the frame structure, and increased network's throughput capability. IEEE802.11n can elevate the transmission speed to 100Mbps or more from 54Mbps, and even as fast as 600Mbps, laid the foundation for the full realization of the WLAN's fast transmission. At present, this scheme has been realized successfully in the products, and used in the business.