Research On IEEE802.11AJ Standard And Mu-MIMO Technology For Ultra-High Rate Millimeter Wlan

With the situation of centralized communication sevice and rare frequency band on 2.4/5GHz bands, millimeter-wave wireless communication technologies have attracted great interests for unused very wide bandwidth. A lot of researches have been done on this field from academia and industry. With the demand for high-speed communication, IEEE committee had adopted the advice from China, which is about founding IEEE802.11aj task group in order to develop a new version of the WLAN standard for millimeter wave band of China especially.As the new standard of WLAN series, IEEE802.11aj standard focuses on the physical layer transmittion and MAC layer access technology. IEEE802.11aj standard supports two kinds of physical layer, which are single-carrier physical layer and orthogonal frequency division multiplexing physical layer. SC physical layer could achieve lower power consumption with low complexity. However, OFDM physical layer is more robust against frequency selective fading. What’s more, it is the first time that IEEE802.11aj standard bring the single-carrier MIMO system into the WLAN. This paper focused on the transmittion technologies on OFDM physical layer.IEEE802.11aj standard supports the multi-user MIMO technology, which could simultaneously transmit data to more than one user and greatly improve physical layer transmission rate of Gbit/s. The key of multi-user MIMO technology is multi-user precoding in order to eliminate the interference between users. With the remarkable increase of bandwidth, the amounts of the channel state information for multi-user precoding also increase greatly. It is important to reduce the feedback overhead in order to optimize the performance of the system. This paper researched on the multi-user precoding scheme based on singular matrix V with limited channel information feedback.In this paper, the main work are as follows:1. This paper focused on IEEE802.11aj indoor wireless channel model and frame structure, of which the signal field is the point. The procedure of the baseband processing is also present. This paper also made research on some common single-user MIMO technologies including space-time coding and beamforming. Channel information feedback mechanism and MAC layer protocol are also present.2. This paper proposed a new scheme of cyclic shift diversity for IEEE 802.11aj standard. The scheme can achieve good performance without additional effort at the receiver. In addition, this paper made an analysis on the simulation result aginst space-time coding.3. This paper made research on multi-user precoding scheme based on singular matrix V with limited channel information feedback. With the channel property of IEEE802.11aj, this paper made research on the quantification of the angles in the Givens transform, which could reduce the feedback overhead of the system.4. This paper made research on the disadvantage of the traditional singular value decomposition and proposed a new sheme for the system with 2x2 structure. In addition, a more effective sheme is present for systems with any structure, which show good performance against the traditional scheme.