Precoding Mimo Communications Technology Research,

Modern wireless communication systems require higher data transmission rate than ever. That promotes the research and the application of the new and sophisticated signal processing methods. Precoding is one of the signal processing methods which requires channel state information(CSI) at the transmitter. It is developed to increase the data transmission rate or decrease the BER of the wireless communication. At present, precoding has been included in IEEE 802.16e. And the 3GPP standard also uses precoding technique.Because the Multiple Input Multiple Output(MIMO) systems enable to grow linearly in transmission rate with the minimum of the number of antennas at either end, MIMO is one of the most promising techniques in B3G systems. Space Time Block Code (STBC) and Bell Laboratories Layered Space-Time(BLAST) are two main techniques which make full use of MIMO channel. The former increases the diversity gain, in order to increase the reliability of the systems. While, the latter increases the multiplexing gain to increase the data rate.How to precode depends on how to develop the MIMO systems. Precoding can be divided into STBC precoding and BLAST precoding. According to the pattern of MIMO channel decomposition, precoding also can be divided into SVD precoding and GMD precoding. At the same time, to feedback full channel knowledge to the transmitter is not realistic. Precoding based on the partial CSI is developing, especially the codebook design. This research focuses on the codebook design and give a new codebook design method for the GMD precoding.To summarize, the research includes the following aspects:In Part One, the paper intruduces the background of this topic.In Part Two, the paper introduces the MIMO channel, the MIMO capacity, STBC and BLAST.Part Three analyzes several kinds of precoding methods and mainly expatiates the SVD and GMD precoding in details.In Part Four, the research summarizes the codebook design for the limited rate feedback precoding, and presents a new codebook design method for GMD precoding. The author has proved that the codebook design for GMD precoding can be separated into two codebooks cascaded. By performing simulation on Matlab? platform, the results show that when the MIMO channel rank is 3 and the feedback bits are 5, the system performance is very well. The difference with the perfect GMD precding is less than 1dBIn Part Five, the paper briefly gives some knowledge of precoding in the multi-user MIMO systems, and puts the GMD precoding into multi-user MIMO systems.In the end, Part Six reaches the conclusion.