Research On Pre-Coding In Multiple-user Multiple-Input Multiple-Output Systems

Multiple-input and multiple-output, MIMO communication system that is unique in its large capacity and high reliability in high-speed wireless communication occupies an important position. Pre-coding is a pre-equalization technique that suppresses the interference between users at the transmitter. Because MIMO system pre-coding can reduce the complexity of the receiving end and effective to prevent the error diffusion, so the field in the current communication, improve the transmission rate and the BER performance of the system is the research hotspot in MIMO pre-coding.In this paper, the linear and non-linear pre-coding technology for the multi-user MIMO systems are investigated. The main work is as follows:1Do deeply into understanding of MIMO systems related knowledge. Research on the modeling and analysis of multi-user MIMO systems.2For multi-user MIMO linear pre-coding system a few basic algorithm were studied, analyzed the advantages and disadvantages and carried out a systematic analysis of simulation and application. Including the zero forcing (ZF) linear pre-coding, the block diagonalization (BD) linear pre-coding, the minimum mean square error (MMSE) linear pre-coding and the signal leakage ratio (SLR) linear pre-coding. The paper proves the minimum mean square error (MMSE) performance optimal linear pre-coding, and it is the optimal algorithm. Aiming at the drawbacks of the method and putting forward the improvement methods.3For multi-user MIMO system linear pre-coding TH (Tomlinson-Harashima) pre-coding studied, proposed based on the quantized channel state information (CSI) for TH pre-coding scheme to achieve an average sum rate. And proposed the nonlinear TH Pre-coding can achieve much better performance than that of linear zero-forcing pre-coding for both perfect CSI and quantized CSI cases.