The Research On MIMO Channel Estimate And Precoding Performance

With increasing degrees of spatial freedom and multi-user diversity in multi-user multiple inputs multiple outputs (MU-MIMO) system, MU-MIMO system presents more advantages than single input single output (SISO) wireless system. In order to taking advantage of this freedom, many different schemes and algorithms, which could be classified as diversity gain and multiplexing gain, are proposed. While diversity is a scheme to enhance the reliability of communication system, multiplexing is a way to improve effectiveness of the communication system. This thesis focuses on how to improve effectiveness of the communication system by utilizing the precodingThe performance of precoding is depended on two aspects. First, how many information of channel could be known at the transmitter. Second, which method could be utilized at the transmitter? In single user MIMO system, both issues are developed very well. However, in multiple user MIMO system case, due to the annoying multiple user interference, the multiple user channel estimate and the precoding discussion are still two open issues. The precoidng performance analysis in estimate channel is beyond discussion either. In this thesis, we focus on multiple user channel estimate scheme and multiple user precoding scheme at the assumption that channel state information is known at the transmitter. In addition, we analyse the estimate channel system performance by numerical simulation. The main contribution of this dissertation could be summarized as follows:1. A novel multiple user TDMA channel estimate scheme which based on single user channel estimate is presented. The analytic results of the system performance based on minimum mean square error is presented by theortic analysis. The numerical simulation results show that our results are correct.2. An elegant proof of the optimal multi-user receiver architecture which based on single user MIMO syetem is listed which leads to receiver filter’s architecture.3. Based on the SLNR and MMSE receiver, An modified iterative algorithm is proposed in full duplex multiple user wireless MIMO system.4. The system performance between estimate channel and perfect channel are compared by throughout and bit error rate. Finally, we summarized several future research topics about multi-user MIMO system.