| Multiple-input multiple-output (MIMO) and MIMO-Orthogonal Frequency Division Multiplexing (MIMO-OFDM) wireless communication system, which can provide higher capacity gain and communication quality over conventional single antenna systems, have been a hot topic in wireless communication area in recent years, while the receivers of them usually need to solve the problems of high dimensional estimation, which leads to high complexity. How to effectively suppress the co-channel interference in MIMO systems, retrieve the transmitted signal and achieve the performance gains of MIMO systems over single antenna ones with as low complexity as possible, is a very challenging task. On the purpose of pursuing good trade off between performance and complexity, taking MIMO transmission scheme the combination of MIMO and OFDM and the signal detection of them as the breakthrough point, this dissertation will focus on some meaningful aspects on MIMO systems as follows:By researching the detection algorithms of Vertical Bell Laboratories Layered Space-Time(VBLAST) transmission scheme, such as Maximum Likelihood (ML), Zero Forcing(ZF), Ordered Successive Interference Cancellation (OSIC) and so on. Because the OSIC algorithm was able to obtain the compromise between the performance and the complexity of the systems, it became to be the most competitive detection algorithm. By analyzing the simplified ML detection algorithm in STBC systems, we can obtain a useful inspiration and provide new idea for the design of high effective detection algorithm in specific MIMO system.In this paper, a few of transmission schemes were investigated, and an equivalent channel model of Group-wise Space-Time Block Code-MIMO(G-STBC MIMO) transmission scheme was modeled. Learn from the thoughts of OSIC detection algorithm which is applicated in V_BLAST systems, An new algorithm was proposed in this paper, which is applicable to the detection of G-STBC MIMO systems. At last, the theoretical analysis and simulation results show that GOSIC detection algorithm can effectively exploit the additional diversity potential of G-STBC systems over V_BLAST ones, and outperform the corresponding conventional algorithm due to adopting non-linear interference cancellation (IC) and optimal ordering.Aiming at the problem of high-performance high-rate downlink transmissions in frequency-selective fading MIMO channels, an G-STBC MIMO-OFDM Systems is presented, which exploring the advantages of combination of GOSIC detection algorithm and a detection scheme based on subcarrier grouping. the new detection scheme was proposed by combining the advantages of subcarrier correlation and antenna-grouping based MIMO-OFDM system. The OFDM subcarriers were divided into several groups and the subcarriers bound into the same group shared the same detection parameters, which were obtained at the center subcarrier of that group. This feature can significantly reduce the detection complexity. The simulation results show that compared with exhaustive detection scheme, the proposed scheme is capable of reducing large complexity with very small performance loss. |
