Research On Detection Techniques For MIMO Systems

To satisfy the demands of high data rates in 4G wireless communications, it is necessary to adopt high order modulation in MIMO-OFDM techniques,Which make the complexity of MIMO detection techniques with good performance largen sharply. In this case,the research of MIMO receiver with high performance and reduced complexity is especially important.In this work, various typical detection algorithms with hard decoder and several improved algorithms in term of complexity or performance for MIMO-OFDM are studied first, and then hierarchical modulation based sphere detection algorithm or QRM-MLD is presented for MIMO systems,especially for MIMO systems which adapt high order modulation. Compared with the original SD or QRM-MLD,the proposed algorithm shows lower complexity but the same performance.Finally, to reduce the detection complexity of receiver, introduction of preequalization is given, and then an new method about reducing the average feedback of codebook and optimization of codebook is shown when transmitter adapt the preequalization based codecook.