Research On Concatenated System Of SM-MIMO And Nonbinary LDPC

Both of the multiple-in-multiple-out technology and the excellent channel coding technology are powerful and important for high-speed and high-quality wireless communication transmittion. Spatial modulation (SM) technology is a new multiple-antenna technology which gets rid of the inner-antenna interference and provides nice spectral efficiency and energy effiency. The nonbinary LDPC codes, as one of the best channel codes, have excellent error correcting performance. This paper focuses on the research of the concatenated system of SM-MIMO and nonbinary LDPC code. The construction of the nonbianry LDPC codes, the soft SM-MIMO detection and the iterative detection-decoding technology are studied in the paper.Firstly, the fundamental knowledge of the nonbinary LDPC codes and the multiple-antenna technology is introduced. For the nonbinary LDPC codes, some basic concepts including definition, parity-check matrix and Tanner graph are presented. As to the multiple-antenna technology, the conventional MIMO technology is introduced at first, taking STBC and V-BLAST for example to introduce the tranimit diversity and multiplexing techonology. After that, the fundamental principle of SM-MIMO is presented and a comparison of different SM-MIMO schemes with the same data rates is made.Then, the construction of nonbinary LDPC codes is studied in detail, mainly on the construction of binary mother matrix and the replacement of nonbinary elements. Several important factors that affect the performance of nonbinary LDPC codes are analysised. The binary mother matrix is constructed via PEG algorithm and its improved algorithm RandPEG. As to the replacement of nonbinary elements, the conventional full rank condition is improved by adding a new metric X to provide further guidance on selecting better nonbinary elements from all the elements that fulfill the conventional FRC. Based on the X-FRC, a greedy search algorithm and an iterative search algorithm are proposed to select the nonbinary elements efficiently.Next, the soft detection-decoding technologies of the concatenated system of SM-MIMO and nonbinary LDPC code are studied. For the single-user system, the research is mainly about the soft detecting algorithm with low complexity and high performance. We proposed single-quadrant ML detecting algorithm and its improved algorithm. Besides, the application of MMSE algorithm in SM-MIMO system is also investigated. For the multiple-user system, the MMSE detector and CHEMP detector are studied. And both of them are combined with the iterative detection-decoding technology to improve the performance of the system.Finally, the paper makes a conclusion of the research and gives the possible directions of the future research.