| Multiple input multiple output(MIMO) technique which providing higher system capacity and reliability of wireless communication transmission by equipment with mutiple antennas at the transmitter and receiver of systems, has becoming an important research topic in field of wireless communications. However, there are many limitationsin the existing MIMO transmission technique, such as structural complexity. Recently, a low-complex and low-cost new MIMO transmission technology- spatial modulation(SM) technology has been proposed. In SM, only one antenna is active at each time slot, i.e., only one antenna is used to transmit symbols, so it is possible to avoid synchronization and symbol interference between the antennas effectively, and the spectral efficiency of the system can be guaranteed. On the one hand SM technology can simplify the architecture and reduce the cost of to MIMO achievement, on the other hand it can also meet varied link configuration requirements of future communication systems. In addition, the technology also applies to the asymmetric channel multi-antenna system which has transmit antennas much greater than receive antennas.Firstly, the SM system bit error rate(BER) performance optimization method were studied, including antenna selection and a novel bit symbol mapping method, and reviews the antenna selection in MIMO system model and several typical antenna selection algorithm. Then we discuss the antenna selection for SM especially for large-scale SM systems, propose a transmit antenna selection algorithm and an improved low-complexity transmit antenna selection method further. Secondly, from the perspective of the characteristics of the received constellation, propose a new hybrid bit symbol mapping method for SM systems and confirme the effectiveness of the proposed algorithm from both theoretical analysis and simulation results. Simulation results also show the BER performance and computational complexity of the proposed method reach a good compromise.Secondly, the technology of spatial modulation system optimization of antenna resources were studied, and an improved SM ransmission scheme is poposed, which can still guarantee the spectrum efficiency of system in the case of the number of transmit antennas decreased and being not a power of 2. On the basis of the above, we propose a novel space-time block coding(STBC) aided SM transmission scheme, which is based on the improved SM transmission scheme mentioned previously. It uses the antennas saved by the improved SM transmission scheme to STBC, which maintaining the superiority of system meanwhile offering extra diversity gain. Thus, the BER performance of system is further enhanced. Finally, based on the expansion of SM technology-generalized spatial modulation(GSM) technology, popose an improved transmission scheme using discarded antenna combinations to further improve the system transmission efficiency.Finally, According to the current research and accumulation, the development direction and prospect of the space modulation system in the future communication system are discussed. |
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