Research On Spatial Modulation Based Multi-antenna Scheme

With the rapid development of wireless mobile communication, the demand of people for services of high data rate and high reliability has become more and more high. In the future wireless communication systems, high data rate or high frequency efficiency is the key element to promote technical development. In MIMO (Multiple Input Multiple Output) systems, V-BLAST (Vertical Bell Labs Layered Space Time) architecture is a time-space multiplex technique, which can achieve the highest frequency efficiency of MIMO system. However it suffers severe inter channel interference. Space-time code can achieve full diversity through designing orthogonal codes to decrease the complexity of receivers. The biggest problem of space-time coding system is the limited frequency efficiency.Spatial modulation can conquer these technical problems. In spatial modulation system, antenna index is an additional source of transmitted information, and only one active antenna transmits data. Therefore this kind of system can solve the problem of inter channel interference and can improve frequency efficiency with increasing the number of transmit antennas. However, for systems with multiple antennas, the idea of spatial modulation is a kind of waste of multiple antennas in some way, which also means a potential improvement. In this paper, the principle and detection algorithm of spatial modulation are firstly introduced, then Generalised Spatial Modulation and Adaptive Spatial Modulation are illustrated and their performances are analyzed.An improved multi-antenna transmission scheme based on spatial modulation, i.e. Space-time Coded Adaptive Spatial Modulation, is proposed in this paper. On the base of Adaptive Spatial Modulation, in antenna selection unit, a combination of two antennas is selected. In this combination, symbols transmitted on the two antennas are space-time coded. The full diversity of space-time code decreases bit error rate of this system. Analysis and comparison with other schemes of performance simulation show that in the condition of same frequency efficiency and transmit power the performance of Space-time Coded Adaptive Spatial Modulation has been significantly improved compared to Adaptive Spatial Modulation, Space-time coded spatial modulation and original Spatial Modulation.