Research On The Improved Signal Vector Based Detection In SM System

As one of the key technologies of wireless communication systems, Multiple Input Multiple Output(MIMO) is known for its high speed and spectral efficiency. The spatial multiplexing can reach the highest spectral efficiency, but inter-channel interference is serious; the space diversity using the orthogonal code can reduce the complexity of the receiver and obtain diversity gains, but has low spectrum efficiency. A new MIMO transmit technology, spatial modulation(SM), chooses the active transmit antenna indices based on input bits. As only one transmitting antenna is actived at one time slot, the inter-channel interference(ICI) is efficiently avoided. Also, the design of SM receiver can be simplified. Thus, SM becomes one of the research hotspots in the MIMO technology.This paper focuses on the research of detection algorithms for SM system and aims at exploring a detection algorithm with low complexity and almost the optimal performance. This paper studies several classic spatial modulation detection algorithms and focuses on the signal vector based detection(SVD) algorithm. Considering the limitations of SVD algorithm, an improved signal vector based detection algorithm is proposed. We introduce the idea of candidate antennas to improve the BER performance of SM system,and optimize the demodulation algorithm to reduce its complexity. It has been verified by the simulation that the BER performance of the improved algorithm is close to the optimal performance, and the complexity is much lower than the optimal detection. Besides, by changing the number of candidate antennas, the improved algorithm can be considered as the product of a compromise between the performance and complexity.Despite the introduction of spatial dimension, transmission efficiency of SM system is lower compared with spatial multiplexing system. In the last part, this paper studies on the generalized spatial modulation(GSM) system, and applies the improved algorithm in it. The simulation results show that under the premise of using the same number of the transmitting antenna, the transmission efficiency of GSM system is higher, and the improved algorithm in GSM system still has good BER performance.