Research On Antenna Selection And Detection Algorithm In Generalized Spatial Modulation System

As one of the key technologies of 5G mobile cellular networks,Massive MIMO technology has become a research hot topic in the field of wireless communications in recent years.Spatial Modulation(SM)and Generalized Spatial Modulation(GSM)techniques utilize the spatial information of Massive MIMO to transmit signals implicitly.It can not only effectively overcome inter-channel interference,but also reduce antenna synchronization requirements.Since the signal is transmitted invisibly,the information transmission rate can be increased,which offsets the spectral efficiency reduction caused by the idle antenna.At the same time,due to the small number of effective RF links,the implementation cost and complexity of the system can be reduced.Spatial modulation and generalized spatial modulation are considered to be powerful candidates for Massive MIMO systems.This paper takes GSM system as the research object,and focuses on the receiver detection algorithm and antenna combination selection algorithm of GSM system to improve the system performance.The main work is listed as follows:1.In the classical GSM system,independent information is transmitted by different active antenna.Compared with the extremely complexity of the maximum likelihood detection algorithm,the OB-MMSE detection algorithm has the low complexity.But the antenna ordering effect is available only in some special situation.To solve the above problems,a detection algorithm based on zero forcing and partial maximum likelihood is proposed in this paper.Compared with OB-MMSE algorithm,the algorithm has better antenna sorting effect and better bit error performance,especially in high-order modulation.Moreover,the idea of serial interference cancellation is added to the algorithm to improve the accuracy of constellation symbol detection and the bit error performance.2.For the GSM system in which the active antenna transmits same information at one slot,a low complexity detection algorithm based on signal vector and MMSE is proposed.The algorithm sort the antenna combination in terms of the signal vector angle,and then apply MMSE criterion to estimate the antenna combinations according to the sorting result,and judge whether to terminate the detection according to the preset threshold.This algorithm makes use of the characteristics of antenna transmitting the same information and the threshold setting to achieve a trade-off between BER performance and computational complexity.3.Since that the GSM performance is deteriorating gradually in correlated channel,this paper proposes an incremental antenna combination selection algorithm based on norm and correlation,which takes advantage of the redundancy of antenna combination in GSM system.The algorithm optimizes the active antenna combinations set by selecting the transmit antennas combination with weaker correlation.The simulation results illustrate that the proposed algorithm can significantly improve the BER performance of the system under Rayleigh fading correlation channel.