Design And Research Of Dual-Mode Generalized Spatial Modulation Scheme Based On Multi-Relay Cooperation

In 5G and B5G,people’s demand for high-speed and reliable communication is increasing.Multiple-input multiple-output(MIMO)technology is widely used because of its high spectral efficiency and stable communication quality.Spatial modulation(SM)is a new type of MIMO technology that uses the transmit antenna index and transmit modulation symbols to jointly carry transmit information.This unique transmission method reduces the complexity of the MIMO system and overcomes the problems of inter-channel interference and inter-antenna synchronization in MIMO technology.However,SM only activates a single antenna,its spectral efficiency is poor.At present,there are some improved SM solutions,which improve the spectral efficiency and system reliability of SM to a certain extent,but there is still room for improvement.In this paper,the high-efficiency SM system is studied,and two improved SM schemes are proposed,namely,dual-mode generalized spatial modulation(DGSM)scheme and joint mapping based dual-mode generalized spatial modulation(JM-DGSM)scheme.In addition,in order to deal with the channel fading and shadow effects in actual communication,the paper further combines these two improved SM schemes with cooperative communication technology,which improves the system reliability in the actual communication environment.The main research work is summarized as follows:1)The DGSM scheme is proposed.The scheme divides the transmitted bit information into three parts,which are used to select the active antenna,the combination mode and the modulation symbol respectively.In this paper,the upper bound of the symbol error ratio(SER)is deduced theoretically,and the main factors affecting the system SER performance are analyzed.The simulation results show that the theoretical results of the SER performance are in good agreement with the actual results,which proves the correctness of the theoretical deduction.In addition,through the simulation of the system SER performance,it is verified that DGSM has more excellent reliability than several existing schemes under the same antenna resource configuration and spectral efficiency conditions.2)The JM-DGSM scheme is proposed.In this scheme,the information of each part of DGSM is jointly mapped,which reduces the waste of antenna resources,so that lower order modulation can be adopted with the same spectral efficiency.In order to reflect the performance difference of different mapping coding methods,the paper analyzes the average bit error rate(ABER)of the JM-DGSM system and deduces the upper bound of the system ABER.The correctness of the theoretical deduction is verified by simulation.In order to solve the problem that the ABER of JM-DGSM is greatly affected by the coding mode,this paper designs a low complexity joint mapping coding algorithm based on channel state information,which adopts the idea of greedy algorithm and realizes global optimization through local optimization.Finally,through the performance simulation of the system ABER,it is verified that the algorithm can greatly improve the reliability of JM-DGSM.3)Finally,aiming at the channel fading and shadow effects existing in actual communication,the proposed two improved SM schemes are introduced into the multi-relay cooperative communication system.Firstly,a dual-mode generalized SM scheme system based on multi-relay cooperation is designed,and then the communication process using the amplify-and-forward protocol and the decode-and-forward protocol is introduced.Since the system involves joint mapping and coding,the ABER performance analysis of the dual-mode generalized SM scheme system based on multi-relay cooperation is given.Finally,the simulation results show that combining the improved SM scheme with the multi-relay cooperative communication system can achieve significant performance improvement.