| In order to realize low power consumption and high performance design of Space-Time Shift Keying(STSK)solution in the next generation wireless communication system,this paper facilitates the optimization of STSK system based on Genetic Algorithm(GA),and also designs a STSK system for next generation wireless communication combining STSK and Reconfigurable Intelligent Surface(RIS)technology.The specific research contents are as follows:This paper analyzes the related technologies of RIS and STSK in detail.Among them,for the Dispersion Matrix set(DMs)optimization of the STSK system,the random search algorithm is introduced.Then the characteristics of the STSK system and the performance advantages compared with the Spatial Modulation(SM)system are analyzed through simulations.In addition,two RIS systems,RIS-assisted communication transmission and RIS-assisted index modulation transmission,are introduced.The simulation results show that RIS has great flexibility and performance advantages in combination over other modulation techniques.In order to reduce the computational complexity of three-Dimensional(3D)STSK(3D STSK)system optimization,an improved GA is proposed to assist the joint optimization of DMs and 3D constellation.During the optimization process,on the one hand,the symmetry of the 3D constellation is used to reduce the computational complexity of the fitness value(coding gain);on the other hand,an adaptive mutation probability is designed for the 3D constellation,which can realize the adaptive search of the 3D constellation.The simulation results show that,compared with the traditional random search algorithm,the improved GA can reduce the computational complexity by about 2000 times without any performance loss.In order to solve the problem of hardware cost and power consumption caused by the combination of STSK scheme and other communication technologies,based on the concept of RIS-assisted communication transmission,a RIS-assisted STSK(RISSTSK)system is proposed to realize STSK scheme in sixth Generation(6G)wireless communication system with low-power design.On the one hand,in the proposed RISSTSK system,the incident signal is reflected by the RIS at the relay end,and the cosine similarity theorem algorithm is used to optimize the reflection phase shift at the RIS,and the RIS-STSK system is deduced by the semi-analytical probability method in which the average bit error probability verifies the correctness of the simulation.On the other hand,in order to improve the performance gain of the RIS-STSK system,the optimization is designed to improve the GA-assisted RIS reflection phase shift,and through the improved evolution and selection operations,a better Bit Error Ratio(BER)can be obtained.The simulation results show that the RIS-STSK system can significantly enhance the performance gain of the STSK scheme at a very low hardware cost.In the traditional STSK scheme,the Dispersion Matrix(DM)performance is limited by power.To improve the spectral efficiency of the STSK scheme,a High-Rate Reflection STSK(HR-RSTSK)system is designed based on the concept of RISassisted index modulation transmission.On the one hand,the 3D constellation is used to improve the BER performance of the system,and additional phases are designed based on the 3D constellation to improve the spectral efficiency of the system.At the same time,the Reflection-DM(RDM)is constructed through the reflection phase shift at the RIS,which makes the RDM get rid of the power limitation of the traditional DM,and deduces the average bit error probability of the HR-RSTSK system to verify the correctness of the simulation.On the other hand,an improved GA joint 3D constellation-assisted optimization of additional phases and Reflection-DMs(Reflection-DMs,RDMs)is proposed to obtain additional phases and RDMs with better BER performance through improved evolution operations.The simulation results show that the proposed HR-RSTSK system not only improves the spectral efficiency and BER performance of the STSK scheme,but also gets rid of the power limitation of traditional DM,which also reduces the antenna cost of the transmitter greatly. |
