Research And DSP Implementation Of Superposition Coding In The Spatial Modulation System

With the continuous development of technology,the fifth generation communication system(5G)needs to meet a variety of terminal devices accessing simultaneously and various service requirements,at the same time,to balance the spectrum efficiency(SE)and energy efficiency(EE)of system,finally,to achieve true green communication.There are many problems in traditional MIMO system,such as inter channel interference and multi antenna synchronization.Spatial modulation(SM)is a novel scheme,which transmits information by a kind of mapping relation between the inputting bits and the transmitting antenna's index,and it effectively balances the SE and EE of system.In this thesis,we mainly study the multi antenna transmission scheme of SM,aiming at the defects of the single layer constellation modulation in system,and considering the balance of receiver's BER performance and computational complexity,finally,we put forward the corresponding optimization and design scheme.The main research contents and innovations are as follows:1.Based on the linear coding structure of Superposition Coded Modulation(SCM)technology,it is combined with the constellation modulation of the SM system.And we design a Superposition Coded Modulation-Spatial modulation(SCM-SM)system.The number of bits used for constellation modulation is divided into several layers to be independently coded and modulated.For the hierarchical structure,this thesis presents the successive interference cancellation(SIC)signal detection,and the scheme can obtain the BER performance of approximate maximum likelihood(ML)in a low transmission rate system.2.In high speed transmission SCM-SM system,the BER performance does not meet the requirements for the SIC detection scheme,and the main reason is that the first layer of the active antenna's index is demodulated incorrectly.For better BER performance,introducing the idea of iteration,the iterative layered detection(ILD)scheme is proposed in this thesis,which is layer by layer demodulation wtih iterating the combination of candidate symbol in the first layer.Simulation results show,when the transmission rate is 7bpcu and 9bpcu,compared with maximum likelihood(ML),the computation complexity is reduced by 50% and 68.8%,and the performance is approximately ML.3.Furthermore,this thesis analyzes and studies generalized spatial modulation(GSM)scheme.The SCM scheme is applied to the constellation modulation of each active antenna,and we design the SCM of generalized spatial modulation(SCM-GSM)system.Finally,the ILD scheme is applied to the receiver,which can effectively balance the BER performance and complexity of system.4.Based on the existing signal processing platform,the ILD scheme in the SCM-SM system and SCM-GSM system are implemented with DSP,and the detection scheme is comprehensively evaluated by the actual system BER performance,hardware memory resources and operation efficiency.