| Recently,high quality,large capacity and rapid speed have become the developing trend of future wireless communication technology.Thereby,how to provide efficient and reliable signal transmission and detection technology to achieve the above advantages is one of the studying highlights of future wireless communication systems.Iterative detection is a receiving signal processing technology based on the Soft-Input Soft-Output(SISO)method.It has been widely used in many signal processing fields such as coding and equalization,and it has obtained considerable performance gains.Therefore,this thesis aims to study the key technology of iterative detection at the receiving end about wireless communication systems.In addition,based on the Expectation Propagation(EP)algorithm,it further provides the advantages of low complexity and high performance in iterative detection.The structure of the full text is summarized as follows:The first chapter focuses on the classic transmission technology in wireless communication systems,including Interleave Division Multiple Access technology,new Spatial Modulation(SM)technology and iterative detection technology.Then this chapter discusses the current research status of related technologies.The second chapter studies the frequency domain Turbo equalization iterative technology based on system model of Single Carrier(SC)Spatial Modulation(SC-SM)and discusses its transceiver architecture,technical characteristics and traditional equalization algorithms in detail.Then,based on the sparse characteristics of Spatial Modulation,the expectation propagation algorithm in Compressive Sensing(CS)is first applied to SC-SM system.And the link simulation results demonstrate that the proposed equalization algorithm based on expectation propagation achieves a better trade-off between the error performance and the computation complexity than the traditional equalization algorithms under the multi-antenna configuration.The third chapter discusses the multi-user iterative detection technology in the Interleave Division Multiple Access system.First,the Bit Error Rate(BER)performance based on the Elementary Signal Estimator(ESE)and the new expectation propagation detection algorithm are simulated and evaluated.Subsequently,in view of the influence of Carrier Frequency Offset(CFO),a frequency offset compensation algorithm based on EP is proposed,and the link simulation results reveal that the proposed algorithm can effectively make up the performance loss caused by CFO and significantly improve the system BER performance.The fourth chapter researches the iterative detection technology based on single antenna and multi-antenna in short-wave communication system.In the first place,the joint processing procedure of mutual information between demodulation,descrambling and Turbo iterative detection in the single-antenna system is discussed;Then,a mutual information longitudinal joint detection scheme under multi-antenna distributed system model is designed,and a space-time equalization robust receiver model based on expectation propagation is proposed;Finally,the BER performance of various receiver schemes is evaluated,and the simulation results show that the proposed receiver scheme has a more improved Signal-to-Noise Ratio(SNR)about 4dB performance gains than the traditional single-antenna independent processing receiver scheme.Furthermore,compared to the current two-way decision scheme,the received SNR of the proposed receiver scheme is higher improved by about 2.5dB performacne gains,leading to a lower implementation complexity.The fifth chapter summarizes the full text,and further expands the future research work. |
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