Research And Simulation Of High Efficient Pilot Transmission And Detection Technology

With the continuous development of mobile communication technology,the fifth generation mobile communication system(5G)has been commercialized on a large scale,in which waveform modulation technology and multiple access technology have greatly improved the system capacity and spectrum efficiency.Perfect Channel State Information(CSI)is a prerequisite for these technologies to take effect.The pilot overhead of the existing method for acquiring CSI is proportional to the number of antennas and the number of users,pilot multiplexing will seriously affect the performance of the system.The non-orthogonal efficient pilot transmission mode is beneficial for the system to achieve better results between pilot overhead and performance.This thesis aims to improve the system spectral efficiency.Based on the existing multi-antenna systems and multiple-access systems,this paper studies pilot transmission schemes with higher spectrum utilization.The non-orthogonal pilot frequency placement of the system and detection algorithm are researched combined with the characteristics of each system to design the pilot pattern and balanced the consider of the system spectrum efficiency and transmission performance.Firstly,the existing pilot placement methods and channel estimation methods of multi-antenna systems are introduced,the current research status of pilots in nonorthogonal multiple access systems are explained.Secondly,the efficient pilot transmission schemes of the Multiple Input Multiple Output(MIMO)system and the Spatial Modulation(SM)system is introduced respectively.Aiming at the problem of spectrum efficiency,a new pilot superimposed transmission is proposed.The method and receive detection algorithm verify the effectiveness of the transmission scheme through numerical simulation.Thirdly,the pilot overhead of subcarrier index modulation OFDM system(SIMOFDM)is addressed.An improved comb is proposed for multi-antenna SIM-OFDM based on the existing pilot transmission scheme.The superimposed pilot placement method further improves the system spectrum utilization by sparsely placing pilot superimposed data,and uses iterative detection and interference cancellation receivers to improve system performance.In the case of the multi-antenna multi-layer SIM-OFDM system,an efficient pilot superimposition modulation data transmission scheme and receiving end detection method are given,the simulation proves the spectrum advantage of the multi-layer system.Finally,the superimposed pilot transmission scheme is presented on the nonorthogonal multiple access system,two channel estimation algorithms are given combined with the iterative detection receiver.The simulation proves the improved algorithm's performance advantage.Then the thesis is summarized and the future research direction is given.