The Key Technology Of Full Duplex Digital Domain Interference Suppression For UAV High-Speed Transmission

With huge advantages in scale,cost and effectiveness,Unmanned aerial vehicle(UAV)swarm combat has achieved rapid development in recent years.Faced with the operational requirements of real-time sharing of large-capacity battlefield situational awareness information,it is urgent to improve the efficiency of information collaborative transmission among UAVs and achieve the operational goal of efficient collaboration between unmanned platforms.At the same time,the same frequency full duplex technology can receive the transmitted information from other platforms at the same frequency while sending information.Compared with the traditional half duplex technology,the frequency spectrum efficiency can be doubled theoretically.This thesis focuses on the technology of simultaneous full-duplex digital domain interference suppression for efficient information transmission in unmanned aerial vehicle scenarios.The specific research content is as follows:Firstly,according to the demand of high-speed transmission of unmanned aerial vehicles,the full-duplex physical layer transmission waveform with the same frequency is designed,including the frame structure of physical layer,time synchronization mechanism and full-duplex interference suppression structure.Using high rate low density parity check code channel coding and high order orthogonal amplitude modulation technology,the physical layer frame structure and time synchronization mechanism of full-duplex transmission waveform are designed,and the high spectral efficiency transmission goal is realized.In this thesis,the engineering requirements of simultaneous co-channel interference suppression capability are analyzed theoretically,and the overall architecture of full-duplex self-interference suppression including analog domain and digital domain is designed.Secondly,two digital interference suppression algorithms in time domain and frequency domain are designed and analyzed theoretically,and simulation verification is completed.Based on the iterative least squares criterion,a time-domain parallel selfinterference reconstruction cancellation algorithm is designed to minimize the residual interference power and meet the requirements of high-speed data processing.On the other hand,a low complexity interference suppression algorithm is designed based on the orthogonal characteristics of the expected signal and the demodulation reference signal in the frame structure of the self-interference signal.The receiver performs the estimation and reconstruction of the self-interference channel in the frequency domain,and finally completes the self-interference cancellation.Finally,two kinds of interference suppression algorithms in time domain and frequency domain are simulated under different channel conditions,and the results are analyzed in detail.Finally,the digital domain interference suppression of full-duplex transmission of unmanned aerial vehicle is realized and verified.In this thesis a full duplex high-speed transmission system is designed and a verification platform is built.Based on fieldprogrammable gate array hardware platform,the implementation workflow of digital domain interference suppression key algorithm is given in detail,and the frequency domain interference suppression algorithm is implemented by Verilog language.The performance of frequency domain interference suppression algorithm is tested in outdoor scenes,and the outdoor test results show that,the performance of the digital domain interference suppression algorithm can meet the requirement of the full duplex high-speed transmission of unmanned aerial vehicles.The research results of this thesis can be applied to the high-speed data transmission between airborne,shipborne and vehicle-mounted manned/unmanned platforms to achieve efficient collaboration and information sharing between platforms.