Research On Detection Of Spectrally Efficient Frequency Division (SEFDM) Optics Communication System

The SEFDM(Spectrally Efficient Frequency Division Multiplexing)technology is a new multi-carrier non-orthogonal transmission modulation scheme developed on the basis of OFDM(orthogonal frequency division multiplexing).Although the SEFDM system has improved bandwidth utilization,the non-orthogonality between subcarriers has caused serious Inter-Carrier Interference(ICI),forcing the receiver to use a computationally complex algorithm to complete signal detection.This thesis mainly researches and experimentally verifies the algorithm of the SEFDM system detector.First,the related technologies and basic principles of SEFDM system are introduced in detail.Based on the analysis and calculation formula of the modulation and demodulation principle of the SEFDM system,the principle of ICI formation in the SEFDM system is studied.Based on this,two generation schemes for SEFDM signals are also introduced,an IFr FT(inverse fractional Fourier transform)generated SEFDM signal and an IDFT(inverse discrete Fourier transform)generated SEFDM signal.And Analyze and compare the two schemes.Then,based on the research of SEFDM technology,this thesis proposes a new joint IQ separation iterative algorithm and Fourier transform-based detection(IQID-FFT)algorithm.ML)detection,zero-forcing(ZF)detection,iterative(ID)detection,fixed spherical decoding(FSD)detection,and joint ID-FSD detection are analyzed and compared in terms of calculation volume and BER performance.Finally,this thesis studies the principle and scheme of direct detection light detection,and builds the DDO-SEFDM/QAM system platform.In the joint simulation platform based on Matlab and VPI,whenBER=3.8×10~3,in the simulated fiber optic system,the OSNR required by the IQID-FFT algorithm was reduced by 0.44d B compared to the ID-FSD algorithm.In the established experimental platform,whenBER=3.8×10~3,the required received optical power of the proposed IQID-FFT algorithm in the optical fiber link was reduced by 0.59d B compared to the ID-FSD algorithm.Based on experimental data,the performance of the proposed detector scheme is improved while reducing the amount of calculation.