Research On Key Technologies Of DMT Signal Processing In Large-capacity Short-distance Optical Interconnect System

Under the background of the continuously rising data rates and a sharp increase in data center traffic,discrete multitone modulation(DMT),a multi-carrier modulation(MCM)technology,has been widely studied and applied due to its advantages of high transmission capacity and strong anti-interference ability.For the system requirements of short distance and large capacity in the data center,compared with coherent detection technology,the intensity modulation direct detection(IM/DD)system is simpler to implement and lower in cost.The system can be completed by advanced digital signal processing(DSP)technology.DSP technology improves the overall reliability and performance of the system.Based on the research of the key technologies of discrete multi-tone modulation and the structure of IM/DD system,this paper studies the key technologies of DMT signals used in short-distance large-capacity optical interconnection systems.The main research contents are as follows:1.Aiming at the problem of high peak average power ratio(PAPR)of DMT signals,selective mapping(SLM)and partial transmission sequence(PTS)are analyzed and compared in this paper.Two improved algorithms based on the traditional PTS algorithm are proposed,and the simulation proves that the improved algorithms guarantee the performance of the algorithm on the basis of greatly reducing the computational complexity of the algorithm,and the effective reduction of DMT signal PAPR is realized.2.Theoretical analysis of Subcarrier-Subcarrier Mixing Interference(SSMI)and Frequency Selective Fading(FF),which have the most serious impact on signal transmission in short-distance optical interconnection systems.This paper proposes a half-cyclic predistortion algorithm.The algorithm improves symbol synchronization accuracy while ensuring high spectral efficiency,and effectively reduces the impact of system damage on signal transmission,and improves receiver sensitivity and system performance.3.The thesis studies the basic theory of low-density parity-check(LDPC).This paper introduces LDPC code to encode the signal at the transmitter,and focuses on the decoding algorithm at the receiver.Based on the theoretical basis of BF decoding algorithm,reliability ratio based weighted multi-bit flipping(MRRWBF)is proposed.MATLAB simulation is used to prove that the algorithm can improve the decoding performance on the basis of effectively reducing the decoding iteration times.This decoding algorithm is proved to be suitable for short-distance optical interconnection systems.