应用于偏振模色散补偿系统中的前向纠错技术的研究

北京邮电大学硕士学位论文AbstractOptical fibre communications have been expected to be a high-speed andhigh-capacity communication,which has a lot of advantages such as low loss,highspectra capacity,small size,low weight.In the early period,due to the development ofoptical fibre and relevant optoelectronic equipments and devices,system performancewas so good that forward error correction technique was not even needed to be usedin fibre communication system,and the relatively faster optical information rate madethat error correction did not match the codec with the transmission system.Until thelight transmission rate gone up to the Gb/s,and the transmission distance withoutrepeaters had been extended by the applying of optical amplification,some factorssuch as polarization mode dispersion,were found to be bottleneck in the furtherimprovement of system performance,while these factors in the short-range,low-ratesystem was not obvious,.So the research of FEC applied in optical communicationsystem started.LDPC code is near the Shannon limit performance of "good"code andthe decoding complexity is relatively low.The polarization mode dispersioncompensation and polarization mode dispersion mitigation (FEC)in combination hassome theoretical and practical value.Brief introduction of the production mechanism of polarization mode dispersion,the representation of state of polarization (SOP and the related concept offeedback control algorithm for polarization mode dispersion.Introduction of some basic concepts and the definition of low-densityparity-check (LDPC)codes (which currently has the best theoreticalperformance),the method for constructing and the H matrix,and somecommonly used decoding method,such as......(SPA )and bit reversal algorithms(bit-flipping).LDPC codes are compared with the Gaussian channel is transmitted in opticalfibre transmission error correction performance of the simulator,numericalsimulation and the specific discussion,concluded that the LDPC codes for opticalfiber transmission to reduce the error rate and improve the tolerance of PMDPlayed a good role.Obtained simulation result of 5-6dB BER improvement for10Gb/s OOK transmission by using both PMDC and LDPC.The error correction performance of LDPC codes in the Gaussian channel and theoptical fiber transmission system with PMD simulator have been simulated andcompared.It has been proofed that he LDPC codes for optical fiber transmission