Multi - LDPC Code Decoding And Hardware Realization In Optical Communication

LDPC codes (Low Density Parity Check Codes) overcome the shortcomings ofother error correcting codes,which show high performance in decoding process.Itschannel capacity is close to Shannon limit,so it has been got wide attention since itwas rediscovered.As a hot research topic in the field of channel coding,LDPC codesshow a strong competitive advantage and have been considered as the first choice ofthe future generation mobile communication coding scheme.The phenomenon that binary LDPC code is adopted in optical fibercommunication is very common at present. However,nonbinary LDPC codes showsthe ability of better error correction and better burst error resistance under thecondition of the same parameters.So nonbinary LDPC codes is more applicable tohigh-speed communication system like optical fiber communication.In our paper,we propose some new decoding algorithm of nonbinary LDPC codessuch as serial min-max decoding algorithm and serial min-max decoding algorithmbased on variable weighting after discussing the exist decoding algorithm.Abouthardware implements,we design a decoder by FPGA which is at the basis of serialmin-max decoding algorithm based on variable weighting.And the performance isproved well by its waveform simulation.Given the above conditions,we show the research mainly by the followingsections.Firstly,we introduce the basic theory of nonbinary LDPC codes after knowingoptical fiber communication system and the necessity that imports channel decodingin optical fiber communication.And we give a detailed description of nonbinaryLDPC codes from basic concept、express method、construction method and theperformance comparison with binary LDPC codes.Secondly,we show some classical decoding algorithm like BP algorithm、decoding algorithm in log-domain、the min-sum algorithm and the min-max decodingalgorithm.Further more,we propose serial min-max decoding algorithm and serialmin-max decoding algorithm based on variable weighting.Besides,we do an analysisof introduced algorithm from the aspect of code length、the number of iteration and performance.Thirdly,we discuss the importance of quantification of initial information andshow the hardware design scheme of serial min-max decoding algorithm based onvariable weighting,which verifies the correctness of the algorithm by specificwaveform simulation.Its superior performance indicates that the proposed algorithm istruly suitable for future optical fiber communication.Lastly, we make a summing up of the researched work and point out the directionof future research.