Constructions Of QC-LDPC Codes For Optical Communication

Quasi-cyclic low-density parity-check code is an important subclass of LDPCcodes, whose parity-check matrix consists of smaller null-matrices and cyclic-matrices,and has excellent performance, especially in hardware implementation and practicalapplication, because of its convenient storage and access advantages, it greatly reducesthe decoder complexity and by adding the feedback shift register, it can achieve linearencoding complexity, hence obtains the widespread application, and become the newresearch hotspot.This paper summarizes two generic iterative decoding algorithms, aiming at thecharacteristics of high speed, high efficiency optical fiber communication system andbasing on the qualities of finite field, Euclidean geometry and difference invariant sets,and puts forward three kinds of high speed, low error platform, simple hardwareimplementation of QC-LDPC codes, and gives the simulation results in the AWGNchannel, in the last compares the corresponding rate with the Shannon limit.