Research on a Fast Decoding Method of the Quasi-cyclic LDPC Codes Based on Serial Message-Passing Schedule
基于串行消息传递机制的QC-LDPC码快速译码算法研究

A new fast decoding method of Quasi-Cyclic LDPC(QC-LDPC)codes, named semi-serial decoding algorithm, is presented through contraposing the shortcoming of flood decoding method.For the algorithm, the message was updated in a serial sequence of m subsets of check nodes(or variable nodes), while the check nodes(or variable nodes) in the same subset are updated simultaneously. In this way,the decoding speed would be faster than the common serial decoding algorithm several times. An efficient grouping method suitable for the quasi-cyclic LDPC codes based on the circulant architecture is proposed.Simulation results show that,under the same complexiry,the proposed algorithm fastens the decoding speed of quasi-cyclic LDPC codes, meanwhile, it inherits all the merits of the serial massage-passing decoding algorithm. The conclusion is that the speed of the semi-serial decoding method is at least p times than that of the serial one(p is the number of rows of the cyclic permutation matrix in the parity check matrix of quasi-cyclic LDPC codes).