Alternate Iteration of Shuffled Belief Propagation Decoding

Low-Density Parity-Check (LDPC) codes are usually decoded by running an iterative decoding algorithm, such as belief-propagation (BP), over the factor graph of the codes. The standard BP schedule is a parallelizable decoding, using the same pre-update information during updating all the check nodes and bit nodes. In order to improve the convergence speed in terms of number of iterations, several sequential schedules were studied, such as the Layered belief-propagation (LBP) and the Shuffled belief-propagation (SBP). Correspondingly, for these serial decoding algorithms, the messages were generated by using the latest available information. In this paper, a modified shuffled version of iterative decoding of low-density parity-check codes is present by changing the updating order at bit nodes. Compared with the plain shuffled version, the proposed scheme has the same convergence rate which is twice as the conventional belief propagation, and can reduce complexity without any performance degradation. At last, the simulation result was shown with respect to the LDPC codes in CMMB standard.