Abstract
Low-density parity-check (LDPC) codes can be applied in a lot of different scenarios such as video broadcasting and satellite communications. LDPC codes are commonly decoded by an iterative algorithm called belief propagation (BP) over the corresponding Tanner graph. The original BP updates all the variable-nodes simultaneously, followed by all the check-nodes simultaneously as well. We propose a sequential scheduling algorithm based on weighted bit-flipping (WBF) algorithm for the sake of improving the convergence speed. Notoriously, WBF is a low-complexity and simple algorithm. We combine it with BP to obtain advantages of these two algorithms. Flipping function used in WBF is borrowed to determine the priority of scheduling. Simulation results show that it can provide a good tradeoff between FER performance and computation complexity for short-length LDPC codes.
Highlights
Low-density parity-check (LDPC) codes were first invented by Gallager [1] but had been neglected for decades until Mackay brought them back to light in 1996 [2]
Much attention had been attracted for their excellent Shannon limit approaching error-correcting performance through belief propagation (BP) [3] decoding algorithm
The decoding performance of the Flood, CSBP, and WBFbased serial BP (WBFSBP) over additive white Gauss noise (AWGN) channels is presented in this part
Summary
Low-density parity-check (LDPC) codes were first invented by Gallager [1] but had been neglected for decades until Mackay brought them back to light in 1996 [2]. Much attention had been attracted for their excellent Shannon limit approaching error-correcting performance through belief propagation (BP) [3] decoding algorithm. The messages are computed in a serial manner using the newest updated information. Sequential strategies were introduced as a sequence updates based on check-node (CSBP) [13,14,15] or variable-node (VSBP) [16, 17]. Simulations demonstrate that sequential strategies converge about twice as fast as the standard parallel BP decoding algorithms (Flood) without any extra computing burden. In order to achieve the tradeoff between decoding performance and computational complexity, a low-complexity sequential WBF-based scheduling algorithm is proposed, in which the priority used in WBF determines the order of scheduling.
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