信頼度更新を用いたLDPC符号の Bit-Flipping 復号法の改良

匡 佐藤, 剛 細谷, 秀樹 八木 +1 more

洋一 稲葉, 知明 大槻

Yoichi Inaba

Recently, various decoding algorithms with Low Density Parity Check (LDPC) codes have been proposed. Most algorithms can be divided into a hard decision algorithm and a soft decision algorithm. The Weighted Bit Flipping (WBF) algorithm that is between a hard decision and a soft decision algorithms has been proposed. The Bootstrapped WBF and Modified WBF algorithms have been proposed to improve the error rate performance and decoding complexity of the WBF algorithm. In this letter, we apply the Bootstrap step to the Modified WBF algorithm. We show that the Bootstrapped modified WBF algorithm outperforms the WBF, Bootstrapped WBF, and Modified WBF algorithms. Moreover, we show that the Bootstrapped modified WBF algorithm has the lowest decoding complexity.

Khoa Le, Fakhreddine Ghaffari, David Declercq +2 more

This paper presents a new high-throughput, low-complexity Bit Flipping (BF) decoder for Low-Density Parity-Check (LDPC) codes on the Binary Symmetric Channel (BSC), called Probabilistic Parallel Bit Flipping (PPBF). The advantage of PPBF comes from the fact that, no global operation is required during the decoding process and from that, all of the computations could be parallelized and localized at the computing units. Also in PPBF, the probabilistic feature in flipping the Variable Node (VN) is incorporated for all satisfaction level of its CN neighbors. This type of probabilistic incorporation makes PPBF more dynamic to correct some error patterns which are unsolvable by other BF decoders. PPBF offers a faster decoding process with an equivalent error correction performance to the Probabilistic Gradient Descent Bit Flipping (PGDBF) decoder, which is better than all so-far introduced BF decoders in BSC channel. A hardware implementation architecture of PPBF is also presented in this paper with detailed circuits for the probabilistic signal generator and processing units. The implementation of PPBF on FPGA confirms that, the PPBF complexity is much lower than that of the PGDBF and even lower than the one of the deterministic Gradient Descent Bit Flipping (GDBF) decoder. The good decoding performance along with the high throughput and low complexity lead PPBF decoder to become a brilliant candidate for the next generation of communication and storage standards.

雅徳 廣友, 昌克 森井

Jui-Hui Hung, Sau-Gee Chen

For LDPC decoding, bit-flipping (BF) algorithms are much simpler than the min-sum algorithms (MSA). However, BF algorithms have the disadvantages of poorer performances and higher iteration counts than MSA. To increase the BF performances, this paper presents a novel BF algorithm, called Low-Correlation Multibit-flipping (LCMBF) algorithm, which flips more than one bit in each iteration. High performances are achieved by flipping those bits with low correlation as much as possible. As such, the chances of introducing additional error bits are greatly reduced. Overall, the proposed algorithm achieves better BER performances and requires less iteration numbers than conventional BF algorithms.