Because of the speed limitation of the conventional bit-selection strategy in the exi- sting weighted bit flipping algorithms, a high- speed Low-Density Parity-Check （LDPC） dec- oder cannot be realised. To solve thi...Because of the speed limitation of the conventional bit-selection strategy in the exi- sting weighted bit flipping algorithms, a high- speed Low-Density Parity-Check （LDPC） dec- oder cannot be realised. To solve this problem, we propose a fast weighted bit flipping algo- rithm. Specifically, based on the identically dis- tributed error bits, a parallel bit-selection met- hod is proposed to reduce the selection delay of the flipped bits. The delay analysis demon- strates that, the decoding speed of LDPC codes can be significantly improved by the proposed algorithm. Furthermore, simulation results ver- ify the validity of the proposed algorithm.展开更多
Efficient reconciliation is a crucial step in continuous variable quantum key distribution. The progressive-edge-growth(PEG) algorithm is an efficient method to construct relatively short block length low-density pari...Efficient reconciliation is a crucial step in continuous variable quantum key distribution. The progressive-edge-growth(PEG) algorithm is an efficient method to construct relatively short block length low-density parity-check(LDPC) codes. The qua-sicyclic construction method can extend short block length codes and further eliminate the shortest cycle. In this paper, by combining the PEG algorithm and quasi-cyclic construction method, we design long block length irregular LDPC codes with high error-correcting capacity. Based on these LDPC codes, we achieve high-efficiency Gaussian key reconciliation with slice recon-ciliation based on multilevel coding/multistage decoding with an efficiency of 93.7%.展开更多
In view of the problems that the encoding complexity of quasi-cyclic low-density parity-check(QC-LDPC) codes is high and the minimum distance is not large enough which leads to the degradation of the error-correction ...In view of the problems that the encoding complexity of quasi-cyclic low-density parity-check(QC-LDPC) codes is high and the minimum distance is not large enough which leads to the degradation of the error-correction performance, the new irregular type-Ⅱ QC-LDPC codes based on perfect cyclic difference sets(CDSs) are constructed. The parity check matrices of these type-Ⅱ QC-LDPC codes consist of the zero matrices with weight of 0, the circulant permutation matrices(CPMs) with weight of 1 and the circulant matrices with weight of 2(W2CMs). The introduction of W2CMs in parity check matrices makes it possible to achieve the larger minimum distance which can improve the error-correction performance of the codes. The Tanner graphs of these codes have no girth-4, thus they have the excellent decoding convergence characteristics. In addition, because the parity check matrices have the quasi-dual diagonal structure, the fast encoding algorithm can reduce the encoding complexity effectively. Simulation results show that the new type-Ⅱ QC-LDPC codes can achieve a more excellent error-correction performance and have no error floor phenomenon over the additive white Gaussian noise(AWGN) channel with sum-product algorithm(SPA) iterative decoding.展开更多
基金supported in part by the National Natural Science Foundation of China under Grant No.61072069the Fundamental Research Funds for the Central Universities under Grant No.72001859+1 种基金the Important National Science and Technology Specific Projects under Grant No.2011ZX03003-001-04the One Church,One Family,One Purpose Project(111 Project)under Grant No.B08038
文摘Because of the speed limitation of the conventional bit-selection strategy in the exi- sting weighted bit flipping algorithms, a high- speed Low-Density Parity-Check （LDPC） dec- oder cannot be realised. To solve this problem, we propose a fast weighted bit flipping algo- rithm. Specifically, based on the identically dis- tributed error bits, a parallel bit-selection met- hod is proposed to reduce the selection delay of the flipped bits. The delay analysis demon- strates that, the decoding speed of LDPC codes can be significantly improved by the proposed algorithm. Furthermore, simulation results ver- ify the validity of the proposed algorithm.
基金supported by the National Natural Science Foundation of China(Grant No.61378010)the Natural Science Foundation of Shanxi Province(Grant No.2014011007-1)
文摘Efficient reconciliation is a crucial step in continuous variable quantum key distribution. The progressive-edge-growth(PEG) algorithm is an efficient method to construct relatively short block length low-density parity-check(LDPC) codes. The qua-sicyclic construction method can extend short block length codes and further eliminate the shortest cycle. In this paper, by combining the PEG algorithm and quasi-cyclic construction method, we design long block length irregular LDPC codes with high error-correcting capacity. Based on these LDPC codes, we achieve high-efficiency Gaussian key reconciliation with slice recon-ciliation based on multilevel coding/multistage decoding with an efficiency of 93.7%.
基金supported by the National Natural Science Foundation of China(No.61472464)the Research Foundation of Education Bureau of Hunan Province in China(No.16C0686)the Key Discipline Construction Project Funding for Hunan University of Science and Engineering(Electrical systems)
文摘In view of the problems that the encoding complexity of quasi-cyclic low-density parity-check(QC-LDPC) codes is high and the minimum distance is not large enough which leads to the degradation of the error-correction performance, the new irregular type-Ⅱ QC-LDPC codes based on perfect cyclic difference sets(CDSs) are constructed. The parity check matrices of these type-Ⅱ QC-LDPC codes consist of the zero matrices with weight of 0, the circulant permutation matrices(CPMs) with weight of 1 and the circulant matrices with weight of 2(W2CMs). The introduction of W2CMs in parity check matrices makes it possible to achieve the larger minimum distance which can improve the error-correction performance of the codes. The Tanner graphs of these codes have no girth-4, thus they have the excellent decoding convergence characteristics. In addition, because the parity check matrices have the quasi-dual diagonal structure, the fast encoding algorithm can reduce the encoding complexity effectively. Simulation results show that the new type-Ⅱ QC-LDPC codes can achieve a more excellent error-correction performance and have no error floor phenomenon over the additive white Gaussian noise(AWGN) channel with sum-product algorithm(SPA) iterative decoding.
