Low density parity check code (LDPC) is a linear block code whose performance is close to Shannon's limit. Compared with other decoding algorithms, it has low decoding complexity and flexible structure. So it beco...
详细信息
Low density parity check code (LDPC) is a linear block code whose performance is close to Shannon's limit. Compared with other decoding algorithms, it has low decoding complexity and flexible structure. So it becomes people's research hotspots. In recent years, LDPC code codec algorithm has been improved, and is widely used in deep space communications, optical fiber communications, mobile communications and underwater and other fields. Using chaotic sequence single-layer mapping plus pixel scrambling can complete chaotic image encryption, because some chaotic sequence is poor robust, in the process of channel transmission, it is difficult to ensure that the information can be destroyed after the attack In this paper, LDPC codes are introduced, and in the chaotic image encryption, block coding is used to form error protection to improve the stability of the image transmission process and improve the transmission quality.
Courtois-Finiasz-Sendrier (CFS) digital signature algorithm, which proposed in 2001, is the most important code based digital signature algorithm and can resist the known attack of quantum algorithms such as Shor algo...
详细信息
Courtois-Finiasz-Sendrier (CFS) digital signature algorithm, which proposed in 2001, is the most important code based digital signature algorithm and can resist the known attack of quantum algorithms such as Shor algorithm and Grover algorithm. But the efficiency of CFS is very low because of the extremely low signing speed and the large public key size. In this paper, a variation of CFS algorithm is presented. Instead of the Goppa code and the Patterson decoding algorithm, the new algorithm selects the Quasi-Cyclic Low Density Parity Check (QC-LDPC) code and the Belief Propagation (BP) decoding algorithm in the signing process. Compared with CFS algorithm, the new algorithm greatly reduces the storage space of public key and improves the efficiency of signature without compromising the security.
Orthogonal frequency division multiplexing-based pattern division multiple access (PDMA) is considered as a promising multiple access scheme for future wireless communication systems due to its high spectral efficienc...
详细信息
Orthogonal frequency division multiplexing-based pattern division multiple access (PDMA) is considered as a promising multiple access scheme for future wireless communication systems due to its high spectral efficiency and powerful ability to support massive users. In this study, it is shown that two pattern matrices with unequal diversity gain in the PDMA system have better convergence performance compared with the signature matrices in a traditional low-density signature multiple access system by simulations and extrinsic information transfer (EXIT) chart analysis. For a low-density parity check (LDPC)-coded PDMA system, the EXIT characteristics between the front-end multiple-user detector (MUD) and the LDPC decoder may be mismatch, which usually leads to degraded performance when an iterative detection and decoding algorithm is used. To overcome this problem, a two-stage iterative optimisation algorithm, which is easy to implement is proposed to find an optimal (near optimal) degree distribution pair for the LDPC code. Both EXIT chart analysis and simulation results demonstrate that the proposed algorithm exhibits further performance gain compared with regular (3,6) LDPC-coded systems under both an additive white Gaussian noise channel and a Rayleigh fading channel.
In this paper, a weighted multiple bit flipping (WMBF) algorithman for decoding low-density parity-check (LDPC) codes is proposed first. Then the improved WMBF algorithm which we call the efficient weighted bit-flippi...
详细信息
In this paper, a weighted multiple bit flipping (WMBF) algorithman for decoding low-density parity-check (LDPC) codes is proposed first. Then the improved WMBF algorithm which we call the efficient weighted bit-flipping (EWBF) algorithm is developed. The EWBF algorithm can dynamically choose either multiple bit-flipping or single bit-flipping in each iteration according to the log-likelihood ratio of the error probability of the received bits. Thus, it can efficiently increase the convergence speed of decoding and prevent the decoding process from falling into loop traps. Compared with the parallel weighted bit-flipping (PWBF) algorithm, the EWBF algorithm can achieve significantly lower computational complexity without performance degradation when the Euclidean geometry (EG)-LDPC codes are decoded. Furthermore, the flipping criterion does not require any parameter adjustment.
Low-density parity-check (LDPC) codes have excellent performance for a wide range of applications at reasonable complexity. LDPC codes with short blocks avoid the high latency of codes with large block lengths, making...
详细信息
Low-density parity-check (LDPC) codes have excellent performance for a wide range of applications at reasonable complexity. LDPC codes with short blocks avoid the high latency of codes with large block lengths, making them potential candidates for ultra reliable low-latency applications of future wireless standards. In this work, a novel informed dynamic scheduling (IDS) strategy for decoding LDPC codes, denoted reliability-based residual belief propagation (Rel-RBP), is developed by exploiting the reliability of the message and the residuals of the possible updates to choose the messages to be used by the decoding algorithm. A different measure for each iteration of the IDS schemes is also presented, which underlies the high cost of those algorithms in terms of computational complexity and motivates the development of the proposed strategy. Simulations show that Rel-RBP speeds up the decoding at reduced complexity and results in error rate performance gains over prior work.
In this work we consider one possible approach of realization of the generalized (L, G)-codes with a separable polynomial G(x) and rational functions with a denominator degree greater than 1 as the locators set L.
ISBN:
(数字)9781728149448
ISBN:
(纸本)9781728149455
In this work we consider one possible approach of realization of the generalized (L, G)-codes with a separable polynomial G(x) and rational functions with a denominator degree greater than 1 as the locators set L.
The LDPC codes are Shannon Limit codes that can achieve low bit error rates for SNR applications. The features of LDPC Codes are reduction in the decoding time, latency and as well as no error-floors at high SNRs. The...
详细信息
The LDPC codes are Shannon Limit codes that can achieve low bit error rates for SNR applications. The features of LDPC Codes are reduction in the decoding time, latency and as well as no error-floors at high SNRs. The proposed algorithms are SBF, MSA, and MLDD. The various decoding algorithms have been compared for these codes. The parameters are describing the which algorithm further helps in selecting the better decoder used for Medical and Signal Processing Applications. These codes are also used in Generating the Barcodes depends on the size of the Parity Check matrix. (C) 2017 The Authors. Published by Elsevier B.V.
The situation resulted from the solution of Shannon problem by optimization theory of error-correcting coding in the applied studies of coding theory is analyzed. Unresolved problems of classical (algebraic) theory ar...
详细信息
ISBN:
(数字)9781728175287
ISBN:
(纸本)9781728175294
The situation resulted from the solution of Shannon problem by optimization theory of error-correcting coding in the applied studies of coding theory is analyzed. Unresolved problems of classical (algebraic) theory are discussed. The results for main clusters of decoding algorithms built on the basis of Optimization Theory (OT) are considered. Further tasks for OT development are given, the methods for their solution are offered. Broad possibilities shown by new versions of Viterbi algorithm are mentioned. Advantages of main OT paradigms including the advantages of symbolic codes and divergent coding are shown. A special group of decoding algorithms with direct metrics control (DDMC) is singled out. The main ways to develop coding theory for the coming years and for the future are listed.
We show that quantum expander codes, a constant-rate family of quantum low-density parity check (LDPC) codes, with the quasi linear time decoding algorithm of Leverrier, Tillich and Zemor can correct a constant fracti...
详细信息
ISBN:
(纸本)9781450355599
We show that quantum expander codes, a constant-rate family of quantum low-density parity check (LDPC) codes, with the quasi linear time decoding algorithm of Leverrier, Tillich and Zemor can correct a constant fraction of random errors with very high probability. This is the first construction of a constant-rate quantum LDPC code with an efficient decoding algorithm that can correct a linear number of random errors with a negligible failure probability. Finding codes with these properties is also motivated by Gottesman's construction of fault tolerant schemes with constant space overhead. In order to obtain this result, we study a notion of alpha-percolation: for a random subset E of vertices of a given graph, we consider the size of the largest connected alpha-subset of E, where Xis an alpha-subset of E if vertical bar X boolean AND E vertical bar >= alpha vertical bar X vertical bar.
A modified method for general LDPC bit-flipping decoding is proposed in this *** proposed method consists of two parts:multi-bit flipping judgement algorithm and multi-bit flipping compensation algorithm,the first par...
详细信息
A modified method for general LDPC bit-flipping decoding is proposed in this *** proposed method consists of two parts:multi-bit flipping judgement algorithm and multi-bit flipping compensation algorithm,the first part trying to find the maximum acceptable number of bits to flipping at the same time to accelerated convergence process,and the second part to compensates the new errors introduced by the first *** proposed decoding method can be easily used to modify different BF algorithms which means the hardware implementation is *** simulation results show that the proposed method can achieve 2.75% to 36.05% of bit-flipping timing reduction,3.0% to 18.1% of BER reduction at SNR 0.2 dB to 4 dB compared with classic BF,IMWBF,LCWBF,and RRWBF.
暂无评论