scholarly journals A New Reliability Ratio Weighted Bit Flipping Algorithm for Decoding LDPC Codes

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Chakir Aqil ◽  
Ismail Akharraz ◽  
Abdelaziz Ahaitouf
Keyword(s):  
Gaussian Noise ◽  
Additive White Gaussian Noise ◽  
Ldpc Codes ◽  
Low Density ◽  
Parity Check ◽  
Coding Gain ◽  
Decoding Complexity ◽  
Low Density Parity Check ◽  
Awgn Channel ◽  
Infinite Loop

In this study, we propose a “New Reliability Ratio Weighted Bit Flipping” (NRRWBF) algorithm for Low-Density Parity-Check (LDPC) codes. This algorithm improves the “Reliability Ratio Weighted Bit Flipping” (RRWBF) algorithm by modifying the reliability ratio. It surpasses the RRWBF in performance, reaching a 0.6 dB coding gain at a Binary Error Rate (BER) of 10−4 over the Additive White Gaussian Noise (AWGN) channel, and presents a significant reduction in the decoding complexity. Furthermore, we improved NRRWBF using the sum of the syndromes as a criterion to avoid the infinite loop. This will enable the decoder to attain a more efficient and effective decoding performance.

EFFICIENT RECOVERY TECHNIQUE FOR LOW-DENSITY PARITY-CHECK CODES USING REDUCED-SET DECODING

2008 ◽  
Vol 17 (02) ◽  
pp. 333-351 ◽  
Author(s):  
K. M. S. SOYJAUDAH ◽  
P. C. CATHERINE
Keyword(s):  
Ldpc Codes ◽  
Low Density ◽  
Parity Check ◽  
Coding Gain ◽  
Inference Procedure ◽  
Recovery Algorithm ◽  
Low Density Parity Check ◽  
Recovery Technique ◽  
Efficient Recovery ◽  
Parity Check Codes

We introduce a recovery algorithm for low-density parity-check codes that provides substantial coding gain over the conventional method. Concisely, it consists of an inference procedure based on successive decoding rounds using different subsets of bit nodes from the bipartite graph representing the code. The technique also sheds light on certain characteristics of the sum–product algorithm and effectively copes with the problems of trapping sets, cycles, and other anomalies that adversely affect the performance LDPC codes.

scholarly journals Design of Nonbinary LDPC Cycle Codes with Large Girth from Circulants and Finite Fields

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Hengzhou Xu ◽  
Huaan Li ◽  
Jixun Gao ◽  
Guixiang Zhang ◽  
Hai Zhu ◽  
...  
Keyword(s):  
Finite Fields ◽  
Gaussian Noise ◽  
Iterative Decoding ◽  
Additive White Gaussian Noise ◽  
Ldpc Codes ◽  
Parity Check ◽  
Undirected Graphs ◽  
Awgn Channel ◽  
Exponent Matrix ◽  
Large Girth

In this paper, we study a class of nonbinary LDPC (NBLDPC) codes whose parity-check matrices have column weight 2, called NBLDPC cycle codes. We propose a design framework of 2 , ρ -regular binary quasi-cyclic (QC) LDPC codes and then construct NBLDPC cycle codes of large girth based on circulants and finite fields by randomly choosing the nonzero field elements in their parity-check matrices. For enlarging the girth values, our approach is twofold. First, we give an exhaustive search of circulants with column/row weight ρ and design a masking matrix with good cycle distribution based on the edge-node relation in undirected graphs. Second, according to the designed masking matrix, we construct the exponent matrix based on finite fields. The iterative decoding performances of the constructed codes on the additive white Gaussian noise (AWGN) channel are finally provided.

Rate and Performance Enhancement of LDPC Codes Using Collection of Punctured Codes Decoding (CPCD)

2021 ◽  
Vol 11 ◽  
Author(s):  
Rana A. Hassan ◽  
John P. Fonseka
Keyword(s):  
Communication Systems ◽  
Ldpc Codes ◽  
Superior Performance ◽  
Low Density ◽  
Parity Check ◽  
Decoding Complexity ◽  
Low Density Parity Check ◽  
Punctured Codes ◽  
Punctured Code ◽  
Decoding Delay

Background: Low-density parity-check (LDPC) codes have received significant interest in a variety of communication systems due to their superior performance and reasonable decoding complexity. Methods: A novel collection of punctured codes decoding (CPCD) technique that considers a code as a collection of its punctured codes is proposed. Two forms of CPCD, serial CPCD that decodes each punctured code serially and parallel CPCD that decodes each punctured code in parallel, are discussed. Results: It is demonstrated that both serial and parallel CPCD have about the same decoding complexity compared with standard sum product algorithm (SPA) decoding. It is also demonstrated that while serial CPCD has about the same decoding delay compared with standard SPA decoding, parallel CPCD can decrease the decoding delay, however, at the expense of processing power. Conclusion: Numerical results demonstrate that CPCD can significantly improve the performance, or significantly increase the code rate of low-density parity-check (LDPC) codes.

scholarly journals Performance of Hybrid RF/FSO Cooperative Systems Based on Quasicyclic LDPC Codes and Space-Coupled LDPC Codes

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Ibrahima Gueye ◽  
Ibra Dioum ◽  
Idy Diop ◽  
K. Wane Keita ◽  
Papis Ndiaye ◽  
...  
Keyword(s):  
Communication Systems ◽  
Additive White Gaussian Noise ◽  
Ldpc Codes ◽  
Cooperative Systems ◽  
Error Correcting Codes ◽  
Cooperative Transmission ◽  
Low Density ◽  
Parity Check ◽  
Transmission Systems ◽  
Low Density Parity Check

Free space optical (FSO) communication systems provide wireless line of sight connectivity in the unlicensed spectrum, and wireless optical communication achieves higher data rates compared to their radio frequency (RF) counterparts. FSO systems are particularly attractive for last mile access problem by bridging fiber optic backbone connectivity to RF access networks. To cope with this practical deployment scenario, there has been increasing attention to the so-called dual-hop (RF/FSO) systems where RF transmission is used at a hop followed by FSO transmission to another. In this article, we study the performance of cooperative transmission systems using a mixed RF-FSO DF (decode and forward) relay using error-correcting codes including QC-LDPC codes at the relay level. The FSO link is modeled by the gamma-gamma distribution, and the RF link is modeled by the Additive White Gaussian Noise (AWGN) model. Another innovation in this article is the use of cooperative systems using a mixed FSO/RF DF relay using quasicyclic low-density parity check (QC-LDPC) codes at the relay level. We also use the space-coupled low-density parity check (SC-LDPC) codes on the same scheme to show its importance in cooperative optical transmission but also in hybrid RF/FSO transmission. The latter will be compared with QC-LDPC codes. The use of mixed RF/FSO cooperative transmission systems can improve the reliability and transmission of information in networks. The results demonstrate an improvement in the performance of the cooperative RF/FSO DF system based on QC-LDPC and SC-LDPC codes compared to RF/FSO systems without the use of codes, but also to the DF systems proposed in the existing literature.

scholarly journals Low-complexity decoding of LDPC codes using reduced-set WBF-based algorithms

2020 ◽  
Vol 2020 (1) ◽  
Author(s):  
Sadjad Haddadi ◽  
Mahmoud Farhang ◽  
Mostafa Derakhtian
Keyword(s):  
Computational Complexity ◽  
Error Rate ◽  
Ldpc Codes ◽  
Low Complexity ◽  
Low Density ◽  
Parity Check ◽  
Decoding Complexity ◽  
Iterative Decoders ◽  
Low Density Parity Check ◽  
The Difference

Abstract We propose a method to substantially reduce the computational complexity of iterative decoders of low-density parity-check (LDPC) codes which are based on the weighted bit-flipping (WBF) algorithm. In this method, the WBF-based decoders are modified so that the flipping function is calculated only over a reduced set of variable nodes. An explicit expression for the achieved complexity gain is provided and it is shown that for a code of block length N, the decoding complexity is reduced from O(N2) to O(N). Moreover, we derive an upper bound for the difference in the frame error rate of the reduced-set decoders and the original WBF-based decoders, and it is shown that the error performances of the two decoders are essentially the same.

AN EXPLORATION OF NON-ASYMPTOTIC LOW-DENSITY, PARITY CHECK ERASURE CODES FOR WIDE-AREA STORAGE APPLICATIONS

2007 ◽  
Vol 17 (01) ◽  
pp. 103-123 ◽  
Author(s):  
JAMES S. PLANK ◽  
MICHAEL G. THOMASON
Keyword(s):  
Storage Systems ◽  
Distributed Storage ◽  
Ldpc Codes ◽  
Peer To Peer ◽  
Erasure Codes ◽  
Low Density ◽  
Parity Check ◽  
Finite Systems ◽  
Low Density Parity Check ◽  
Distributed Storage Systems

As peer-to-peer and widely distributed storage systems proliferate, the need to perform efficient erasure coding, instead of replication, is crucial to performance and efficiency. Low-Density Parity-Check (LDPC) codes have arisen as alternatives to standard erasure codes, such as Reed-Solomon codes, trading off vastly improved decoding performance for inefficiencies in the amount of data that must be acquired to perform decoding. The scores of papers written on LDPC codes typically analyze their collective and asymptotic behavior. Unfortunately, their practical application requires the generation and analysis of individual codes for finite systems. This paper attempts to illuminate the practical considerations of LDPC codes for peer-to-peer and distributed storage systems. The three main types of LDPC codes are detailed, and a huge variety of codes are generated, then analyzed using simulation. This analysis focuses on the performance of individual codes for finite systems, and addresses several important heretofore unanswered questions about employing LDPC codes in real-world systems.

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