Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Journal of Chongqing University of Posts and Telecommunications

Construction of LDPC codes with unequal error protection

Lin Xue

Published Jan 1, 2004• 0 citations
OpenAlex

Abstract

This paper constructs irregular LDPC codes of unequal error protection with a parity check matrix in a lower triangular. Due to the particular relation of generator matrix and parity check matrix, it can achieve unequal error protection performance with the modified decoding algorithm. Then the authors use linear shift register to simply realize encoding since the subcodes of LDPC code are quasicyclic code.

Related papers

UEP Constructions of Quasi-Cyclic Low-Density Parity-Check Codes via Masking

Chi‐Jen Wu, Chung-Hsuan Wang, Chi-chao Chao

In this paper, the algebraic constructions of quasi-cyclic low-density parity-check (QC-LDPC) codes with the unequal error protection (UEP) property are considered. A criterion for constructing such codes via the masking technique is proposed, based on which explicit conditions on the base parity-check matrices and masking matrices to achieve UEP are provided. We also give three specific constructions of UEP QC-LDPC codes. Furthermore, a sufficient condition to ensure strict UEP is presented. Simulation results demonstrate the superiority of our constructed codes over time-sharing schemes. The constructed codes also have competitive error performance against randomly constructed equal-error-protection LDPC codes and irregular UEP LDPC codes designed based on the degree distribution.

IEEE Transactions on Information Theory•Aug 17, 2017•10 citations

Unequal error protection QC-LDPC codes via Masking

Chi‐Jen Wu, Chung-Hsuan Wang, Chi-chao Chao

In this paper, a generalized construction of quasi-cyclic low-density parity-check (QC-LDPC) codes for unequal error protection (UEP) is proposed based on the masking technique. We can obtain UEP QC-LDPC codes as long as the Tanner graph of the masking matrix satisfies a general condition which can include our previous UEP construction as a special case. A sufficient condition to have flexible choice of protection levels is then presented. Simulation results show that the constructed codes can indeed provide codeword bits with different bit-error-rate performance.

International Symposium on Information Theory and its Applications•Dec 1, 2012•1 citation

An Unequal Error Protection of Quasi-Cyclic Low Density Parity Check (QC-LDPC) Codes Based on Combinatorial Designs

Bijaya Paudel, Sina Vafi

This paper presents a novel method for constructing high performance unequal error protection (UEP) quasicyclic low-density parity-check (QC-LDPC) codes. These codes are highly efficient and designed with flexible rates, lengths and number of protection levels. The given QC-LDPC codes are based on the combinatorial design. Each circulant constituting the parity check matrix of the UEP code is determined from subsets with the distinct difference between elements. Simulation results indicate that proposed UEP codes have equivalent performance to UEP codes constructed with the higher girth and lower rate, while achieving superior performance than the codes constructed by conventional equal error protection (EEP) techniques.

International Conference on Computer and Communication Systems (ICCCS)•Feb 1, 2019•4 citations

A new construction of UEP QC-LDPC codes

Chi‐Jen Wu, Chung-Hsuan Wang, Chi-chao Chao

In this paper, a new construction of quasi-cyclic low-density parity-check (QC-LDPC) codes for unequal error protection (UEP) is proposed. We first give a new class of UEP block codes. QC-LDPC codes with binomial-term parity-check matrices which can avoid girths less than 8 and achieve an enlarged upper bound on the minimum distance are also introduced. An effective UEP scheme based on the proposed UEP block codes and QC-LDPC codes which can provide flexible choice of protection levels is then presented. Simulation results show that the new QC-LDPC codes can achieve good performance and low error floors. The bits with different designed protection levels can indeed have unequal bit-error-rate performance.

IEEE International Symposium on Information Theory (ISIT)•Jun 1, 2010•4 citations

Quasi-cyclic LDPC codes for fast encoding

Seho Myung, Kyeongcheol Yang, Jaeyoel Kim

In this correspondence we present a special class of quasi-cyclic low-density parity-check (QC-LDPC) codes, called block-type LDPC (B-LDPC) codes, which have an efficient encoding algorithm due to the simple structure of their parity-check matrices. Since the parity-check matrix of a QC-LDPC code consists of circulant permutation matrices or the zero matrix, the required memory for storing it can be significantly reduced, as compared with randomly constructed LDPC codes. We show that the girth of a QC-LDPC code is upper-bounded by a certain number which is determined by the positions of circulant permutation matrices. The B-LDPC codes are constructed as irregular QC-LDPC codes with parity-check matrices of an almost lower triangular form so that they have an efficient encoding algorithm, good noise threshold, and low error floor. Their encoding complexity is linearly scaled regardless of the size of circulant permutation matrices.

IEEE Transactions on Information Theory•Jul 19, 2005•278 citations

Decoding Scheduling for Unequal Error Protection Quasi-Cyclic Low-Density Parity-Check Codes

Jia-Jyun Wu, Chung-Hsuan Wang, Chi-chao Chao

Algebraic constructions of quasi-cyclic (QC) low-density parity-check (LDPC) codes with unequal error protection (UEP) capabilities have recently been proposed, which can provide different error-correcting capabilities for different parts of the coded bits. However, conventional decoding algorithms are not designed for LDPC codes with UEP. In this paper, we propose three decoding schemes for UEP QC-LDPC codes extended from existing scheduling strategies, tailored to the special structures of the parity-check matrices. Simulation results show that the proposed schemes can provide improved error rate performance especially for coded bits on low protection levels. The decoding convergence can also be accelerated, thereby reducing the computational complexity.

International Workshop on Signal Design and its Applications in Communications•Oct 1, 2019•1 citation
This paper constructs irregular LDPC codes of unequal error protection with a parity check matrix in a lower triangular. Due to the particular relation of generator matrix and parity check matrix, it can achieve unequal error protection performance with the modified decoding algorithm. Then the authors use linear shift register to simply realize encoding since the subcodes of LDPC code are quasicyclic code.
In this paper, the algebraic constructions of quasi-cyclic low-density parity-check (QC-LDPC) codes with the unequal error protection (UEP) property are considered. A criterion for constructing such codes via the masking technique is proposed, based on which explicit conditions on the base parity-check matrices and masking matrices to achieve UEP are provided. We also give three specific constructions of UEP QC-LDPC codes. Furthermore, a sufficient condition to ensure strict UEP is presented. Simulation results demonstrate the superiority of our constructed codes over time-sharing schemes. The constructed codes also have competitive error performance against randomly constructed equal-error-protection LDPC codes and irregular UEP LDPC codes designed based on the degree distribution.
In this paper, a generalized construction of quasi-cyclic low-density parity-check (QC-LDPC) codes for unequal error protection (UEP) is proposed based on the masking technique. We can obtain UEP QC-LDPC codes as long as the Tanner graph of the masking matrix satisfies a general condition which can include our previous UEP construction as a special case. A sufficient condition to have flexible choice of protection levels is then presented. Simulation results show that the constructed codes can indeed provide codeword bits with different bit-error-rate performance.
This paper presents a novel method for constructing high performance unequal error protection (UEP) quasicyclic low-density parity-check (QC-LDPC) codes. These codes are highly efficient and designed with flexible rates, lengths and number of protection levels. The given QC-LDPC codes are based on the combinatorial design. Each circulant constituting the parity check matrix of the UEP code is determined from subsets with the distinct difference between elements. Simulation results indicate that proposed UEP codes have equivalent performance to UEP codes constructed with the higher girth and lower rate, while achieving superior performance than the codes constructed by conventional equal error protection (EEP) techniques.
In this paper, a new construction of quasi-cyclic low-density parity-check (QC-LDPC) codes for unequal error protection (UEP) is proposed. We first give a new class of UEP block codes. QC-LDPC codes with binomial-term parity-check matrices which can avoid girths less than 8 and achieve an enlarged upper bound on the minimum distance are also introduced. An effective UEP scheme based on the proposed UEP block codes and QC-LDPC codes which can provide flexible choice of protection levels is then presented. Simulation results show that the new QC-LDPC codes can achieve good performance and low error floors. The bits with different designed protection levels can indeed have unequal bit-error-rate performance.
In this correspondence we present a special class of quasi-cyclic low-density parity-check (QC-LDPC) codes, called block-type LDPC (B-LDPC) codes, which have an efficient encoding algorithm due to the simple structure of their parity-check matrices. Since the parity-check matrix of a QC-LDPC code consists of circulant permutation matrices or the zero matrix, the required memory for storing it can be significantly reduced, as compared with randomly constructed LDPC codes. We show that the girth of a QC-LDPC code is upper-bounded by a certain number which is determined by the positions of circulant permutation matrices. The B-LDPC codes are constructed as irregular QC-LDPC codes with parity-check matrices of an almost lower triangular form so that they have an efficient encoding algorithm, good noise threshold, and low error floor. Their encoding complexity is linearly scaled regardless of the size of circulant permutation matrices.
Algebraic constructions of quasi-cyclic (QC) low-density parity-check (LDPC) codes with unequal error protection (UEP) capabilities have recently been proposed, which can provide different error-correcting capabilities for different parts of the coded bits. However, conventional decoding algorithms are not designed for LDPC codes with UEP. In this paper, we propose three decoding schemes for UEP QC-LDPC codes extended from existing scheduling strategies, tailored to the special structures of the parity-check matrices. Simulation results show that the proposed schemes can provide improved error rate performance especially for coded bits on low protection levels. The decoding convergence can also be accelerated, thereby reducing the computational complexity.