Generalized Low-Density Parity-Check Codes PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download Generalized Low-Density Parity-Check Codes PDF full book. Access full book title Generalized Low-Density Parity-Check Codes by Sherif Elsanadily. Download full books in PDF and EPUB format.
Author: Sherif Elsanadily
Publisher:
ISBN:
Category : Computers
Languages : en
Pages : 0
Get Book Here
Book Description
Scientists have competed to find codes that can be decoded with optimal decoding algorithms. Generalized LDPC codes were found to compare well with such codes. LDPC codes are well treated with both types of decoding; HDD and SDD. On the other hand GLDPC codes iterative decoding, on both AWGN and BSC channels, was not sufficiently investigated in the literature. This chapter first describes its construction then discusses its iterative decoding algorithms on both channels so far. The SISO decoders, of GLDPC component codes, show excellent error performance with moderate and high code rate. However, the complexities of such decoding algorithms are very high. When the HDD BF algorithm presented to LDPC for its simplicity and speed, it was far from the BSC capacity. Therefore involving LDPC codes in optical systems using such algorithms is a wrong choice. GLDPC codes can be introduced as a good alternative of LDPC codes as their performance under BF algorithm can be improved and they would then be a competitive choice for optical communications. This chapter will discuss the iterative HDD algorithms that improve decoding error performance of GLDPC codes. SDD algorithms that maintain the performance but lowering decoding simplicity are also described.
Author: Sherif Elsanadily
Publisher:
ISBN:
Category : Computers
Languages : en
Pages : 0
Get Book Here
Book Description
Scientists have competed to find codes that can be decoded with optimal decoding algorithms. Generalized LDPC codes were found to compare well with such codes. LDPC codes are well treated with both types of decoding; HDD and SDD. On the other hand GLDPC codes iterative decoding, on both AWGN and BSC channels, was not sufficiently investigated in the literature. This chapter first describes its construction then discusses its iterative decoding algorithms on both channels so far. The SISO decoders, of GLDPC component codes, show excellent error performance with moderate and high code rate. However, the complexities of such decoding algorithms are very high. When the HDD BF algorithm presented to LDPC for its simplicity and speed, it was far from the BSC capacity. Therefore involving LDPC codes in optical systems using such algorithms is a wrong choice. GLDPC codes can be introduced as a good alternative of LDPC codes as their performance under BF algorithm can be improved and they would then be a competitive choice for optical communications. This chapter will discuss the iterative HDD algorithms that improve decoding error performance of GLDPC codes. SDD algorithms that maintain the performance but lowering decoding simplicity are also described.
Author: Fang-Chun Kuo
Publisher:
ISBN:
Category :
Languages : en
Pages : 82
Get Book Here
Book Description
Author: Michael Lentmaier
Publisher:
ISBN:
Category :
Languages : en
Pages : 58
Get Book Here
Book Description
Author: Chung-Li Wang
Publisher:
ISBN: 9781124223643
Category :
Languages : en
Pages :
Get Book Here
Book Description
Low-density parity-check (LDPC) codes are currently the most promising coding technique to achieve the Shannon capacities for a wide range of channels. These codes were first discovered by Gallager in 1962 and then rediscovered in late 1990's. Ever since their rediscovery, a great deal of research effort has been expended in design, construction, encoding, decoding, performance analysis, generalizations, and applications of LDPC codes. This research is set up to investigate two major aspects of LDPC codes: weight distributions and code constructions. The research focus of the first part is to analyze the asymptotic weight distributions of various ensembles. Analysis shows that for generalized LDPC (G-LDPC) and doubly generalized LDPC (DG-LDPC) code ensembles with some conditions, the average minimum distance grows linearly with the code length. This implies that both ensembles contain good codes. The effect of changing the component codes of the ensemble on the minimum distance is clarified. The computation of asymptotic weight and stopping set enumerators is improved. Furthermore, the average weight distribution of a multi-edge type code ensemble is investigated to obtain its upper and lower bounds. Based on them, the growth rate of the number of codewords is defined. For the growth rate of codewords with small linear, logarithmic, and constant weights, the approximations are given with two critical coefficients. It is shown that for infinite code length, the properties of the weight distribution are determined by its asymptotic growth rate. The second part of the research emphasizes specific designs and constructions of LDPC codes that not only perform well but can also be efficiently encoded. One such construction is the serial concatenation of an LDPC outer code and an accumulator with an interleaver. Such construction gives a code called an LDPCA code. The study shows that well designed LDPCA codes perform just as well as the regular LDPC codes. It also shows that the asymptotic minimum distance of regular LDPCA codes grows linearly with the code length.
Author: National Aeronautics and Space Adm Nasa
Publisher:
ISBN: 9781723736247
Category :
Languages : en
Pages : 36
Get Book Here
Book Description
Low density parity check (LDPC) codes with iterative decoding based on belief propagation achieve astonishing error performance close to Shannon limit. No algebraic or geometric method for constructing these codes has been reported and they are largely generated by computer search. As a result, encoding of long LDPC codes is in general very complex. This paper presents two classes of high rate LDPC codes whose constructions are based on finite Euclidean and projective geometries, respectively. These classes of codes a.re cyclic and have good constraint parameters and minimum distances. Cyclic structure adows the use of linear feedback shift registers for encoding. These finite geometry LDPC codes achieve very good error performance with either soft-decision iterative decoding based on belief propagation or Gallager's hard-decision bit flipping algorithm. These codes can be punctured or extended to obtain other good LDPC codes. A generalization of these codes is also presented.Kou, Yu and Lin, Shu and Fossorier, MarcGoddard Space Flight CenterEUCLIDEAN GEOMETRY; ALGORITHMS; DECODING; PARITY; ALGEBRA; INFORMATION THEORY; PROJECTIVE GEOMETRY; TWO DIMENSIONAL MODELS; COMPUTERIZED SIMULATION; ERRORS; BLOCK DIAGRAMS...
Author: Yue Min
Publisher:
ISBN:
Category : Coding theory
Languages : en
Pages : 125
Get Book Here
Book Description
Author: Xiaoliang Qi
Publisher: World Scientific
ISBN: 9811231729
Category : Technology & Engineering
Languages : en
Pages : 510
Get Book Here
Book Description
This book honors the remarkable science and life of Shoucheng Zhang, a condensed matter theorist known for his work on topological insulators, the quantum Hall effect, spintronics, superconductivity, and other fields. It contains the contributions displayed at the Shoucheng Zhang Memorial Workshop held on May 2-4, 2019 at Stanford University.
Author:
Publisher:
ISBN:
Category : French language
Languages : en
Pages :
Get Book Here
Book Description
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
Get Book Here
Book Description
In this doctoral dissertation, a construction of binary and nonbinary low-density parity-check (LDPC) codes with quasi-cyclic (QC) structures is presented. First, a general construction of RC-constrained arrays of circulant permutation matrices is introduced, then a specific construction method based on additive subgroups of finite fields is presented. Array masking is also proposed to improve the waterfall-region performance of the QC-LDPC codes, where an algorithm to construct irregular masking matrices is introduced for low error floors. Simulations show that all the above-constructed codes perform well on AWGN channels. Also presented in this dissertation is an LDPC-based error control scheme in a multicast network where a well-known network coding is used. With this scheme, error performance of the system can be improved and equal error protection can be achieved. Finally, an iterative decoding with backtracking is presented. This decoding algorithm greatly lowers the error floors of many regular and irregular LDPC codes of different constructions, and in many cases can push the error floors down to a level limited by the codes' minimum distances. Performance analysis and error floor estimation for the proposed algorithm are also performed.
Author: Marc Fossorier
Publisher: Springer
ISBN: 3540448284
Category : Mathematics
Languages : en
Pages : 275
Get Book Here
Book Description
This book constitutes the refereed proceedings of the 15th International Symposium on Applied Algebra, Algebraic Algorithms and Error-Correcting Codes, AAECC-15, held in Toulouse, France, in May 2003.The 25 revised full papers presented together with 2 invited papers were carefully reviewed and selected from 40 submissions. Among the subjects addressed are block codes; algebra and codes: rings, fields, and AG codes; cryptography; sequences; decoding algorithms; and algebra: constructions in algebra, Galois groups, differential algebra, and polynomials.
