abstract spacing between check dams depends on the stream bed slope, effective height of check dams and slope of deposited sediments behind the check dams. the slope of deposited sediments is more important than the other two factors because of complications in the way of its occurrence and its measurement after several years of dam construction. this research presents the effective factors aff...

A particular class of low-density parity-check codes referred to as cylinder-type BC-LDPC codes is proposed by Gholami and Eesmaeili. In this paper We represent a double cylinder-type parity-check matrix H by a graph called the block-structure graph of H and denoted by BSG(H). Using the properties of BSG(H) we propose some mother matrices with column-weight two such that the rate of correspondi...

This article explains the design and implementation of both regular and irregular LDPC codes as carried out by me at the Institute of Communications Engineering, Technical University of Munich. The design of a good irregular LDPC code needs a pair of distributions to be specified. This article discusses a randomized construction which attempts to form a parity check matrix whose row and coloumn...

This paper presents a combinatorial construction of low-density parity-check (LDPC) codes from difference covering arrays. While the original construction by Gallagher was by randomly allocating bits in a sparse parity-check matrix, over the past 20 years researchers have used a variety of more structured approaches to construct these codes, with the more recent constructions of well-structured...

A novel method guaranteeing nondecreasing girth is presented for constructing longer low-density parity-check (LDPC) codes from shorter ones. The parity-check matrix of a shorter base code is decomposed into N (N ≥ 2) nonoverlapping components with the same size. Then, these components are combined together to form the parity-check matrix of a longer code, according to a given N×N Latin square....

In this paper, we investigate an efficient encoding approach for generalized low-density (GLD) parity check codes, a generalization of Gallager’s low-density parity check (LDPC) codes. We propose a systematic approach to construct approximate upper triangular GLD parity check matrix which defines a class of efficientencoding GLD codes. It’s shown that such GLD codes have equally good performanc...

Performance of low-density parity-check (LDPC) codes with maximum likelihood decoding (MLD) for solid burst erasures is discussed. The columns of the paritycheck matrix of LDPC codes are permuted to increase the distance between elements (DBEs) which are defined as a number of symbol positions between elements 1 at each row of the parity-check matrix. The column permutation method can change th...

1) Introduction Iterative decoding offers a practical way for implementing LDPC codes. LDPC code is defined by a sparse MxN parity check matrix H that has 0 entries everywhere except for t c 1’s in each column and t r 1’s in each row, where t c and t r are small numbers and they degrees. Irregular LDPC codes have varying number of t c and t r . An LDPC code can be represented by bipartite graph...

In this paper we propose the construction of Spatially Coupled Low-Density Parity-Check (SC-LDPC) codes using a Quasi-Cyclic (QC) algorithm. The QC based approach is optimized to obtain memory efficiency in storing the parity-check matrix in the decoders. A hardware model of the parity-check storage units has been designed for Xilinx FPGA to compare the logic and memory requirements for various...

The concepts of pseudocodeword and pseudoweight play a fundamental role in the finitelength analysis of LDPC codes. The pseudoredundancy of a binary linear code is defined as the minimum number of rows in a parity-check matrix such that the corresponding minimum pseudoweight equals its minimum Hamming distance. By using the value assignment of Chen and Kløve we present new results on the pseudo...