Gallager introduced LDPC codes in 1962, presenting a construction method to randomly allocate bits in a sparse parity-check matrix subject to constraints on the row and column weights. Since then improvements have been made to Gallager’s construction method and some analytic constructions for LDPC codes have recently been presented. However, analytically constructed LDPC codes comprise only a v...

The character of Parallel Concatenated LDPC codes with rate-compatible is analyzed. An Incremental redundancy hybrid ARQ scheme based on parallel concatenated LDPC codes is introduced. We studied the throughput of the new HARQ scheme and obtained the closed_form solutions. Furthermore, the throughput of the new HARQ scheme is simulated. It shows that for arbitrary block fading channel, comprisi...

A constant challenge in Quasi-Cyclic Low-Density Parity-Check (QC-LDPC) codes lies on flexible code lengths and rates, conditioned by good error performance. This paper presents an optimal construction method of QC-LDPC Codes on the basis of graphical model and search algorithm. Utilizing the proposed scheme, we can construct adaptable QC-LDPC codes whose girths are no less than 12, and column ...

Trapping sets have been identified as one of the main factors causing error floors of low-density parity-check (LDPC) codes at high SNR values. By adding several new rows to the original parity-check matrix, a novel method is proposed to eliminate small trapping sets in the LDPC code’s Tanner graph. Based on this parity-check matrix extension, we design new codes with low error floors from the ...

We address the problem of constructing of coding schemes for the channels with high-order modulations. It is known, that non-binary LDPC codes are especially good for such channels and significantly outperform their binary counterparts. Unfortunately, their decoding complexity is still large. In order to reduce the decoding complexity we consider multilevel coding schemes based on non-binary LD...

Binary low-density parity-check (LDPC) codes have recently emerged as a promising alternative to turbo codes and have been shown to achieve excellent coding gains in AWGN channels. Non-binary LDPC codes have demonstrated improved performance over binary LDPC codes but their decoding is computationally intensive. Fourier transform decoding can reduce the decoding complexity but has a number of p...

This paper presents a construction of very high-rate low-density parity-check (LDPC) codes based on the incidence matrices of unital designs. Like the projective geometry and oval designs, unital designs exist with incidence matrices which are significantly rank deficient. Thus high-rate LDPC codes with a large number of linearly dependent parity-check equations can be constructed. The LDPC cod...

In this paper, we present a construction method of non-binary low-density parity-check (LDPC) convolutional codes. Our construction method is an extension of Felström and Zigangirov construction [1] for non-binary LDPC convolutional codes. The rate-compatibility of the non-binary convolutional code is also discussed. The proposed rate-compatible code is designed from one single mother (2,4)-reg...

LDPC codes are state-of-art error correcting codes, included in and the received samples in LDPC-coded systems using M -QAM schemes. physical layer, especially on the forward-error correction code. (FEC) performance. low-density parity check (LDPC) codes can achieve high Using long FECs with short is possible to apply a non-uniform mapping like for example. Low-density parity-check (LDPC) code ...

-Low-density Parity-check (LDPC) code a very promising near-optimal error correction code(ECC), is being widely considered in next generation industry standards. In this paper, two simple iterative low complexity algorithms for decoding LDPC codes have been explained. These algorithms are implemented using real additions only and also not dependent on power spectral density. The survey paper pr...