scholarly journals Performance Analysis for Cooperative Communication System with QC-LDPC Codes Constructed with Integer Sequences

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Yan Zhang ◽  
Feng-fan Yang ◽  
Weijun Song
Keyword(s):  
Cooperative Communication ◽  
Ldpc Codes ◽  
Ldpc Code ◽  
Parity Check ◽  
Integer Sequences ◽  
Excellent Performance ◽  
Array Codes ◽  
Integer Sequence ◽  
Overall Performance ◽  
Better Than

This paper presents four different integer sequences to construct quasi-cyclic low-density parity-check (QC-LDPC) codes with mathematical theory. The paper introduces the procedure of the coding principle and coding. Four different integer sequences constructing QC-LDPC code are compared with LDPC codes by using PEG algorithm, array codes, and the Mackey codes, respectively. Then, the integer sequence QC-LDPC codes are used in coded cooperative communication. Simulation results show that the integer sequence constructed QC-LDPC codes are effective, and overall performance is better than that of other types of LDPC codes in the coded cooperative communication. The performance of Dayan integer sequence constructed QC-LDPC is the most excellent performance.

A Construction of Non Binary LDPC Codes by Circular Matrices

2014 ◽  
Vol 909 ◽  
pp. 338-341 ◽  
Author(s):  
Sekson Timakul ◽  
Somsak Choomchuay
Keyword(s):  
Bit Error Rate ◽  
Preliminary Investigation ◽  
Ldpc Codes ◽  
Ldpc Code ◽  
Code Rate ◽  
Parity Check ◽  
Parity Check Matrix ◽  
Code Performance ◽  
Check Matrix ◽  
Better Than

In LDPC code, the structure of code's parity check matrix plays the crucial role in code performance. In this paper proposes the preliminary investigation of a designed parity check matrix from Tanner. We modify this technique in to non binary LDPC structure and decoding with FFT-SPA. We take into high code rate application more than 0.8. The result has shown that in bit error rate (BER) compare between non-binary LDPC and binary LDPC. In our results, the performance of non binary LDPC has better than binary LDPC.

scholarly journals A Construction of High Performance Quasicyclic LDPC Codes: A Combinatoric Design Approach

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Muhammad Asif ◽  
Wuyang Zhou ◽  
Muhammad Ajmal ◽  
Zain ul Abiden Akhtar ◽  
Nauman Ali Khan
Keyword(s):  
Iterative Decoding ◽  
High Performance ◽  
Linear Complexity ◽  
Signal To Noise Ratio ◽  
Additive White Gaussian Noise ◽  
Ldpc Codes ◽  
Combinatorial Designs ◽  
Parity Check ◽  
Excellent Performance ◽  
Moderate Length

This correspondence presents a construction of quasicyclic (QC) low-density parity-check (LDPC) codes based on a special type of combinatorial designs known as block disjoint difference families (BDDFs). The proposed construction of QC-LDPC codes gives parity-check matrices with column weight three and Tanner graphs having a girth lower-bounded by 6. The proposed QC-LDPC codes provide an excellent performance with iterative decoding over an additive white Gaussian-noise (AWGN) channel. Performance analysis shows that the proposed short and moderate length QC-LDPC codes perform as well as their competitors in the lower signal-to-noise ratio (SNR) region but outperform in the higher SNR region. Also, the codes constructed are quasicyclic in nature, so the encoding can be done with simple shift-register circuits with linear complexity.

scholarly journals Design of Quasi-Cyclic Low Density Parity Check Decoder Using Optimized Min-Sum Algorithm

2018 ◽  
Vol 7 (03) ◽  
pp. 23781-23784
Author(s):  
Rajarshini Mishra
Keyword(s):  
Variance Estimation ◽  
Cyclic Codes ◽  
Ldpc Codes ◽  
Ldpc Code ◽  
Low Complexity ◽  
Low Density ◽  
Parity Check ◽  
Decoding Algorithm ◽  
Low Density Parity Check ◽  
Xilinx Fpga

Low-density parity-check (LDPC) have been shown to have good error correcting performance approaching Shannon’s limit. Good error correcting performance enables efficient and reliable communication. However, a LDPC code decoding algorithm needs to be executed efficiently to meet cost , time, power and bandwidth requirements of target applications. Quasi-cyclic low-density parity-check (QC-LDPC) codes are an important subclass of LDPC codes that are known as one of the most effective error controlling methods. Quasi cyclic codes are known to possess some degree of regularity. Many important communication standards such as DVB-S2 and 802.16e use these codes. The proposed Optimized Min-Sum decoding algorithm performs very close to the Sum-Product decoding while preserving the main features of the Min-Sum decoding, that is low complexity and independence with respect to noise variance estimation errors.Proposed decoder is well matched for VLSI implementation and will be implemented on Xilinx FPGA family

Enhanced Performances of W/S SAC-OCDMA System Using LDPC Code

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
A. Bouarfa ◽  
M. Kandouci ◽  
S. Bojanic
Keyword(s):  
Bit Error Rate ◽  
Code Division Multiple Access ◽  
Multiple Access ◽  
Ldpc Code ◽  
Two Dimensional ◽  
Parity Check ◽  
Low Density Parity Check ◽  
Spectral Coding ◽  
Code Division Multiple ◽  
Better Than

AbstractIn an incoherent optical code division multiple access (OCDMA) system using amplitude spectral coding (SAC), which exceeds 1.5 Gbps, it is difficult or impossible to make a transmission with a bit error rate better than 10–9. For this, it is necessary to associate an error correction code (ECC) to the SAC-OCDMA system. In this paper, we proposed an architecture of a two-dimensional SAC-OCDMA system (spectral (w) and spatial (s)) using multi-diagonal code (MD) as spreading code and low-density parity check code (LDPC) as ECC. According to the properties of the MD code and the proposed architecture, the phase induced intensity noise is eliminated, which has improved the performance of the system. The theoretically results shows that LDPC/2D-SAC-OCDMA allowing more than 40 users to be multiplexed compared to a non-coded 2D SAC-OCDMA system. This combination allowed us to increase the cardinality of the LDPC/SAC-OCDMA (W/S) system without using an optical hard limiter.

scholarly journals Performance Analysis of Regular and Irregular LDPC Codes on SPIHT Coded Image Data

2020 ◽  
Vol 2 (2) ◽  
pp. 1-5
Author(s):  
Shahnas P
Keyword(s):  
Data Transmission ◽  
Image Data ◽  
Ldpc Codes ◽  
Ldpc Code ◽  
Performance Comparison ◽  
Image Coder ◽  
Overall Performance ◽  
Irregular Ldpc Codes ◽  
Channel Errors ◽  
Spiht Algorithm

The LDPC (Low Density Parity Check Code) has Shown interesting results for transmitting embedded bit streams over noisy communication channels. Performance comparison of regular and irregular LDPC codes with SPIHT coded image is done here. Different Error Sensitive classes of image data are obtained by using SPIHT algorithm as an image coder. Irregular LDPC codes map the more important class of data into a higher degree protection class to provide more protection. Different degree protection classes of an LDPC code improves the overall performance of data transmission against channel errors. Simulation results show the superiority of irregular LDPC over regular LDPC codes.

scholarly journals Constructing High-Rate QC-LDPC Codes with Large-Girth based on Shortened Array Codes

2011 ◽  
Vol 1 (03) ◽  
Author(s):  
Xu Chen ◽  
Francis C. M. Lau
Keyword(s):  
Ldpc Codes ◽  
High Rate ◽  
Minimum Length ◽  
Low Density ◽  
Parity Check ◽  
Error Performance ◽  
Code Construction ◽  
Array Codes ◽  
Low Density Parity Check ◽  
Large Girth

In this paper, we aim at constructing high-rate quasi-cyclic low-density parity-check (QC-LDPC) codes with girth-10 based on shortened array codes. Our first contribution is the derivation of analytic results on the maximum number of columns for shortened array codes of different girths. Then, inspired by the analysis, we propose a code construction method for column-weight-three codes. We further compare the minimum length and the error performance of the column-weight-three codes constructed by the proposed algorithm and those found by the conventional greedy construction algorithm. We show that the proposed method is more effective than the conventional greedy algorithm in the sense that the minimum length of the codes constructed using the proposed method to achieve different code rates is comparative or much shorter than those constructed using the greedy construction.

Modified Bit-Flipping Decoding of Low-Density Parity-Check Codes

2013 ◽  
Vol 710 ◽  
pp. 723-726
Author(s):  
Yuan Hua Liu ◽  
Mei Ling Zhang
Keyword(s):  
High Throughput ◽  
Error Probability ◽  
Ldpc Codes ◽  
Low Complexity ◽  
Low Density ◽  
Parity Check ◽  
Excellent Performance ◽  
Low Density Parity Check ◽  
Lower Complexity ◽  
Parity Check Codes

A novel bit-flipping (BF) algorithm with low complexity for high-throughput decoding of low-density parity-check (LDPC) codes is presented. At each iteration, a novel threshold pattern is used to determine the code bits whether to be flipped or not, and the flipping error probability is effectively decreased. Compared with the weighted BF algorithm and its modifications, the modified BF algorithm has significantly lower complexity and decoding time. Through simulations the proposed BF algorithm is shown to achieve excellent performance and fast convergence speed while maintaining significantly low complexity thus facilitating high-throughput decoding.

scholarly journals Research on LDPC in an OFDM System

2021 ◽  
Vol 2078 (1) ◽  
pp. 012075
Author(s):  
Chong-Yue Shi ◽  
Hui Li ◽  
You-Ling zhou ◽  
Ping Wang ◽  
Qian Li ◽  
...  
Keyword(s):  
Fading Channel ◽  
Rayleigh Fading ◽  
Simulation Analysis ◽  
Ldpc Codes ◽  
Ldpc Code ◽  
Rayleigh Fading Channel ◽  
Code Length ◽  
Ofdm System ◽  
Number Of Iterations ◽  
Better Than

Abstract In this paper, LDPC codes and OFDM technologies are studied, and combines LDPC and OFDM to simulate and verify the performance. The encoding of LDPC and logarithmic domain BP decoding algorithm and the principle of OFDM are introduced. Through MATLAB, the simulation of OFDM-LDPC system in different channel, different code length, different iteration times, LDPC and OFDM-LDPC in the same conditions are compared. Through simulation analysis, we can know that the performance of OFDM-LDPC system will improve with the increase of the code length. When the SNR is small, the number of iterations has little effect on the performance of OFDM-LDPC system. When the SNR is large, the performance of the system will be improved with the increase of the number of iterations. The performance of OFDM-LDPC codes is better than that of LDPC codes. The performance of OFDM-LDPC code is better than LDPC code in multipath Rayleigh fading channel.

scholarly journals Protograph LDPC Code Design For LS-MIMO 1-bit ADC Systems

2021 ◽  
Author(s):  
Thuy Van Nguyen ◽  
Hung Ngoc Dang
Keyword(s):  
Large Scale ◽  
Mimo Systems ◽  
Ldpc Codes ◽  
Ldpc Code ◽  
Code Design ◽  
Parity Check ◽  
Coding Gain ◽  
Research Topics ◽  
Analog To Digital ◽  
New Codes

Recently, two emerging research topics are protograph low-density parity-check (P-LDPC) and large-scale multi-input multi-output (LS-MIMO) with low-resolution analog-to-digital (ADC) converters (LS-MIMO-LOW-ADC). In these directions, many research works have proposed 1-bit ADC as a good candidate for LS-MIMO systems in order to save both transmission power and circuit energy dissipation. However, we observed that previously reported P-LDPC codes might not have good performance for LS-MIMO systems with 1-bit ADC. Hence, we perform a re-design of the P-LDPC codes for the above systems in this paper. The new codes demonstrate a good coding gain from 0:3 dB at rate 1/2 to 0:5 dB at rate 2/3 in different LS-MIMO configurations with 1-bit ADC.

Image Transmission Based on QC-LDPC Codes with Simple Recursive Encoding Form

2014 ◽  
Vol 602-605 ◽  
pp. 3223-3227
Author(s):  
Hua Xu
Keyword(s):  
Information Transfer ◽  
Ldpc Codes ◽  
Ldpc Code ◽  
Image Transmission ◽  
Parity Check ◽  
Extrinsic Information ◽  
Transmission Scheme ◽  
Check Matrix ◽  
Exponent Matrix ◽  
Base Matrix

Low encoding delay and complexity is very important for image transmission. This paper proposes a novel image transmission scheme with low encoding complexity. The proposed scheme is based on quasi-cyclic low density parity check (QC-LDPC) codes with a simple recursive encoding form (SREF QC-LDPC code) which results in low encoding complexity and delay. Constructing the SREF QC-LDPC codes in this scheme composes of two main steps, construction of the base matrix and the exponent matrix. We combine the differential evolution and protograph extrinsic information transfer (PEXIT) method to optimize the base matrix of QC-LDPC code. Consequently, the exponent matrix and the parity check matrix are constructed. Simulation results show that the proposed scheme based on SREF QC-LDPC code can provide a good tradeoff between the performance and complexity.

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