scholarly journals Performance Analysis of LDPC Decoding Techniques

2021 ◽  
Vol 9 (5) ◽  
pp. 17-26
Author(s):  
Abdel Halim A. Zikry ◽  
Ashraf Y. Hassan ◽  
Wageda I. Shaban ◽  
Sahar F. Abdel-Momen
Keyword(s):  
Channel Coding ◽  
Coding Theory ◽  
Belief Propagation ◽  
Ldpc Codes ◽  
Ldpc Code ◽  
Soft Decision ◽  
Coding Gain ◽  
Ldpc Decoding ◽  
Communications Systems ◽  
Belief Propagation Algorithm

Low density parity checking codes (LDPC) are one of the most important issues in coding theory at present. LDPC-code are a type of linear-block LDPC-codes. Channel coding might be considered as the finest conversant and most potent components of cellular communications systems, that was employed for transmitting errors corrections imposed by noise, fading and interfering. LDPC-codes are advanced coding gain, i.e., new area in coding. the performances of LDPC-code are similar to the Shannon-limiting, this led to the usage of decoding in several applications in digital communications systems, like DVB-S2 and WLAN802.1..This paper aims to know what is LDPC,what its application and introduce encoding algorithms that gives rise to a linear encoding time and also show that the regular and irregular LDPC performance and also introduce different methods for decoding LDPC. I discuss in detail LDPC decoding algorithm: bit flipping algorithm, as a type from hard decision .belief propagation algorithm, sum product algorithm and minimum sum algorithm as examples from soft decision .I expect that at least some students or researchers involved in researching LDPC codes would find this paper helpful.

A BP Decoding Algorithm Based on Nodes Residual for LDPC Codes and its Hardware Implementation

2011 ◽  
Vol 128-129 ◽  
pp. 7-10
Author(s):  
Zhong Xun Wang ◽  
Xing Cheng Wang ◽  
Fang Qiang Zhu
Keyword(s):  
Hardware Implementation ◽  
Belief Propagation ◽  
Dynamic Scheduling ◽  
Ldpc Codes ◽  
Ldpc Code ◽  
Low Complexity ◽  
Decoding Algorithm ◽  
Fast Decoding ◽  
Good For

We researched BP decoding algorithm based on variable-to-check information residual for LDPC code (VC-RBP) in this paper. It is a dynamic scheduling belief propagation using residuals, and has some advantages，such as fast decoding, good performance, and low complexity. It is similar to residual belief propagation (RBP),but has some difference in computing the residual message. This paper further optimized the new algorithm on DSP of TMS320dm6446, and it is good for hardware implementation.

The Research of LDPC Code in Communication System

2012 ◽  
Vol 532-533 ◽  
pp. 1135-1139
Author(s):  
Dan Hu
Keyword(s):  
Communication System ◽  
Channel Coding ◽  
Iterative Decoding ◽  
Storage System ◽  
Ldpc Codes ◽  
Ldpc Code ◽  
Optical Fiber Communication ◽  
Difficult Problem ◽  
Low Density ◽  
Channel Codes

Low-Density Parity-Check(LDPC) codes are a class of channel codes based on matrix encoding and iterative decoding. It has low decoding complexity as well as capacity approaching performance. Until now, the best designed LDPC codes can achieve the performance within only 0.0045dB of the Shannon limit. With the in-depth study, the encoding complexity of LDPC codes is not a difficult problem for application any more. Today, we can see LDPC codes widely used in many practical systems, such as wireless communication system, deep-space communication system, optical-fiber communication system and media storage system. This thesis first introduces the development of channel coding, and then the basic principles and concepts of LDPC codes. The following parts discuss several techniques of LDPC codes, including the construction methods of low-density parity matrix, the iterative decoding algorithms and performance analysis methods. Besides, we propose our opinions and our improved algorithms.

Design of Modified Minsum Decoder of LDPC Code in the Simplified Difference-Domain

2013 ◽  
Vol 385-386 ◽  
pp. 1576-1581
Author(s):  
Zhong Xun Wang ◽  
Xing Long Gao
Keyword(s):  
Belief Propagation ◽  
Additive White Gaussian Noise ◽  
Ldpc Code ◽  
Phase Shift Keying ◽  
Computation Complexity ◽  
Decoding Algorithm ◽  
Ldpc Decoding ◽  
Shift Keying ◽  
Log Domain ◽  
Binary Phase Shift Keying

In this paper, we propose the modified minsum decoding algorithm of LDPC(Low-Density Parity-Check) code in the simplified difference-domain on the basis of detailed analysis of LDPC decoding algorithm in difference-domain. The simulation indicates that the proposed decoding algorithm offers almost no performance degradation compared with the BP(Belief Propagation) decoding algorithm in log-domain and the decoding algorithm in difference-domain and offers better performance than minsum decoding algorithm in log-domain and greatly reduces the computation complexity in AWGN(Additive White Gaussian Noise) channel and under BPSK(Binary Phase Shift Keying) modulation.

scholarly journals A Simple Scheme for Belief Propagation Decoding of BCH and RS Codes in Multimedia Transmissions

2008 ◽  
Vol 2008 ◽  
pp. 1-12 ◽  
Author(s):  
Marco Baldi ◽  
Franco Chiaraluce
Keyword(s):  
Belief Propagation ◽  
Ldpc Codes ◽  
Block Codes ◽  
Soft Decision ◽  
Linear Block Codes ◽  
Rs Codes ◽  
Nonbinary Codes ◽  
Soft Decision Decoding ◽  
Multimedia Transmissions ◽  
A New Technique

Classic linear block codes, like Bose-Chaudhuri-Hocquenghem (BCH) and Reed-Solomon (RS) codes, are widely used in multimedia transmissions, but their soft-decision decoding still represents an open issue. Among the several approaches proposed for this purpose, an important role is played by the iterative belief propagation principle, whose application to low-density parity-check (LDPC) codes permits to approach the channel capacity. In this paper, we elaborate a new technique for decoding classic binary and nonbinary codes through the belief propagation algorithm. We focus on RS codes included in the recent CDMA2000 standard, and compare the proposed technique with the adaptive belief propagation approach, that is able to ensure very good performance but with higher complexity. Moreover, we consider the case of long BCH codes included in the DVB-S2 standard, for which we show that the usage of “pure” LDPC codes would provide better performance.

Design and Implementation of LDPC Encoder / Decoder in the Atmospheric Laser Communication

2014 ◽  
Vol 672-674 ◽  
pp. 883-887
Author(s):  
Li Min Chang ◽  
Qing Wei Dong ◽  
Ye Zhan
Keyword(s):  
Bit Error Rate ◽  
Error Rate ◽  
Belief Propagation ◽  
Ldpc Codes ◽  
Bp Algorithm ◽  
Laser Communication ◽  
Coding Gain ◽  
Paper Briefly ◽  
Design And Implementation ◽  
And Performance

The paper briefly introduces the structure principle and excellent characteristics of protograph LDPC codes and designs the serial encoding circuit based on FPGA. On the basis of the further study of Belief Propagation (BP) algorithm, λ-min algorithm and A - min algorithm, decoder is designed adopting the complexity and performance eclectic mixed decoding algorithm. Meanwhile, it is verified by the simulation. The result shows that coding gain can be up to about 6 to 8 db, if it meets the requirements of 10-5bit error rate.

scholarly journals Performance Analysis of Coherent Atmospheric Optical Communications with Soft-Decision Forward Error Correction

2013 ◽  
Vol 347-350 ◽  
pp. 1856-1859
Author(s):  
Jin Jing Tao ◽  
Jin Nan Zhang ◽  
Yang An Zhang ◽  
Yong Qing Huang ◽  
Xue Guang Yuan ◽  
...  
Keyword(s):  
Forward Error Correction ◽  
Ldpc Codes ◽  
Ldpc Code ◽  
Coherent Detection ◽  
Heterodyne Detection ◽  
Soft Decision ◽  
Power Requirement ◽  
Received Power ◽  
Forward Error ◽  
Atmospheric Channel

Performance of coherent atmospheric optical communication system with heterodyne detection and LDPC codes was evaluated over atmospheric channel attenuations of which are about 20-30 dB/km. To reduce bit error and enhance the system performance LDPC code was implemented in system. Combining coherent detection and LDPC codes could reduce the received power requirement ~4 dBm at the BER of 10-9.

scholarly journals Belief Propagation in Networks of Spiking Neurons

2009 ◽  
Vol 21 (9) ◽  
pp. 2502-2523 ◽  
Author(s):  
Andreas Steimer ◽  
Wolfgang Maass ◽  
Rodney Douglas
Keyword(s):  
Coding Theory ◽  
Numerical Evaluation ◽  
Visual Cues ◽  
Belief Propagation ◽  
Point Of View ◽  
Spiking Neurons ◽  
Factor Graph ◽  
Theoretical Point ◽  
Belief Propagation Algorithm ◽  
Good Agreement

From a theoretical point of view, statistical inference is an attractive model of brain operation. However, it is unclear how to implement these inferential processes in neuronal networks. We offer a solution to this problem by showing in detailed simulations how the belief propagation algorithm on a factor graph can be embedded in a network of spiking neurons. We use pools of spiking neurons as the function nodes of the factor graph. Each pool gathers “messages” in the form of population activities from its input nodes and combines them through its network dynamics. Each of the various output messages to be transmitted over the edges of the graph is computed by a group of readout neurons that feed in their respective destination pools. We use this approach to implement two examples of factor graphs. The first example, drawn from coding theory, models the transmission of signals through an unreliable channel and demonstrates the principles and generality of our network approach. The second, more applied example is of a psychophysical mechanism in which visual cues are used to resolve hypotheses about the interpretation of an object's shape and illumination. These two examples, and also a statistical analysis, demonstrate good agreement between the performance of our networks and the direct numerical evaluation of belief propagation.

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.

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