scholarly journals Minimum Distance Optimization with Chord Edge Growth for High Girth Non-Binary LDPC Codes

Electronics ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 2161
Author(s):  
Changcai Han ◽  
Hui Li ◽  
Weigang Chen
Keyword(s):  
Minimum Distance ◽  
Signal To Noise Ratio ◽  
High Reliability ◽  
Ldpc Codes ◽  
Full Rank ◽  
Ldpc Code ◽  
Low Complexity ◽  
High Signal ◽  
Rank Condition ◽  
Potential Applications

Short or moderate-length non-binary low-density parity-check (NB-LDPC) codes have the potential applications in future low latency and high-reliability communication thanks to the strong error correction capability and parallel decoding. Because of the existence of the error floor, the NB-LDPC codes usually cannot satisfy very low bit error rate (BER) requirements. In this paper, a low-complexity method is proposed for optimizing the minimum distance of the NB-LDPC code in a progressive chord edge growth manner. Specifically, each chord edge connecting two non-adjacent vertices is added to the Hamiltonian cycle one-by-one. For each newly added chord edge, the configuration of non-zero entries corresponding to the chord edge is determined according to the so-called full rank condition (FRC) of all cycles that are related to the chord edge in the obtained subgraph. With minor modifications to the designed method, it can be used to construct the NB-LDPC codes with an efficient encoding structure. The analysis results show that the method for designing NB-LDPC codes while using progressive chord edge growth has lower complexity than traditional methods. The simulation results show that the proposed method can effectively improve the performance of the NB-LDPC code in the high signal-to-noise ratio (SNR) region. While using the proposed scheme, an NB-LDPC code with a quite low BER can be constructed with extremely low complexity.

A Novel LLR-BP Algorithm for LDPC Codes Based on Taylor Series and Least Squares

2013 ◽  
Vol 462-463 ◽  
pp. 193-197
Author(s):  
Xing Ru Zhang ◽  
Jian Ping Li ◽  
Chao Shi Cai
Keyword(s):  
Least Squares ◽  
Taylor Series ◽  
Belief Propagation ◽  
Signal To Noise Ratio ◽  
Ldpc Codes ◽  
Low Complexity ◽  
Significant Loss ◽  
Bp Algorithm ◽  
High Signal ◽  
Decoding Algorithm

An effective log-likelihood-ratio-based belief propagation (LLR-BP) algorithm is proposed. It can reduce computational complexity of decoding algorithm for Low Density Parity Check (LDPC) codes. By using the Taylor series and least squares, high order multiplication based on the hyperbolic tangent (tanh) rule is converted to a first-order multiplication and addition after simplification. Moreover, all the logarithmic and exponential operations disappear without significant loss of the decoding performance. The simulation results show that the performance of the proposed scheme is similar to the general LLR-BP. In particular, we show that the modified algorithm with low complexity can achieve better BER than the other decoding algorithm in high signal-to-noise ratio region.

scholarly journals A Low-Complexity Ordered Statistics Decoding Algorithm for Short Polar Codes

2019 ◽  
Vol 9 (5) ◽  
pp. 831
Author(s):  
Yusheng Xing ◽  
Guofang Tu
Keyword(s):  
Error Correction ◽  
Error Rate ◽  
Complexity Analysis ◽  
Signal To Noise Ratio ◽  
Low Complexity ◽  
High Signal ◽  
Polar Codes ◽  
Decoding Algorithm ◽  
Low Snr ◽  
Ordered Statistics

In this paper, we propose a low-complexity ordered statistics decoding (OSD) algorithm called threshold-based OSD (TH-OSD) that uses a threshold on the discrepancy of the candidate codewords to speed up the decoding of short polar codes. To determine the threshold, we use the probability distribution of the discrepancy value of the maximal likelihood codeword with a predefined parameter controlling the trade-off between the error correction performance and the decoding complexity. We also derive an upper-bound of the word error rate (WER) for the proposed algorithm. The complexity analysis shows that our algorithm is faster than the conventional successive cancellation (SC) decoding algorithm in mid-to-high signal-to-noise ratio (SNR) situations and much faster than the SC list (SCL) decoding algorithm. Our addition of a list approach to our proposed algorithm further narrows the error correction performance gap between our TH-OSD and OSD. Our simulation results show that, with appropriate thresholds, our proposed algorithm achieves performance close to OSD’s while testing significantly fewer codewords than OSD, especially with low SNR values. Even a small list is sufficient for TH-OSD to match OSD’s error rate in short-code scenarios. The algorithm can be easily extended to longer code lengths.

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.

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

Study on Influence of Array Number to PD Direction Finding Accuracy

2014 ◽  
Vol 494-495 ◽  
pp. 841-844
Author(s):  
Qing Xie ◽  
Feng Liao ◽  
Hai Tao Yang ◽  
Wei Tao Hu
Keyword(s):  
Signal To Noise Ratio ◽  
High Reliability ◽  
Partial Discharge ◽  
Direction Finding ◽  
High Signal ◽  
Array Sensor ◽  
Field Environment ◽  
Ultrasonic Array ◽  
Planar Array ◽  
Array Detection

Transformer partial discharge ultrasonic array detection method is a new method with high signal-to-noise ratio and high reliability. But the influence of array number to the direction finding accuracy needs to be further studied. Simulation of direction finding angle with the 15 kinds of sensor array (-arrangement) under two conditions of the acute azimuth and obtuse azimuth , study of change rule of direction finding accuracy of the different array number, for example of the square planar array sensor, based on an improved MUSIC(Multiple Signal Classification) algorithm. The results show that the direction finding accuracy increases as the array number rises, and The specific error ranges of array sensors of different array number by simulating have some degree of guiding significance in the selection of transformer partial discharge ultrasonic array sensor in the field environment.

scholarly journals A Low-Complexity Pilot-Based Frequency-Domain Channel Estimation for ICI Mitigation in OFDM Systems

Electronics ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1404
Author(s):  
Francisco J. Martín-Vega ◽  
Gerardo Gómez
Keyword(s):  
Channel Estimation ◽  
Frequency Domain ◽  
Signal To Noise Ratio ◽  
Minimum Mean Square Error ◽  
Estimation Method ◽  
Low Complexity ◽  
High Signal ◽  
Ofdm Systems ◽  
Coupling Matrix ◽  
Pilot Pattern

A low-complexity pilot pattern and a frequency-domain channel estimation method for Inter-Carrier Interference (ICI) mitigation is proposed for Orthogonal Frequency Division Multiple Access (OFDM) systems. The proposed method exploits the band structure of the coupling matrix to perform an ICI-free channel estimation in the frequency domain. This ICI-free estimation relies on some conditions imposed over the pilot pattern that simplify the complexity of channel estimation significantly, since its complexity is the same as classical least squares (LS) channel estimation used in low mobility scenarios. Then, the ICI is removed by using a modified version of Minimum Mean Square Error (MMSE) equalization, which reduces the computational complexity considerably. This modified MMSE equalization relies on the sparse and banded structure of the coupling matrix and on a low complexity variant of the Cholesky decomposition, which is named LDLH factorization. It is shown that the proposed method greatly improves the Bit Error Rate (BER) in the high Signal-to-Noise Ratio (SNR) regime.

scholarly journals Impact of Co-Channel Interference on Two-Way Relaying Networks with Maximal Ratio Transmission

Electronics ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 392 ◽  
Author(s):  
Awfa Aladwani ◽  
Eylem Erdogan ◽  
Tansal Gucluoglu
Keyword(s):  
Signal To Noise Ratio ◽  
High Reliability ◽  
Symbol Error Rate ◽  
High Signal ◽  
Amplify And Forward ◽  
Estimation Errors ◽  
Channel Interference ◽  
Noise Ratio ◽  
The Impact ◽  
Ratio Transmission

Amplify-and-forward (AF) two-way relay networks (TWRNs) have become popular to provide spectrally efficient communication when range extension or energy efficiency is needed by utilizing a simple relay. However, their performance can be significantly degraded in practice due to co-channel interference (CCI) which is increasing due to growing number of wireless devices and recent cognitive and non-orthogonal multiple access techniques. With the motivation of improving the performance of AF-TWRNs, the use of maximal ratio transmission (MRT) is investigated to achieve high reliability while requiring low receiver complexity for the relay. First, the signal-to-interference-plus-noise ratio (SINR) expression is formulated and upper bounded. Then, tight lower bound expressions of outage probability (OP), sum symbol error rate (SSER), and upper bound ergodic sum rate (ESR) for each source and for the overall system are obtained. Besides, array and diversity gains are provided after deriving the asymptotic expressions of OP and SSER at high signal-to-noise ratio (SNR). Furthermore, the impact of channel estimation errors on the performance is also included. Finally, Monte Carlo simulation results which corroborate our theoretical findings are illustrated.

Low-Cost Teleoperation of Remotely Located Actuators Based on Dual Tone Multi-Frequency Data Transfer

2011 ◽  
Vol 403-408 ◽  
pp. 4727-4734
Author(s):  
Sahil Thakkar ◽  
Animesh Garg ◽  
Adesh Midha ◽  
Prerna Gaur
Keyword(s):  
Cell Phone ◽  
Data Transfer ◽  
Signal To Noise Ratio ◽  
High Reliability ◽  
Low Cost ◽  
Control Unit ◽  
Industrial Applications ◽  
High Signal ◽  
Voice Call ◽  
Car Security

DTMF (Dual Tone Multi Frequency) is a system of signal tones used for telecommunications. DTMF uses two tones to represent each key on the touch pad. DTMF data transfer technique has advantages such as high reliability, constant speed, and high signal to noise ratio, low cost and optimal utilization of existing resources. These features make DTMF an attractive Data Transfer Technique. It finds application in home and car security systems, robot control, SMS and voice call controlled industrial applications. In this paper, we discuss the use of DTMF data transfer in a voice call to control a toy car. Cell phone 1(CP 1), which is at user end, makes a call to cell phone 2(CP 2) at the machine end and establishes a connection. A key is pressed at the user side. Two tones corresponding to one key are encoded and sent through the cell phone network. Both tones are tapped through the earphone jack of cell phone at machine end and are decoded. The output is fed to a Micro-controller. The Micro-controller is connected to the remote control unit of the toy car, which in turn controls the motion of the car. The car moves in various directions according to the key pressed user. The electronic circuit is divided into 2 parts. The transmitter side consisting of Cell phone 1 with an inbuilt encoder and the receiver side consisting of Cell Phone 2, 8870 DTMF decoder and Atmega 16 micro-controller. The programming has been carried out on AVR Bascom®.

Combined Coding Algorithm of LDPC Codes in Bit-Patterned Media Recording Channels

2014 ◽  
Vol 979 ◽  
pp. 70-74
Author(s):  
Chutima Prasartkaew ◽  
Piya Kovintavewat ◽  
Somsak Choomchuay
Keyword(s):  
Random Number ◽  
Signal To Noise Ratio ◽  
Ldpc Codes ◽  
Block Codes ◽  
High Signal ◽  
Bit Patterned Media ◽  
Magic Square ◽  
Patterned Media ◽  
Recording Channels ◽  
Random Number Table

This paper presents a new coding algorithm of irregular low-density parity-check (LDPC) codes. This algorithm consists of two parts of block codes; parity bits was encoded using the magic square based algorithm (MSBA) which suitable for the short block (less than 500 bits) and the data bits, the rest part of all block codes, was encoded using the random number table. This proposed coding algorithm is called ‘Combined Coding Algorithm LDPC codes (CCA-LDPC codes)’ which can be used in bit-patterned media recording (BPMR) channels. The performance of the constructed codes was numerically simulated in BPMR channels model. The obtained performance of the proposed codes was compared with the comparable existing codes. The simulation results show that, at a block length of 4110 bit and code rate of 0.9, the proposed CCA-LDPC codes yields better performance than the existing ones, especially at high signal-to-noise ratio scenario.

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