Download or read book Parallel Encoders and Decoders for Low density Parity check Convolutional Codes on the XInC TM Multi threaded Microprocessor written by Xin Sheng Zhou and published by . This book was released on 2008 with total page 177 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Parallel node Low density Parity check Convolutional Code Encoder and Decoder Architectures written by Tyler Brandon and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Architecture for Low density Parity check Convolutional Code Encoders and Decoders written by Ramkrishna Swamy and published by . This book was released on 2007 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book On Low density Parity check Convolutional Codes written by Marcos Bruno Saldanha Tavares and published by Jörg Vogt Verlag. This book was released on 2010 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Power Characterization of a Gbit s Fpga Convolutional Ldpc Decoder written by Si-Yun Li and published by . This book was released on 2012 with total page 101 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis, we present an FPGA implementation of parallel-node low-density-parity-check convolutional-code (PN-LDPC-CC) encoder and decoder. A 2.4 Gbit/s rate-1/2 (3, 6) PN-LDPC-CC encoder and decoder were implemented on an Altera development and education board (DE4). Detailed power measurements of the FPGA board for various configurations of the design have been conducted to characterize the power consumption of the decoder module. For an Eb/N0 of 5 dB, the decoder with 9 processor cores (pipelined decoder iteration stages) has a bit-error-rate performance of 10E-10 and achieves an energy-per-coded-bit of 1.683 nJ based on raw power measurement results. The increase in Eb/N0 can effectively reduce the decoder power and energy-per-coded-bit for configurations with 5 or more processor cores for Eb/N0

Download or read book Flexible Encoder and Decoder Designs for Low density Parity check Codes written by Sunitha Kopparthi and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Future technologies such as cognitive radio require flexible and reliable hardware architectures that can be easily configured and adapted to varying coding parameters. The objective of this work is to develop a flexible hardware encoder and decoder for low-density parity-check (LDPC) codes. The design methodologies used for the implementation of a LDPC encoder and decoder are flexible in terms of parity-check matrix, code rate and code length. All these designs are implemented on a programmable chip and tested. Encoder implementations of LDPC codes are optimized for area due to their high complexity. Such designs usually have relatively low data rate. Two new encoder designs are developed that achieve much higher data rates of up to 844 Mbps while requiring more area for implementation. Using structured LDPC codes decreases the encoding complexity and provides design flexibility. The architecture for an encoder is presented that adheres to the structured LDPC codes defined in the IEEE 802.16e standard. A single encoder design is also developed that accommodates different code lengths and code rates and does not require re-synthesis of the design in order to change the encoding parameters. The flexible encoder design for structured LDPC codes is also implemented on a custom chip. The maximum coded data rate of the structured encoder is up to 844 Mbps and for a given code rate its value is independent of the code length. An LDPC decoder is designed and its design methodology is generic. It is applicable to both structured and any randomly generated LDPC codes. The coded data rate of the decoder increases with the increase in the code length. The number of decoding iterations used for the decoding process plays an important role in determining the decoder performance and latency. This design validates the estimated codeword after every iteration and stops the decoding process when the correct codeword is estimated which saves power consumption. For a given parity-check matrix and signal-to-noise ratio, a procedure to find an optimum value of the maximum number of decoding iterations is presented that considers the affects of power, delay, and error performance.

Download or read book Architectures for Parallel Low Density Parity Check Decoders written by Cristiano Castellano and published by . This book was released on 2005 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Low Complexity Decoding of Low Density Parity Check Codes Through Optimal Quantization and Machine Learning and Optimal Modulation and Coding for Short Block Length Transmissions written by Linfang Wang and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation investigates two topics in channel coding theory: low-complexity decoder design for low-density parity-check (LDPC) codes and reliable communication in the short blocklength regime. For the first topic, we propose a finite-precision decoding method that features the three steps of Reconstruction, Computation, and Quantization (RCQ). The parameters of the RCQ decoder, for both the flooding-scheduled and the layered-scheduled, can be designed efficiently using discrete density evolution featuring hierarchical dynamic quantization (HDQ). To further reduce the hardware usage of the RCQ decoder, we propose a second RCQ framework called weighted RCQ (W-RCQ). Unlike the RCQ decoder, whose quantization and reconstruction parameters change in each layer and iteration, the W-RCQ decoder limits the number of quantization and reconstruction functions to a very small number during the decoding process, for example, three or four. However, the W-RCQ decoder weights check-to-variable node messages using dynamic parameters optimized by a quantized neural network. The proposed W-RCQ decoder uses fewer parameters than the RCQ decoder, thus requiring much fewer resources such as lookup tables. For the second topic, we apply probabilistic amplitude shaping (PAS) to cyclic redundancy check (CRC)-aided tail-biting trellis-coded modulation (TCM). CRC-TCM-PAS produces practical codes for short block lengths on the additive white Gaussian noise (AWGN) channel. In the transmitter, equally likely message bits are encoded by a distribution matcher (DM), generating amplitude symbols with a desired distribution.A CRC is appended to the sequence of amplitude symbols, and this sequence is then encoded and modulated by TCM to produce real-valued channel input signals. We prove that the sign values produced by the TCM are asymptotically equally likely to be positive or negative. The CRC-TCM-PAS scheme can thus generate channel input symbols with a symmetric capacity-approaching probability mass function. We also provide an analytical upper bound on the frame error rate of the CRC-TCM-PAS system over the AWGN channel. This FER upper bound is the objective function for jointly optimizing the CRC and convolutional code. This paper also proposes a multi-composition DM, a collection of multiple constant-composition DMs. The optimized CRC-TCM-PAS systems achieve frame error rates below the random coding union (RCU) bound in AWGN and outperform the short-blocklength PAS systems with various other forward error correction codes.

Download or read book Universal Decoder for Low Density Parity Check Turbo and Convolutional Codes written by Ahmed Refaey Ahmed Hussein and published by . This book was released on 2011 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: De nombreux systèmes de communication sans fil ont adopté les codes turbo et les codes convolutifs comme schéma de codes correcteurs d'erreurs vers l'avant (FEC) pour les données et les canaux généraux. Toutefois, certaines versions proposent les codes LDPC pour la correction d'erreurs en raison de la complexité de l'implémentation des décodeurs turbo et le succès de certains codes LDPC irréguliers dans la réalisation des mêmes performances que les codes turbo les dépassent dans certains cas avec une complexité de décodage plus faible. En fait, les nouvelles versions des standards de ces systèmes travaillent côte à côte dans des dispositifs réels avec les plus anciennes qui sont basées sur les codes turbo et les codes convolutifs. En effet, ces deux familles de codes offrent toutes deux d'excellentes performances en termes de taux d'erreur binaire (TEB). Par conséquent, il semble être une bonne idée d'essayer de les relier de manière à améliorer le transfert de technologie et l'hybridation entre les deux méthodes. Ainsi, la conception efficace de décodeurs universels des codes convolutifs, turbo, et LDPC est critique pour l'avenir de l'implémentation des systèmes sans fil. En outre, un décodeur efficace pour les codes turbo et codes convolutifs est obligatoire pour la mise en oeuvre de ces systèmes sans fil. Cela pourrait se faire par l'élaboration d'un algorithme de décodage unifié des codes convolutifs, turbo et LDPC par des simulations et des études analytiques suivies d'une phase de mise en oeuvre. Pour introduire ce décodeur universel, il existe deux approches, soit sur la base de l'algorithme du maximum a posteriori (MAP) ou l'algorithme de propagation de croyance (BP). D'une part, nous étudions une nouvelle approche pour décoder les codes convolutifs et les turbo codes au moyen du décodeur par propagation de croyances (BP) décodeur utilisé pour les codes de parité à faible densité (codes LDPC). En outre, nous introduisons un système de représentation général pour les codes convolutifs par des matrices de contrôle de parité. De plus, les matrices de contrôle de parité des codes turbo sont obtenus en traitant les codes turbo parallèles comme des codes convolutifs concaténés. En effet, l'algorithme BP fournit une méthodologie très efficace pour la conception générale des algorithmes de décodage itératif de faible complexité pour toutes les classes des codes convolutifs ainsi que les turbo-codes. Alors qu'une petite perte de performance est observée lors du décodage de codes turbo avec BP au lieu du MAP, cela est compensé par la complexité moindre de l'algorithme BP et les avantages inhérents à une architecture unifiée de décodage. En outre, ce travail exploite la représentation tail-biting de la matrice de contrôle de parité des codes convolutifs et des codes turbo, ce qui permet le décodage par un algorithme de propagation de croyance unifiée (BP) pour les nouveaux systèmes de communication sans fils tels que le WiMAX (Worldwide Interoperability for Microwave Access) et le LTE (Long Term Evolution). D'autre part, comme solution alternative, une recherche est effectuée sur la façon de produire un décodeur combiné de ces deux familles de codes basé sur l'algorithme MAP. Malheureusement, cette seconde solution nécessite beaucoup de calculs et de capacité de stockage pour sa mise en oeuvre. En outre, ses récurrences en avant et en arrière résultent en de longs délais de décodage. Entre temps, l'algorithme MAP est basé sur le treillis et la structure en treillis du code LDPC est suffisamment compliquée en raison de la matrice de contrôle de parité de grande taille. En conséquence, cette approche peut être difficile à mettre en oeuvre efficacement car elle nécessite beaucoup de calculs et une grande capacité de stockage. Enfin, pour prédire le seuil de convergence des codes turbo, nous avons appliqué la méthode de transfert d'information extrinsèque (EXIT) pour le décodeur correspondant en le traitant comme une concaténation de noeuds de variable et de contrôle.

Download or read book Convolutional Coding written by L. H. Charles Lee and published by Artech House Communications Li. This book was released on 1997 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt: Table of Contents Preface Ch. 1 Introduction to Coded Digital Communication Systems 1 Ch. 2 Structures of Convolutional Codes 11 Ch. 3 Suboptimal and Optimal Decoding of Convolutional Codes 57 Ch. 4 Sequential Decoding of Convolutional Codes 89 Ch. 5 Encoding and Decoding of Punctured Convolutional Codes 101 Ch. 6 Majority-Logic Decoding of Convolutional Codes 117 Ch. 7 Combined Convolutional Coding and Modulation 149 Ch. 8 Combined Coding, Modulation, and Equalization 209 Ch. 9 Applications of Convolutional Codes 225 App. A Connection Vectors of Convolutional Codes for Viterbi Decoding 245 App. B Connection Vectors of Convolutional Codes for Sequential Decoding 249 App. C Puncturing Matrix for Punctured and Rate-Compatible Punctured Convolutional Codes 251 App. D Generator Polynomials for Self-Orthogonal Systematic Convolutional Codes 263 App. E Generator Polynomial Matrix for Two-Dimensional Linear Trellis Codes 265 App. F Encoder Trellis Program 269 App. G Viterbi Codec Programs 283 About the Author 307 Index 309.

Download or read book Low complexity High speed VLSI Design of Low density Parity check Decoders written by Zhiqiang Cui and published by . This book was released on 2008 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt: Low-Density Parity-check (LDPC) codes have attracted considerable attention due to their capacity approaching performance over AWGN channel and highly parallelizable decoding schemes. They have been considered in a variety of industry standards for the next generation communication systems. In general, LDPC codes achieve outstanding performance with large codeword lengths (e.g., N>1000 bits), which lead to a linear increase of the size of memory for storing all the soft messages in LDPC decoding. In the next generation communication systems, the target data rates range from a few hundred Mbit/sec to several Gbit/sec. To achieve those very high decoding throughput, a large amount of computation units are required, which will significantly increase the hardware cost and power consumption of LDPC decoders. LDPC codes are decoded using iterative decoding algorithms. The decoding latency and power consumption are linearly proportional to the number of decoding iterations. A decoding approach with fast convergence speed is highly desired in practice. This thesis considers various VLSI design issues of LDPC decoder and develops efficient approaches for reducing memory requirement, low complexity implementation, and high speed decoding of LDPC codes. We propose a memory efficient partially parallel decoder architecture suited for quasi-cyclic LDPC (QC-LDPC) codes using Min-Sum decoding algorithm. We develop an efficient architecture for general permutation matrix based LDPC codes. We have explored various approaches to linearly increase the decoding throughput with a small amount of hardware overhead. We develop a multi-Gbit/sec LDPC decoder architecture for QC-LDPC codes and prototype an enhanced partially parallel decoder architecture for a Euclidian geometry based LDPC code on FPGA. We propose an early stopping scheme and an extended layered decoding method to reduce the number of decoding iterations for undecodable and decodable sequence received from channel. We also propose a low-complexity optimized 2-bit decoding approach which requires comparable implementation complexity to weighted bit flipping based algorithms but has much better decoding performance and faster convergence speed.

Download or read book On the Understanding of Protograph based Low Density Parity Check Convolutional Code Design written by Patrick Grosa and published by . This book was released on 2014 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book From LDPC Block to LDPC Convolutional Codes written by Wei Liu and published by . This book was released on 2019 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mots-clés de l'auteur: Belief propagation ; capacity ; capacity-achieving codes ; low-density parity-check block codes and low-density parity-check convolutional codes ; iterative message-passing decoding algorithms ; maximum a posteriori decoding ; maximum likelihood decoding ; stability condition ; threshold saturation ; universality.

Download or read book Low Density Parity Check Decoder Architectures for Integrated Circuits and Quantum Cryptography written by Mario Milicevic and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Forward error correction enables reliable one-way communication over noisy channels, by transmitting redundant data along with the message in order to detect and resolve errors at the receiver. Low-density parity-check (LDPC) codes achieve superior error-correction performance on Gaussian channels under belief propagation decoding, however, their complex parity-check matrix structure introduces hardware implementation challenges. This thesis explores how the quasi-cyclic structure of LDPC parity-check matrices can be exploited in the design of low-power hardware architectures for multi-Gigabit/second decoders realized in CMOS technology, as well as in the design and construction of multi-edge LDPC codes for long-distance (beyond 100km) quantum cryptography over optical fiber. A frame-interleaved architecture is presented with a path-unrolled message-passing schedule to reduce the complexity of routing interconnect in an integrated circuit decoder implementation. A proof-of-concept silicon test chip was fabricated in the 28nm CMOS technology node. The LDPC decoder chip supports the four codes presented in the IEEE 802.11ad standard, occupies an area of 3.41mm^2, and achieves an energy efficiency of 15pJ/bit while delivering a maximum throughput of 6.78Gb/s, and operating with a 202MHz clock at 0.9V supply. The test chip achieves the highest normalized energy efficiency among published CMOS-based decoders for the IEEE 802.11ad standard. A quasi-cyclic code construction technique is applied to a multi-edge LDPC code with block length of 10^6 bits in order to reduce the latency of LDPC decoding in the key reconciliation step of long-distance quantum key distribution. The GPU-based decoder achieves a maximum information throughput of 7.16Kb/s, and extends the current maximum transmission distance from 100km to 160km with a secret key rate of 4.10 x 10^(-7) bits/pulse under 8-dimensional reconciliation. The GPU-based decoder delivers up to 8.03x higher decoded information throughput over the upper bound on secret key rate for a lossy optical channel, thus demonstrating that key reconciliation with LDPC codes is no longer a post-processing bottleneck in quantum key distribution. The contributions presented in this thesis can be applied to future research in the implementation of silicon-based linear-program decoders for high-reliability channels, and single-chip solutions for quantum key distribution containing integrated photonics and post-processing algorithms.

Download or read book Implementation of Decoders for LDPC Block Codes and LDPC Convolutional Codes Based on the Parallel Architecture of the GPUS written by Yue Zhao and published by . This book was released on 2012 with total page 91 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fundamentals Of Convolutional Coding ieee written by R. Johannesson, K.Sh. Zigangirov and published by Universities Press. This book was released on with total page 444 pages. Available in PDF, EPUB and Kindle. Book excerpt: Convlutional codes, among the main error control codes, are routinely used in applications for mobile telephony, satellite communications, and voice-band modems. This book brings you a clear and comprehensive discussion of the basic principles underlying convolutional coding. It is unmatched in the field for its accessible analysis of the structural properties of convolutional encoders.

Download or read book Fundamentals of Convolutional Coding written by Rolf Johannesson and published by . This book was released on 2015 with total page 428 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fundamentals of Convolutional Coding, Second Edition, regarded as a bible of convolutional coding brings you a clear and comprehensive discussion of the basic principles of this field. Two new chapters on low-density parity-check (LDPC) convolutional codes and iterative coding. Viterbi, BCJR, BEAST, list, and sequential decoding of convolutional codes. Distance properties of convolutional codes.