Download or read book Investigation on Digital Fountain Codes Over Erasure Channels and Additive White Gaussian Noise Channels written by Weizheng Huang and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Exit Charts Based Analysis and Design of Rateless Codes for the Erasure and Gaussian Channels written by Sabaresan Mothi Venkatesan and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Luby Transform Codes were the first class of universal erasure codes introduced to fully realize the concept of scalable and fault0́0tolerant distribution of data over computer networks, also called Digital Fountain. Later Raptor codes, a generalization of the LT codes were introduced to trade off complexity with performance. In this work, we show that an even broader class of codes exists that are near optimal for the erasure channel and that the Raptor codes form a special case. More precisely, Raptorlike codes can be designed based on an iterative (joint) decoding schedule wherein information is transferred between the LT decoder and an outer decoder in an iterative manner. The design of these codes can be formulated as a LP problem using EXIT Charts and density evolution. In our work, we show the existence of codes, other than the Raptor codes, that perform as good as the existing ones. We extend this framework of joint decoding of the component codes to the additive white Gaussian noise channels and introduce the design of Rateless codes for these channels. Under this setting, for asymptotic lengths, it is possible to design codes that work for a class of channels defined by the signal0́0to0́0noise ratio. In our work, we show that good profiles can be designed using density evolution and Gaussian approximation. EXIT charts prove to be an intuitive tool and aid in formulating the code design problem as a LP problem. EXIT charts are not exact because of the inherent approximations. Therefore, we use density evolution to analyze the performance of these codes. In the Gaussian case, we show that for asymptotic lengths, a range of designs of Rateless codes exists to choose from based on the required complexity and the overhead. Moreover, under this framework, we can design incrementally redundant schemes for already existing outer codes to make the communication system more robust to channel noise variations.

Download or read book Design of Fountain Codes with Error Control written by Amrit Kharel and published by . This book was released on 2013 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis is focused on providing unequal error protection (UEP) to two disjoint sources which are communicating to a common destination via a common relay by using distributed LT codes over a binary erasure channel (BEC), and designing fountain codes with error control property by integrating LT codes with turbo codes over a binary input additive white Gaussian noise (BI-AWGN) channel. A simple yet efficient technique for decomposing the RSD into two entirely different degree distributions is developed and presented in this thesis. These two distributions are used to encode data symbols at the sources and the encoded symbols from the sources are selectively XORed at the relay based on a suitable relay operation before the combined codeword is transmitted to the destination. By doing so, it is shown that the UEP can be provided to these sources. The performance of LT codes over the AWGN channel is well studied and presented in this thesis which indicates that these codes have weak error correction ability over the channel. But, errors introduced into individual symbols during the transmission of information over noisy channels need correction by some error correcting codes. Since it is found that LT codes alone are weak at correcting those errors, LT codes are integrated with turbo codes which are good error correcting codes. Therefore, the source data (symbols) are at first turbo encoded and then LT encoded and transmitted over the AWGN channel. When the corrupted encoded symbols are received at receiver, LT decoding is conducted followed by turbo decoding. The overall performance of the integrated system is studied and presented in this thesis, which suggests that the errors left after LT decoding can be corrected to some extent by turbo decoder.

Download or read book Machine Learning and Intelligent Communications written by Mingxiang Guan and published by Springer Nature. This book was released on 2021-01-23 with total page 538 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume constitutes the refereed post-conference proceedings of the 5th International Conference on Machine Learning and Intelligent Communications, MLICOM 2020, held in Shenzhen, China, in September 2020. Due to COVID-19 pandemic the conference was held virtually. The 55 revised full papers were carefully selected from 133 submissions. The papers are organized thematically in intelligent resource ( spectrum, power) allocation schemes; applications of neural network and deep learning; decentralized learning for wireless communication systems; intelligent antennas design and dynamic configuration; intelligent communications; intelligent positioning and navigation systems; smart unmanned vehicular technology; intelligent space and terrestrial integrated networks; machine learning algorithm and Intelligent networks.

Download or read book Trapping Sets in Fountain Codes Over Noisy Channels written by Vivian Lucia Orozco and published by . This book was released on 2009 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fountain codes have demonstrated great results for the binary erasure channel and have already been incorporated into several international standards to recover lost packets at the application layer. These include multimedia broadcast/multicast sessions and digital video broadcasting on global internet-protocol. The rateless property of Fountain codes holds great promise for noisy channels. These are more sophisticated mathematical models representing errors on communications links rather than only erasures. The practical implementation of Fountain codes for these channels, however, is hampered by high decoding cost and delay. In this work we study trapping sets in Fountain codes over noisy channels and their effect on the decoding process. While trapping sets have received much attention for low-density parity-check (LDPC) codes, to our knowledge they have never been fully explored for Fountain codes. Our study takes into account the different code structure and the dynamic nature of Fountain codes. We show that 'error-free' trapping sets exist for Fountain codes. When the decoder is caught in an error-free trapping set it actually has the correct message estimate, but is unable to detect this is the case. Thus, the decoding process continues, increasing the decoding cost and delay for naught. The decoding process for rateless codes consists of one or more decoding attempts. We show that trapping sets may reappear as part of other trapping sets on subsequent decoding attempts or be defeated by the reception of more symbols. Based on our observations we propose early termination methods that use trapping set detection to obtain improvements in realized rate, latency, and decoding cost for Fountain codes.

Download or read book On Coding for Partial Erasure Channels written by Carolyn Mayer and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Error correcting codes have been essential to the technology we use in everyday life in digital storage, wireless communication, barcodes, and much more. Different channel models are used for different types of communication (for example, if information is sent to one person or to many people) and different types of errors. Partial erasure channels were recently introduced to model applications in which some information remains after an erasure event. These remnants of information may be used to increase the chances of successful decoding. We introduce a new partial erasure channel in which partial erasures correspond to individual bit erasures in the binary expansion of a 2 k-ary symbol or p-ary symbols in the expansion of a pk-ary symbol. We show how multilevel coding and multistage decoding may be used on partial erasure channels and investigate cases in which partial erasure channels may be decomposed into simpler channels. Further, we show that partial erasure channels do not always decompose into simple erasure channels, and that when they do, the erasure channels may not be independent. The rest of this work focuses on three areas: fountain codes on partial erasure channels, relay channels with partial erasures, and graph-based codes for distributed storage. We adapt a class of fountain codes for use on partial erasure channels and show an improvement in terms of the number of symbols that must be generated for the successful decoding of such codes. In a relay channel setting, we consider a simple three node system with a sender, receiver, and relay where at least one of the links is a partial erasure channel. When the sender-receiver link is a degraded version of the sender-relay link, we determine the capacity of the channel. We also introduce a biregular hypergraph construction and find locality properties of codes based on these hypergraphs.

Download or read book High Performance Codes for AWGN Erasure and Burst Channels written by Shumei Song and published by . This book was released on 2007 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Non equiprobable Multi level Coding for the Additive White Gaussian Noise Channel with Tikhonov Phase Error written by Li Ni and published by . This book was released on 2005 with total page 85 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Reduced complexity Decoding of Fountain Codes written by Ketai Hu and published by . This book was released on 2006 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Coding and Capacity for Additive White Gaussian Noise Multi User Channels with Feedback written by Lawrence Howard Ozarow and published by . This book was released on 1979 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt: Deterministic coding schemes are presented for the additive white gaussian noise two user multiple access and broadcast channels with noiseless feedback. The error probabilities for these schemes approach zero at a rate which is doubly exponential in block length. Outer bounds on the capacity region are also obtained for both channels. The achievable region obtained for the multiple access channel is shown to coincide with the outer bound, yielding a solution of the capacity region for this problem. While the achievable region for the broadcast channel does not coincide with the outer bound, for all cases except that in which one channel is a physically degraded version of the other, the achievable region lies outside the set of rates achievable in the absence of feedback. This is the first case in which it has been demonstrated that feedback can enlarge the capacity region of broadcast channels. (Author).

Download or read book Detection and Coding Techniques for Partial Response Channels written by Vladimir Dorfman and published by . This book was released on 2003 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Deterministic Feedback Coding Schemes for the Additive White Gaussian Noise Broadcast and Multiple access Channels written by Lawrence Howard Ozarow and published by . This book was released on 1977 with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Investigation of the Error erasure Channel written by Stephen Dobrow and published by . This book was released on 1966 with total page 59 pages. Available in PDF, EPUB and Kindle. Book excerpt: Several approaches are outlined to the general problem of decoding a digital code word which contains both erasures (nulls) and errors (crossovers). A complementary sequence method is discussed which, for the binary case, reduces the errors-plus-erasures case to that of erasures only, for which a systematic decoding procedure exists. A generalization of this method is also outlined which permits a trade-off between the error-correction and erasure-fill-in capabilities. Some techniques for utilizing the properties of certain special classes of codes in decoding a binary error-erasure channel (BEEC) are also presented. (Author).

Download or read book Improving the Left Degree Distribution of Fountain Codes in the Finite length Regime written by Khaled Farouq Hayajneh and published by . This book was released on 2013 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fountain codes were introduced to provide higher reliability, lower complexities, and more scalability for networks such as the Internet. In this thesis, we study Luby- Transform (LT) codes which are the realization of Fountain codes. In the LT codes, a sparse random factor graph is dynamically generated on both the encoder and decoder sides of the communications channel. The graph is generated from an ensemble degree distribution. The LT codes are also known as rateless codes, in the sense that they can generate potentially limitless codeword symbols from original data and self-adjust to channels with different erasure probabilities. LT Codes also have a very low encoding and decoding complexities when comparing with some traditional block codes, e.g., Reed Solomon (RS) codes and Low-Density-Parity-Check (LDPC) codes. Therefore, LT Codes are suitable for many different kinds of applications such as broadcast transmission. LT codes achieve the capacity of the Binary Erasure Channel (BEC) asymptotically and universally. For finite lengths, the search is continued to nd codes closer to the capacity limits at even lower encoding and decoding complexities. Most previous work on single-layer Fountain coding targets the design via the right degree distribution. The left degree distribution of an LT code is left as Poisson to protect the universality. For finite lengths, this is no longer an issue; thus, we focus on the design of better codes for the BEC and noisy channels as well at practical lengths. We propose two encoding schemes for BEC and noisy channels by shaping the left degree distribution. Our left degree shaping provides codes outperforming regular LT code and all other competing schemes in the literature. For instance, at a bit error rate of 10_{-7} and k = 256, our scheme provides a realized rate of 0.6 which is 23.5% higher than Sorensen et al.'s scheme over BEC. In addition, over noisy channels our proposed scheme achieves an improvement of 14% in the released rates at k = 100 and 30 Belief Propagation (BP) iterations.

Download or read book Channel Coding Techniques for Wireless Communications written by K. Deergha Rao and published by Springer Nature. This book was released on 2019-11-22 with total page 484 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book discusses the latest channel coding techniques, MIMO systems, and 5G channel coding evolution. It provides a comprehensive overview of channel coding, covering modern techniques such as turbo codes, low-density parity-check (LDPC) codes, space–time coding, polar codes, LT codes, and Raptor codes as well as the traditional codes such as cyclic codes, BCH, RS codes, and convolutional codes. It also explores MIMO communications, which is an effective method for high-speed or high-reliability wireless communications. It also examines the evolution of 5G channel coding techniques. Each of the 13 chapters features numerous illustrative examples for easy understanding of the coding techniques, and MATLAB-based programs are integrated in the text to enhance readers’ grasp of the underlying theories. Further, PC-based MATLAB m-files for illustrative examples are included for students and researchers involved in advanced and current concepts of coding theory.

Download or read book Channel Codes written by William Ryan and published by Cambridge University Press. This book was released on 2009-09-17 with total page 709 pages. Available in PDF, EPUB and Kindle. Book excerpt: Channel coding lies at the heart of digital communication and data storage, and this detailed introduction describes the core theory as well as decoding algorithms, implementation details, and performance analyses. In this book, Professors Ryan and Lin provide clear information on modern channel codes, including turbo and low-density parity-check (LDPC) codes. They also present detailed coverage of BCH codes, Reed-Solomon codes, convolutional codes, finite geometry codes, and product codes, providing a one-stop resource for both classical and modern coding techniques. Assuming no prior knowledge in the field of channel coding, the opening chapters begin with basic theory to introduce newcomers to the subject. Later chapters then extend to advanced topics such as code ensemble performance analyses and algebraic code design. 250 varied and stimulating end-of-chapter problems are also included to test and enhance learning, making this an essential resource for students and practitioners alike.

Download or read book Turbo Coding Turbo Equalisation and Space Time Coding written by Lajos Hanzo and published by John Wiley & Sons. This book was released on 2011-05-03 with total page 839 pages. Available in PDF, EPUB and Kindle. Book excerpt: Covering the full range of channel codes from the most conventional through to the most advanced, the second edition of Turbo Coding, Turbo Equalisation and Space-Time Coding is a self-contained reference on channel coding for wireless channels. The book commences with a historical perspective on the topic, which leads to two basic component codes, convolutional and block codes. It then moves on to turbo codes which exploit iterative decoding by using algorithms, such as the Maximum-A-Posteriori (MAP), Log-MAP and Soft Output Viterbi Algorithm (SOVA), comparing their performance. It also compares Trellis Coded Modulation (TCM), Turbo Trellis Coded Modulation (TTCM), Bit-Interleaved Coded Modulation (BICM) and Iterative BICM (BICM-ID) under various channel conditions. The horizon of the content is then extended to incorporate topics which have found their way into diverse standard systems. These include space-time block and trellis codes, as well as other Multiple-Input Multiple-Output (MIMO) schemes and near-instantaneously Adaptive Quadrature Amplitude Modulation (AQAM). The book also elaborates on turbo equalisation by providing a detailed portrayal of recent advances in partial response modulation schemes using diverse channel codes. A radically new aspect for this second edition is the discussion of multi-level coding and sphere-packing schemes, Extrinsic Information Transfer (EXIT) charts, as well as an introduction to the family of Generalized Low Density Parity Check codes. This new edition includes recent advances in near-capacity turbo-transceivers as well as new sections on multi-level coding schemes and of Generalized Low Density Parity Check codes Comparatively studies diverse channel coded and turbo detected systems to give all-inclusive information for researchers, engineers and students Details EXIT-chart based irregular transceiver designs Uses rich performance comparisons as well as diverse near-capacity design examples