Reliability-based Coded Modulation for Low-density Parity-check Codes [microform] PDF Download
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Author: Robert D. Maddock
Publisher: Library and Archives Canada = Bibliothèque et Archives Canada
ISBN: 9780612974241
Category : Coding theory
Languages : en
Pages : 170
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Book Description
![Reliability-based Coded Modulation for Low-density Parity-check Codes [microform] PDF](https://books.google.com/books/content/images/frontcover/BHoFywAACAAJ?fife=w80-h100)
Author: Robert D. Maddock
Publisher: Library and Archives Canada = Bibliothèque et Archives Canada
ISBN: 9780612974241
Category : Coding theory
Languages : en
Pages : 170
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Author: Lei Zhang
Publisher:
ISBN: 9780494766071
Category :
Languages : en
Pages : 184
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Book Description
A method for designing low-density parity-check (LDPC) codes for bandwidth-efficient high-order coded modulation is proposed. Code structure utilizes the multi-edge-type LDPC code ensemble to achieve an improved match between codeword bit protection capabilities and modulation bit-channel capacities over existing LDPC coded modulation techniques. The multi-dimensional EXIT vector field for the specific multi-edge parameterization is developed for the analysis and design of code ensembles. A multi-dimensional EXIT decoding convergence condition is derived to enable efficient optimization. Code design results in terms of ensemble thresholds and finite-length Monte-Carlo simulations indicate that the new technique improves on the state-of-the-art performance, with sig- nificantly lower design and implementation complexity.
Author: Ravi Narayanaswami
Publisher:
ISBN:
Category :
Languages : en
Pages : 162
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Author: Deepak Sridhara
Publisher:
ISBN:
Category :
Languages : en
Pages : 364
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Author: Jilei Hou
Publisher:
ISBN:
Category :
Languages : en
Pages : 316
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Author: Linfang Wang
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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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.
Author: Hanqing Lou
Publisher:
ISBN: 9780542720406
Category : Code generators
Languages : en
Pages :
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Book Description
In the last decade, helped by the increase in computing power, capacity approaching codes, such as turbo codes and low-density parity check (LDPC) codes, have been proposed. The common characteristics of these codes are their long length and their random-like codeword structure. However, the decoding complexity of turbo codes and the encoding complexity of LDPC codes are substantial. In order to alleviate this problem, we propose the use of low-density generator matrix (LDGM) codes, which are a special class of LDPC codes with low encoding and decoding complexity. In this work, we explore different avenues to successfully apply LDGM codes in different communications environments such as quantum systems, realistic wireless channels with memory, and MIMO channels. In order to do so, it is necessary to generate LDGM codes for different rates. Thus, the first contribution of our work is showing that LDGM codes are very flexible and can be easily modified to achieve different rates. Then, we investigate the following topics: (1) In quantum environments, stabilizer codes are a special yet large class of quantum error-correcting codes, which introduce a connection between classical block codes and quantum codes. (2) We have proposed a modified algorithm for decoding of LDGM codes over hidden Markov channels. The proposed scheme clearly outperforms the system in which the channel statistics are not exploited at the decoder side. (3) In order to approach the capacity limit in MIMO systems, powerful channel codes have to be utilized. We compare schemes based on (i) the concatenation of space-time codes and powerful channel codes and (ii) systems based on just using channel coding (no space-time code) in the context of bit-interleaved coded modulation with an iterative process between the demapper and the code. (4) We compare different transmission schemes for multiple antenna transmission systems based on multilevel codes (MLC) in terms of the maximum rate that they can achieve. We introduce a new architecture that can provide nearly optimum performance without iterative demapping and has lower complexity than the full multilevel coding scheme. (5) We focus on the design of layered transmission schemes that can approach outage capacity in quasi-static fading channels in the high spectral efficiency regime without demapper iterations. (Abstract shortened by UMI.).
Author: Ahmed Attia Abotabl
Publisher:
ISBN:
Category : Coding theory
Languages : en
Pages :
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During the last several decades, information theory has made significant advances in the analysis of the limits of communication in multi-node networks and the methods that can approach those limits. This dissertation studies new multi-level architectures for coded modulation in multi-node networks that aim to approach, in the practical realm, the capacity limits unveiled by information theory. For the two-user additive white Gaussian noise (AWGN) broadcast channel, a multi-level coding architecture is proposed whose performance can approach the entire capacity region, and whose attractive features include a convenient partition of the two users’ data so that one and only one of the modulation bit levels (and the corresponding encoder) must contend with both users’ data. Practical aspects of the problem, including allocation of levels to users and finding level-wise code rates, have been addressed. For the full-duplex decode-forward relay channel, a pragmatic yet capacity-approaching construction is proposed that synthesizes the components of full-duplex transmission via distinct signal levels of a multi-level code at the source and at the relay. The rate penalty due to linearity of component codes is analyzed and to avoid it, a solution is proposed involving the labeling of signal constellations. Simulations show that the proposed architecture together with good point-to-point codes can achieve excellent performance. For the full-duplex decode-compress-forward relay channel, a multi-level coding architecture is proposed and analyzed that achieves rates very close to the best known (information theoretic) achievable rates. The performance of the proposed architecture is evaluated using a combination of low-density parity-check (LDPC) codes and polar codes. For the design of coded modulation for the discrete-input, Gaussian noise wiretap channels, a rate splitting method is proposed to allow a convenient construction of wiretap channel codes via a combination of two separate encoders operating on the data and the dither components. This technique leads naturally to the construction of multilevel codes for the AWGN wiretap channel where the message and the dither are encoded through separate levels without compromising secrecy. The effect of maximum likelihood decoding and multistage decoding at the legitimate receiver, as well as the effect of modulation labeling, are studied.
Author: Yaniv Nana
Publisher:
ISBN:
Category : Coding theory
Languages : en
Pages : 68
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Book Description
Author: Rolando Antonio Carrasco
Publisher: John Wiley & Sons
ISBN: 047074040X
Category : Technology & Engineering
Languages : en
Pages : 322
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Book Description
Comprehensive introduction to non-binary error-correction coding techniques Non-Binary Error Control Coding for Wireless Communication and Data Storage explores non-binary coding schemes that have been developed to provide an alternative to the Reed – Solomon codes, which are expected to become unsuitable for use in future data storage and communication devices as the demand for higher data rates increases. This book will look at the other significant non-binary coding schemes, including non-binary block and ring trellis-coded modulation (TCM) codes that perform well in fading conditions without any expansion in bandwidth use, and algebraic-geometric codes which are an extension of Reed-Solomon codes but with better parameters. Key Features: Comprehensive and self-contained reference to non-binary error control coding starting from binary codes and progressing up to the latest non-binary codes Explains the design and construction of good non-binary codes with descriptions of efficient non-binary decoding algorithms with applications for wireless communication and high-density data storage Discusses the application to specific cellular and wireless channels, and also magnetic storage channels that model the reading of data from the magnetic disc of a hard drive. Includes detailed worked examples for each coding scheme to supplement the concepts described in this book Focuses on the encoding, decoding and performance of both block and convolutional non-binary codes, and covers the Kötter-Vardy algorithm and Non-binary LDPC codes This book will be an excellent reference for researchers in the wireless communication and data storage communities, as well as development/research engineers in telecoms and storage companies. Postgraduate students in these fields will also find this book of interest.
