Download or read book Low density parity check codes for wireless datacast networks written by Kristian Nybom and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Pervasive Mobile and Ambient Wireless Communications written by Roberto Verdone and published by Springer Science & Business Media. This book was released on 2012-01-02 with total page 696 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pervasive Mobile and Ambient Wireless Communications reports the findings of COST 2100, a project of the European intergovernmental COST framework addressing various topics currently emerging in mobile and wireless communications. Drawing on experience developed in this and earlier COST projects, the text represents the final outcome of collaborative work involving more than 500 researchers in 140 institutions and 30 countries (including outside Europe). The book’s subject matter includes: transmission techniques; signal processing; radio channel modelling and measurement; radio network issues; and recent paradigms including ultra-wideband, cooperative, vehicle-to-vehicle and body communications. The research reported comes from a variety of backgrounds: academic, equipment-manufacturing and operational and the information contained in this book will bring the study reported to a wider audience from all those spheres of work. Pervasive Mobile and Ambient Wireless Communications will be of interest to researchers for its cutting-edge analysis and to practitioners for its functional usability.
Download or read book Applications of Low Density Parity Check Codes for Wiretap Channels and Congestion Localization in Networks written by Souvik Dihidar and published by . This book was released on 2006 with total page 98 pages. Available in PDF, EPUB and Kindle. Book excerpt: In Chapter 1, we give an introduction to some conventional Cryptographic protocols. Chapter 2 discusses the BB84 protocol in Quantum key Cryptography. The problem of constructing codes for wiretap channels is considered in Chapter 3. Chapter 4 deals with the problem of congestion localization in networks. Chapter 5 summarizes our work in the problem of localizing link failures in networks.
Download or read book Low Density Parity Check Codes written by Robert G. Gallager and published by MIT Press (MA). This book was released on 1963-09-15 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Construction Decoding and Application of Low density Parity check Codes written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this doctoral dissertation, a construction of binary and nonbinary low-density parity-check (LDPC) codes with quasi-cyclic (QC) structures is presented. First, a general construction of RC-constrained arrays of circulant permutation matrices is introduced, then a specific construction method based on additive subgroups of finite fields is presented. Array masking is also proposed to improve the waterfall-region performance of the QC-LDPC codes, where an algorithm to construct irregular masking matrices is introduced for low error floors. Simulations show that all the above-constructed codes perform well on AWGN channels. Also presented in this dissertation is an LDPC-based error control scheme in a multicast network where a well-known network coding is used. With this scheme, error performance of the system can be improved and equal error protection can be achieved. Finally, an iterative decoding with backtracking is presented. This decoding algorithm greatly lowers the error floors of many regular and irregular LDPC codes of different constructions, and in many cases can push the error floors down to a level limited by the codes' minimum distances. Performance analysis and error floor estimation for the proposed algorithm are also performed.
Download or read book On Constructing Low density Parity check Codes written by Xudong Ma and published by . This book was released on 2007 with total page 125 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis focuses on designing Low-Density Parity-Check (LDPC) codes for forward-error-correction. The target application is real-time multimedia communications over packet networks. We investigate two code design issues, which are important in the target application scenarios, designing LDPC codes with low decoding latency, and constructing capacity-approaching LDPC codes with very low error probabilities. On designing LDPC codes with low decoding latency, we present a framework for optimizing the code parameters so that the decoding can be fulfilled after only a small number of iterative decoding iterations. The brute force approach for such optimization is numerical intractable, because it involves a difficult discrete optimization programming. In this thesis, we show an asymptotic approximation to the number of decoding iterations. Based on this asymptotic approximation, we propose an approximate optimization framework for finding near-optimal code parameters, so that the number of decoding iterations is minimized. The approximate optimization approach is numerically tractable. Numerical results confirm that the proposed optimization approach has excellent numerical properties, and codes with excellent performance in terms of number of decoding iterations can be obtained. Our results show that the numbers of decoding iterations of the codes by the proposed design approach can be as small as one-fifth of the numbers of decoding iterations of some previously well-known codes. The numerical results also show that the proposed asymptotic approximation is generally tight for even non-extremely limiting cases. On constructing capacity-approaching LDPC codes with very low error probabilities, we propose a new LDPC code construction scheme based on 2-lifts. Based on stopping set distribution analysis, we propose design criteria for the resulting codes to have very low error floors. High error floors are the main problems of previously constructed capacity-approaching codes, which prevent them from achieving very low error probabilities. Numerical results confirm that codes with very low error floors can be obtained by the proposed code construction scheme and the design criteria. Compared with the codes by the previous standard construction schemes, which have error floors at the levels of 10−3 to 10−4, the codes by the proposed approach do not have observable error floors at the levels higher than 10−7. The error floors of the codes by the proposed approach are also significantly lower compared with the codes by the previous approaches to constructing codes with low error floors.
Download or read book Low density Parity check Codes for Data Storage and Memory Systems written by Seungjune Jeon and published by . This book was released on 2011 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book High Code Rate Low density Parity check Codes with Guaranteed Minimum Distance and Stopping Weight written by John A. Miller and published by . This book was released on 2003 with total page 422 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Construction of Low Density Parity Check Codes Without Short Cycles written by Lizhi Wu and published by . This book was released on 2003 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: With the rapid expansion of communication networks, there has been an increasing demand for efficient and reliable digital data transmission and storage systems. Many efficient codes have been developed. The LDPC code is one of them. In this thesis, the sum-product algorithm is used in the decoding of LDPC codes. Some schemes for encoding LDPC codes have been studied. In particular, two methods of producing regular H matrices have been attempted that include short cycles of length four with code rates of 0.5, and we present three schemes of finding regular H matrices which do not include short cycles of length four with code rate being 0.5. The effect of short cycles in the bipartite graph of regular LDPC codes has been considered. The simulation results show that the BER performances of regular H matrices that do not include short cycles of length four based on BPSK or 8PSK on AWGN channel is better than those of regular H matrices that include short cycles of length four. In conclusion, in order to obtain good performance with LDPC code, one should design H matrix related to bipartite graph without short cycles.
Download or read book Enhancements to Low Density Parity Check Codes written by Khaled ElMahgoub and published by LAP Lambert Academic Publishing. This book was released on 2010-02 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt: LDPC Codes are considered to be serious competitors to turbo codes in terms of performance and complexity. They are specified by a sparse parity check matrix containing mostly 0s and relatively few 1s. In this book, LDPC codes used in the IEEE 802.16 standard physical layer were studied. Two novel techniques to enhance the performance of such codes are introduced. In the first technique, a novel parity check matrix for LDPC codes over GF(4) is proposed based on the binary parity check matrix used in the IEEE 802.16 standard . The proposed code has proven to outperform the binary code used in the IEEE 802.16 standard over both AWGN and SUI-3 channel model. In the second technique, high rate LDPC code is used, in a concatenated coding structure, as an outer code, with a convolutional code as an inner code. The performance of such a concatenated codes is compared with the commonly used one utilizing Reed-Solomon codes over the standard SUI-3 channel model, and show better performance.
Download or read book Low Density Parity Check Code for Next Generation Communication System written by Mayank Ardeshana and published by LAP Lambert Academic Publishing. This book was released on 2011-12 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: Channel coding provides the means of patterning signals so as to reduce their energy or bandwidth consumption for a given error performance. LDPC codes have been shown to have good error correcting performance which enables efficient and reliable communication. LDPC codes have linear decoding complexity but performance approaching close to shannon capacity with iterative probabilistic decoding algorithm. In this dissertation, the performance of different error correcting code such as convolution, Reed Solomon(RS), hamming, block code are evaluated based on different parameters like code rate, bit error rate (BER), Eb/No, complexity, coding gain and compare with LDPC code. In general, message passing algorithm and the sum-product algorithm are used to decode the message. We showed that logarithmic sum-product algorithm with long block length code reduces multiplication to addition by introducing logarithmic likelihood ratio so that it achieves the highest BER performance among all the decoding algorithms. The astonishing performance combined with proposed modified MS decoding algorithm make these codes very attractive for the next generations digital broadcasting system (ABS - S).
Download or read book Low Density Parity Check Codes written by Gordon McDonald and published by . This book was released on 2006 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Design and Analysis of Low density Parity check Codes for Disk Drives Wireless Modems and the Internet PHD written by Yan Li and published by . This book was released on with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Research on Low density Parity Check Codes written by Tao Tian and published by . This book was released on 2003 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Design of Low density Parity check Codes for Multiple input Multiple output Wireless Systems written by Raymond A. Brown and published by . This book was released on 2009 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Low density Parity Check Codes written by Vijay Nagarajan and published by . This book was released on 2004 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Low density Parity check Codes with Reduced Decoding Complexity written by Benjamin Smith and published by . This book was released on 2007 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents new methods to design low-density parity-check (LDPC) codes with reduced decoding complexity. An accurate measure of iterative decoding complexity is introduced. In conjunction with extrinsic information transfer (EXIT) chart analysis, an efficient optimization program is developed, for which the complexity measure is the objective function, and its utility is demonstrated by designing LDPC codes with reduced decoding complexity. For long block lengths, codes designed by these methods match the performance of threshold-optimized codes, but reduce the decoding complexity by approximately one-third. The performance of LDPC codes is investigated when the decoder is constrained to perform a sub-optimal decoding algorithm. Due to their practical relevance, the focus is on the design of LDPC codes for quantized min-sum decoders. For such a decoder, codes designed for the sum-product algorithm are sub-optimal, and an alternative design strategy is proposed, resulting in gains of more than 0.5 dB.
