The Experts below are selected from a list of 5538 Experts worldwide ranked by ideXlab platform
Linnan Lee - One of the best experts on this subject based on the ideXlab platform.
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an innovative low density parity check code design with near Shannon Limit performance and simple implementation
IEEE Transactions on Communications, 2006Co-Authors: M Eroz, Fengwen Sun, Linnan LeeAbstract:A novel parity-check matrix design for low-density parity-check (LDPC) codes is described. By eliminating the routing problem associated with LDPC codes, the design results in a small implementation area, and the codes have outstanding error-rate performance close to the Shannon Limit for a wide range of code rates, from 1/4 to 9/10, and for various modulation schemes such as binary phase-shift keying (PSK), quaternary PSK, 8-PSK, 16-amplitude PSK (APSK), and 32-APSK. As a result, LDPC codes designed with this method have been standardized for next-generation digital video broadcasting.
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dvb s2 low density parity check codes with near Shannon Limit performance
International Journal of Satellite Communications and Networking, 2004Co-Authors: M Eroz, Fengwen Sun, Linnan LeeAbstract:Low density parity check (LDPC) codes are chosen for the second generation digital video broadcasting (DVB) standard. In this paper, we review LDPC codes in general, present belief propagation decoding algorithm in simple terms, describe the standardized LDPC codes and show their performance. Copyright © 2004 John Wiley & Sons, Ltd.
Kohichi Sakaniwa - One of the best experts on this subject based on the ideXlab platform.
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spatially coupled binary mackay neal codes for channels with non binary inputs and affine subspace outputs
International Symposium on Information Theory, 2012Co-Authors: Kenta Kasai, Takayuki Nozaki, Kohichi SakaniwaAbstract:We study LDPC codes for the channel with 2m-ary input x ∊ Fm and output y = x + z ∊ F 2 m. The receiver knows a subspace V ⊂ F 2 m from which z = y − x is uniformly chosen. Or equivalently, the receiver receives an affine subspace y-V where x lies. We consider a joint iterative decoder involving the channel detector and the LDPC decoder. The decoding system considered in this paper can be viewed as a simplified model of the joint iterative decoder over non-binary modulated signal inputs e.g., 2m-QAM. We evaluate the performance of binary spatially-coupled MacKay-Neal codes by density evolution. The iterative decoding threshold is seriously degraded by increasing m. EXIT-like function curve calculations reveal that this degradation is caused by wiggles and can be mitigated by increasing the randomized window size. The resultant iterative decoding threshold values are very close to the Shannon Limit.
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spatially coupled binary mackay neal codes for channels with non binary inputs and affine subspace outputs
arXiv: Information Theory, 2012Co-Authors: Kenta Kasai, Takayuki Nozaki, Kohichi SakaniwaAbstract:We study LDPC codes for the channel with $2^m$-ary input $\underline{x}\in \mathbb{F}_2^m$ and output $\underline{y}=\underline{x}+\underline{z}\in \mathbb{F}_2^m$. The receiver knows a subspace $V\subset \mathbb{F}_2^m$ from which $\underline{z}=\underline{y}-\underline{x}$ is uniformly chosen. Or equivalently, the receiver receives an affine subspace $\underline{y}-V$ where $\underline{x}$ lies. We consider a joint iterative decoder involving the channel detector and the LDPC decoder. The decoding system considered in this paper can be viewed as a simplified model of the joint iterative decoder over non-binary modulated signal inputs e.g., $2^m$-QAM. We evaluate the performance of binary spatially-coupled MacKay-Neal codes by density evolution. The iterative decoding threshold is seriously degraded by increasing $m$. EXIT-like function curve calculations reveal that this degradation is caused by wiggles and can be mitigated by increasing the randomized window size. The resultant iterative decoding threshold values are very close to the Shannon Limit.
David J C Mackay - One of the best experts on this subject based on the ideXlab platform.
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low density parity check codes over gf q
Information Theory Workshop, 1998Co-Authors: Matthew C Davey, David J C MackayAbstract:Binary low density parity check (LDPC) codes have been shown to have near Shannon Limit performance when decoded using a probabilistic decoding algorithm. The analogous codes defined over finite fields GF(q) of order q>2 show significantly improved performance. We present the results of Monte Carlo simulations of the decoding of infinite LDPC codes which can be used to obtain good constructions for finite codes. We also present empirical results for the Gaussian channel including a rate 1/4 code with bit error probability of 10/sup -4/ at E/sub b//N/sub 0/=-0.05 dB.
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low density parity check codes over gf q
IEEE Communications Letters, 1998Co-Authors: Matthew C Davey, David J C MackayAbstract:Gallager's (1962) low-density binary parity check codes have been shown to have near-Shannon Limit performance when decoded using a probabilistic decoding algorithm. We report the empirical results of error-correction using the analogous codes over GF(q) for q>2, with binary symmetric channels and binary Gaussian channels. We find a significant improvement over the performance of the binary codes, including a rate 1/4 code with bit error probability <10/sup -5/ at E/sub b//N/sub 0/=0.2 dB.
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near Shannon Limit performance of low density parity check codes
Electronics Letters, 1996Co-Authors: David J C Mackay, Radford M NealAbstract:The authors report the empirical performance of Gallager's low density parity check codes on Gaussian channels. They show that performance substantially better than that of standard convolutional and concatenated codes can be achieved; indeed the performance is almost as close to the Shannon Limit as that of turbo codes.
Fabian Steiner - One of the best experts on this subject based on the ideXlab platform.
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divergence optimal fixed to fixed length distribution matching with shell mapping
IEEE Wireless Communications Letters, 2019Co-Authors: Patrick Schulte, Fabian SteinerAbstract:Distribution matching (DM) transforms independent and Bernoulli(1/2) distributed bits into a sequence of output symbols with a desired distribution. A fixed-to-fixed length, invertible DM architecture based on shell mapping (SM) is presented. It is shown that SM for DM (SMDM) is the optimum DM for the informational divergence metric and that finding energy optimal sequences is a special case of divergence minimization. Additionally, it is shown how to find the required SM weight function to approximate arbitrary output distributions. SMDM is combined with probabilistic amplitude shaping to operate close to the Shannon Limit. SMDM exhibits excellent performance for short blocklengths as required by ultra-reliable low-latency applications. SMDM outperforms constant composition DM by 0.7 dB when used with 64-QAM at a spectral efficiency of 3 bits/channel use and a 5G low-density parity-check code with a short blocklength of 192 bits.
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divergence optimal fixed to fixed length distribution matching with shell mapping
arXiv: Information Theory, 2018Co-Authors: Patrick Schulte, Fabian SteinerAbstract:Distribution matching (DM) transforms independent and Bernoulli(1/2) distributed bits into a sequence of output symbols with a desired distribution. A fixed-to-fixed length, invertible DM architecture based on shell mapping is presented. It is shown that shell mapping for distribution matching (SMDM) is the optimum DM for the informational divergence metric and that finding energy optimal sequences is a special case of divergence minimization. Additionally, it is shown how to find the required shell mapping weight function to approximate arbitrary output distributions. SMDM is combined with probabilistic amplitude shaping (PAS) to operate close to the Shannon Limit. SMDM exhibits excellent performance for short blocklengths as required by ultra-reliable low-latency (URLLC) applications. SMDM outperforms constant composition DM (CCDM) by 0.6 dB when used with 64-QAM at a spectral efficiency of 3 bits/channel use and a 5G low-density parity-check code with a short blocklength of 192 bits
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rate adaptation and reach increase by probabilistically shaped 64 qam an experimental demonstration
Journal of Lightwave Technology, 2016Co-Authors: Fred Buchali, Fabian Steiner, Georg Bocherer, Laurent Schmalen, Patrick Schulte, W IdlerAbstract:A transmission system with adjustable data rate for single-carrier coherent optical transmission is proposed, which enables high-speed transmission close to the Shannon Limit. The proposed system is based on probabilistically shaped 64-QAM modulation formats. Adjustable shaping is combined with a fixed-QAM modulation and a fixed forward-error correction code to realize a system with adjustable net data rate that can operate over a large reach range. At the transmitter, an adjustable distribution matcher performs the shaping. At the receiver, an inverse distribution matcher is used. Probabilistic shaping is implemented into a coherent optical transmission system for 64-QAM at 32 Gbaud to realize adjustable operation modes for net data rates ranging from 200 to 300 Gb/s. It is experimentally demonstrated that the optical transmission of probabilistically shaped 64-QAM signals outperforms the transmission reach of regular 16-QAM and regular 64-QAM signals by more than 40% in the transmission reach.
Sergei K Turitsyn - One of the best experts on this subject based on the ideXlab platform.
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the impact of phase conjugation on the nonlinear Shannon Limit the difference between optical and electrical phase conjugation
Photonics Society Summer Topical Meeting Series, 2015Co-Authors: A D Ellis, Son Thai Le, Sergei K Turitsyn, Mohammad A Z Alkhateeb, Gabriele Liga, Domanic Lavery, Tianhua Xu, P BayvelAbstract:We show that optical and electrical phase conjugation enable effective nonlinear compensation, The impact of polarization mode dispersion and finite processing bandwidth on the ultimate Limits are also considered.
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nonlinear signal transformations path to capacity above the linear awgn Shannon Limit
Photonics Society Summer Topical Meeting Series, 2014Co-Authors: Mariia Sorokina, Sergei K TuritsynAbstract:We present a methodology for simultaneous optimization of modulation format and regenerative transformations in nonlinear communication channels. We derived analytically the maximum regenerative Shannon capacity, towards which any regenerative channel tends at high SNR and large number of regenerators.
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Regeneration Limit of classical Shannon capacity
Nature communications, 2014Co-Authors: Mariia Sorokina, Sergei K TuritsynAbstract:Since Shannon derived the seminal formula for the capacity of the additive linear white Gaussian noise channel, it has commonly been interpreted as the ultimate Limit of error-free information transmission rate. However, the capacity above the corresponding linear channel Limit can be achieved when noise is suppressed using nonlinear elements; that is, the regenerative function not available in linear systems. Regeneration is a fundamental concept that extends from biology to optical communications. All-optical regeneration of coherent signal has attracted particular attention. Surprisingly, the quantitative impact of regeneration on the Shannon capacity has remained unstudied. Here we propose a new method of designing regenerative transmission systems with capacity that is higher than the corresponding linear channel, and illustrate it by proposing application of the Fourier transform for efficient regeneration of multilevel multidimensional signals. The regenerative Shannon Limit -the upper bound of regeneration efficiency -is derived.
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Exceeding the nonlinear-Shannon Limit using Raman laser based amplification and optical phase conjugation
Conference on Optical Fiber Communication, Technical Digest Series, 2014Co-Authors: I. D. Phillips, Mingming Tan, M. E. McCarthy, Sara Fabbri, Thavamaran Kanesan, Son Thai Le, Elias Giacoumidis, Stylianos Sygletos, N.j. Doran, Sergei K Turitsyn, Paul Harper, Pawel Rosa, A D EllisAbstract:We demonstrate that a combination of Raman laser based amplification and optical phase conjugation enables transmission beyond the nonlinear-Shannon Limit. We show nonlinear compensation of 7x114Gbit/s DP-QPSK channels, increasing system reach by 30%.
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nonlinear communication channels with capacity above the linear Shannon Limit
Optics Letters, 2012Co-Authors: Konstantin Turitsyn, Sergei K TuritsynAbstract:We prove that, under certain conditions, the capacity of an optical communication channel with in-line, nonlinear filtering (regeneration) elements can be higher than the Shannon capacity for the corresponding linear Gaussian white noise channel.