共查询到19条相似文献,搜索用时 46 毫秒
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LDPC码是迄今为止试验中最接近Shamon极限的信道编码,也为短波通信指出了发展方向。本文分析了在短波信道下LDPC码的性能随码长、迭代次数、编码速率的变化,展示了其优良的性能。 相似文献
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基于协同优化算法推导出一种Reed-Solomon(RS)码的迭代软判决译码(SDD)算法。该算法属于消息传递算法,具有严格的理论基础。仿真结果表明,该算法相对于硬判决译码(HDD)能够获得有效的软判决译码增益,对于(15,9)RS码在误帧率(FER)为4×10-4时有0.3~1.3dB的增益;同时译码复杂度低,具有很好的工程实用性。此外该算法是一类软输入软输出(SISO)译码算法,能够应用于以RS码为子码的复合码,如级连码和乘积码的迭代译码。 相似文献
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《中国计量学院学报》2017,(1):76-80
针对目前缺少对LDPC码TDMP算法理论分析的问题,提出了TDMP算法的高斯近似.基于BP算法和对称条件,得到结果收敛的TDMP算法的高斯近似.利用高斯近似来分析TDMP算法的译码收敛性,为论证TDMP算法的优越性能提供了理论依据.基于Wimax标准,分别对BP算法和TDMP算法的高斯近似进行仿真.仿真结果表明,在相同情况下,TDMP算法译码收敛速度更快,需要的迭代次数更少.同时,给出了TDMP算法分别采用高斯近似和密度进化时的门限值,它们的差别仅为0.03~0.08dB. 相似文献
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本文首先介绍了删除信道,及删除信道下LDPC码的优势,重点讨论了几种优化设计LDPC图的算法。其次,提出了一种限制环长加边算法,该算法比以往的优化算法有更小的复杂度和更好的性能。最后,对算法进行了仿真。 相似文献
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为了提高图像重建质量,提出量子比特平面编码算法。首先进行图像像素灰度段编码,获得中间段灰度级滤波矩阵;然后量子比特经过Walsh-Hadamard变换,将输入图像像素分解出低频部分和高频部分;接着分别对正系数矩阵和负系数矩阵扫描,在正负系数比特平面码流之间插入一个比特标志;最后给出了图像重建过程。实验仿真显示本文算法的重建效果清晰,指标分析图像信噪比最大,均方根误差较接近于0。 相似文献
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Tomik Yaghoobian Ian F. Blake 《Applicable Algebra in Engineering, Communication and Computing》1994,5(1):23-43
The subject of decoding Reed-Solomon codes is considered. By reformulating the Berlekamp and Welch key equation and introducing new versions of this key equation, two new decoding algorithms for Reed-Solomon codes will be presented. The two new decoding algorithms are significant for three reasons. Firstly the new equations and algorithms represent a novel approach to the extensively researched problem of decoding Reed-Solomon codes. Secondly the algorithms have algorithmic and implementation complexity comparable to existing decoding algorithms, and as such present a viable solution for decoding Reed-Solomon codes. Thirdly the new ideas presented suggest a direction for future research. The first algorithm uses the extended Euclidean algorithm and is very efficient for a systolic VLSI implementation. The second decoding algorithm presented is similar in nature to the original decoding algorithm of Peterson except that the syndromes do not need to be computed and the remainders are used directly. It has a regular structure and will be efficient for implementation only for correcting a small number of errors. A systolic design for computing the Lagrange interpolation of a polynomial, which is needed for the first decoding algorithm, is also presented.This research was supported by a grant from the Canadian Institute for Telecommunications Research under the NCE program of the Government of Canada 相似文献
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Alexey E. Ashikhmin Simon N. Litsyn 《Applicable Algebra in Engineering, Communication and Computing》1996,7(4):299-308
A minimum distance decoding algorithm for non-binary first order Reed-Muller codes is described. Suggested decoding is based on a generalization of the fast Hadamard transform to the non-binary case. We also propose a fast decoding algorithm for non-binary first order Reed-Muller codes with complexity proportional to the length of the code. This algorithm provides decoding within the limits guaranteed by the minimum distance of the code.Partly supported by the Guastallo Fellowship. This work was presented in part at the 9th International Symposium Applied Algebra, Algebraic Algorithms and Error-Correcting Codes, New Orleans, USA, October 1991 相似文献
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针对低密度奇偶校验码(LDPC)中环的存在影响LDPC码性能的问题,研究了基于校验阵的有限长LDPC码的去环和优化,指出搜索随机矩阵的方法比较直观,但计算量是码长和列重乘积的指数函数.给出了搜索并替换的去环方法,该方法能够显著减小短环对译码性能的影响.计算机仿真结果表明,去除长度为4和6的环能够在误比特率为10-5时获得0 5dB的编码增益.讨论了去环图的优化和判定准则,计算机仿真结果表明,优选的去环编码方案的性能要好于未经优选的方案. 相似文献
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Henry O’Keeffe Patrick Fitzpatrick 《Applicable Algebra in Engineering, Communication and Computing》2007,18(5):445-466
We show how our Gröbner basis algorithm, which was previously applied to list decoding of Reed Solomon codes, can be used in the hard and soft decision list decoding of Algebraic Geometry codes. In addition, we present a linear functional version of our Gröbner basis algorithm in order to facilitate comparisons with methods based on duality. 相似文献
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On one hand, PSA results are increasingly used in decision making, system management and optimization of system design. On the other hand, when severe accidental transients are considered, dynamic reliability appears appropriate to account for the complex interaction between the transitions between hardware configurations, the operator behavior and the dynamic evolution of the system. This paper presents an exploratory work in which the estimation of the system unreliability in a dynamic context is coupled with an optimization algorithm to determine the “best” safety policy. Because some reliability parameters are likely to be distributed, the cost function to be minimized turns out to be a random variable. Stochastic programming techniques are therefore envisioned to determine an optimal strategy. Monte Carlo simulation is used at all stages of the computations, from the estimation of the system unreliability to that of the stochastic quasi-gradient. The optimization algorithm is illustrated on a HNO3 supply system. 相似文献
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In many situations, we want to accept or reject a population with small or finite population size. In this paper, we will describe Bayesian and non‐Bayesian approaches for the reliability demonstration test based on the samples from a finite population. The Bayesian method is an approach that combines prior experience with newer test data in the application of statistical tools for reliability quantification. When test time and/or sample quantity is limited, the Bayesian approach should be considered. In this paper, a non‐Bayesian reliability demonstration test is considered for both finite and large population cases. The Bayesian approach with ‘uniform’ prior distributions, Polya prior distributions, and sequential sampling is also presented. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献