共查询到19条相似文献,搜索用时 672 毫秒
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线性拟等重码的结构分析 总被引:3,自引:0,他引:3
C为二元正侧线性拟等重码,我们证明:(1)如果n=2d则C等价于1阶;(2)如何为素数,则C等价于RM(k-1)删除第1个分量后得到的线性码,另外,利用编码理论中著名的Mac William恒等式给出文(1)定量1的一个新的简洁证明。 相似文献
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两类新的线性分组码的译码 总被引:1,自引:0,他引:1
本文推广了Pless由四元线性分组码构造Golay码和由三元(4,2,3)线性分组码构造三元(12,6,6)Golay码的投影方法,给出了由四元(n,k,d)线性分组码构造的二元(4n,n+2k,≥min(8,n,2d)线性分组码和由三元(n,k,d)线性分组码构造的三元(3n,n+k,≥min(n,2d,6)线性分组码,并根据所得码的结构给出了有效的最大似然译码算法。 相似文献
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定义了一类新的线性码,它具有结构简单、码率较大的特点。利用一般方法产生了纠多个错的线性码。计算出这类线性码的重量分布,关于码的自同构群也得到了一些结果。 相似文献
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本文给出了检错好码的定义,证明了GF(2)上的(n,k)线性分组码为检错好码的充要条件是其对偶码也为检错好码。文中还得到了关于检错好码的一系列新的结果。对二元(n,k)线性分组码,我们给出了不可检错误概率新的下限。这些限只与n和k有关,而与码的重量结构无关。 相似文献
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广义Hamming重量和等重码 总被引:8,自引:0,他引:8
本文将线性码的广义Hamming重量的概念推广到线性码上去,并导出了一种广义Elias界,对于线性等重码,本文给出了其完整的重量谱系。 相似文献
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环F2+uF2上线性码及其对偶码的二元象 总被引:1,自引:0,他引:1
利用环F2+uF2上线性码C的生成矩阵给出了码C的对偶码C^┴及其Gray象Ф(C)的生成矩阵,证明了环F2+uF2上线性码及其对偶码的Gray象仍是对偶码。并由此给出了一个环F2+uF2如上线性码为自对偶码的充要条件。 相似文献
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交织长度的识别是交织器识别过程中重要的步骤,关系到纠错码识别和信息的获取,具有重要的研究价值。文中简要介绍矩阵分析法,针对矩阵分析法容错能力不强的缺点,借助码重分布的概念,提出利用块重分布识别低码率二进制线性分组码序列交织长度的方法。最后,对两种方法进行仿真对比,分析了各自的适用范围和容错能力。 相似文献
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Hongxia Jin Mario Blaum 《IEEE transactions on information theory / Professional Technical Group on Information Theory》2007,53(2):804-808
In this correspondence, the combinatorial properties of traceability codes constructed from error-correcting codes are studied. Necessary and sufficient conditions for traceability codes constructed from maximum-distance separable (MDS) codes are provided. The known sufficient conditions for a traceability code are proven to be also necessary for linear MDS codes 相似文献
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《Communications, IEEE Transactions on》2006,54(5):955-955
In broadcast scenarios or in the absence of accurate channel probability distribution information, code design for consistent channel-by-channel performance, rather than average performance over a channel distribution, may be desirable. Root and Varaiya's compound channel theorem for linear Gaussian channels promises the existence of universal codes that operate reliably whenever the channel mutual information (MI) is above the transmitted rate. This paper presents 2-D trellis codes that provide such universal performance over the compound linear vector Gaussian channel when demultiplexed over two, three, and four transmit antennas. The presented trellis codes are found by an exhaustive search that guarantees consistent performance on every matrix channel that supports the information transmission rate with an MI gap that is similar to the capacity gap of a well-designed additive white Gaussian noise (AWGN)-specific code on the AWGN channel. As a result of their channel-by-channel consistency, the universal trellis codes presented here also deliver comparable, or in some cases, superior frame-error rate and bit-error rate performance under quasi-static Rayleigh fading to trellis codes of similar complexity that are designed specifically for the quasi-static Rayleigh fading scenario. 相似文献
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Jin Lu Jos M. F. Moura 《IEEE transactions on information theory / Professional Technical Group on Information Theory》2007,53(3):1080-1094
We consider turbo-structured low-density parity-check (TS-LDPC) codes-structured regular codes whose Tanner graph is composed of two trees connected by an interleaver. TS-LDPC codes with good girth properties are easy to construct: careful design of the interleaver component prevents short cycles of any desired length in its Tanner graph. We present algorithms to construct TS-LDPC codes with arbitrary column weight jges2 and row weight k and arbitrary girth g. We develop a linear complexity encoding algorithm for a type of TS-LDPC codes-encoding friendly TS-LDPC (EFTS-LDPC) codes. Simulation results demonstrate that the bit-error rate (BER) performance at low signal-to-noise ratio (SNR) is competitive with the error performance of random LDPC codes of the same size, with better error floor properties at high SNR 相似文献
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近年来,结构化低密度奇偶校验(LDPC)码的构造方法受到了广泛地关注.本文提出了一种利用最大距离分割(MDS)编码构造结构化LDPC码的思路.该思路将基于两个信息符号的RS码构造LDPC码的方法扩展至适用于所有的MDS码.本文以具有MDS特性的卷积码为例详细描述该构造方法的细节,并构造了码长从255比特到4095比特的高码率LDPC码.由于卷积码的MDS定义不同于线性分组码,因此本文给出了一种对卷积码截短的方法及其必要的证明.仿真结果表明,本文构造MDS-Conv-LDPC码的性能优于随机构造的LDPC码. 相似文献
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《IEEE transactions on information theory / Professional Technical Group on Information Theory》2007,53(6):2267-2270
From a linear block code B over the Galois ring GR(4, m) with a k times n generator matrix and minimum Hamming distance d, a rate-k/n convolutional code over the ring Z4 with squared Euclidean free distance at least 2d and a nonrecursive encoder with memory at most m - 1 is constructed. When the generator matrix of B is systematic, the convolutional encoder is systematic, basic, noncatastrophic and minimal. Long codes constructed in this manner are shown to satisfy a Gilbert-Varshnmov bound. 相似文献