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arXiv 0901.1866cs.ITmath.IT
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利用随机压缩器实现码的容量

Capacity Achieving Codes From Randomness Condensers

Mahdi Cheraghchi

摘要:

我们建立了一个一般框架,建设小合奏的能力实现线性代码的广泛(不一定是无记忆的)离散对称信道,特别是二进制擦除和对称信道。在我们的构造中使用的主要工具是随机性提取器和无损压缩器的概念,它们被认为是理论计算机科学中的核心工具。与随机码一样,所得到的系综在基的任何变化下都保持其容量实现特性。利用已知的显式构造的凝聚器,我们得到特定的合奏,其大小是小的多项式的块长度。通过将我们的构造应用于Justesen的级联方案(Justesen,1972),我们获得了BEC的显式容量实现码(分别为,BSC)具有几乎线性时间编码和几乎线性时间(分别,二次时间)解码和指数小错误概率。

英文摘要:

We establish a general framework for construction of small ensembles of capacity achieving linear codes for a wide range of (not necessarily memoryless) discrete symmetric channels, and in particular, the binary erasure and symmetric channels. The main tool used in our constructions is the notion of randomness extractors and lossless condensers that are regarded as central tools in theoretical computer science. Same as random codes, the resulting ensembles preserve their capacity achieving properties under any change of basis. Using known explicit constructions of condensers, we obtain specific ensembles whose size is as small as polynomial in the block length. By applying our construction to Justesen's concatenation scheme (Justesen, 1972) we obtain explicit capacity achieving codes for BEC (resp., BSC) with almost linear time encoding and almost linear time (resp., quadratic time) decoding and exponentially small error probability.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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