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关于码的停止距离和停止冗余度

On the Stopping Distance and the Stopping Redundancy of Codes

Moshe Schwartz, Alexander Vardy

摘要:

现在众所周知,线性码$C$在二进制擦除信道(和其它信道)上的迭代解码下的性能由$C$的Tanner图中的最小停止集的大小确定。最近的几篇论文将该参数称为$C$的\emph{stopping distance} $s$。这有点用词不当,因为$C$的Tanner图中的最小停止集的大小取决于奇偶校验矩阵的相应选择。很容易看出,$s \le d$,其中$d$是$C$的最小汉明距离,我们表明,它总是可以选择一个奇偶校验矩阵$C$(有足够多的依赖行),使$s = d$。因此,我们引入一个新的参数,称为$C$的\emph{stopping redundancy},定义为$C$的奇偶校验矩阵$H$中的最小行数,使得相应的停止距离$s(H)$达到其最大可能值,即$s(H) = d$。然后,我们推导出一般的线性码的停止冗余的界限。我们还研究了几种简单的方法来构造代码从其他代码,并研究这些结构的停止冗余的效果。具体来说,对于家庭的二进制里德-穆勒码(所有订单),我们证明了他们的停止冗余是最多的一个常数倍,他们的常规冗余。我们证明了二进制和三进制扩展Golay码的停止冗余分别至多为35和22。最后给出了MDS码停止冗余度的上下界。

英文摘要:

It is now well known that the performance of a linear code $C$ under iterative decoding on a binary erasure channel (and other channels) is determined by the size of the smallest stopping set in the Tanner graph for $C$. Several recent papers refer to this parameter as the \emph{stopping distance} $s$ of $C$. This is somewhat of a misnomer since the size of the smallest stopping set in the Tanner graph for $C$ depends on the corresponding choice of a parity-check matrix. It is easy to see that $s \le d$, where $d$ is the minimum Hamming distance of $C$, and we show that it is always possible to choose a parity-check matrix for $C$ (with sufficiently many dependent rows) such that $s = d$. We thus introduce a new parameter, termed the \emph{stopping redundancy} of $C$, defined as the minimum number of rows in a parity-check matrix $H$ for $C$ such that the corresponding stopping distance $s(H)$ attains its largest possible value, namely $s(H) = d$. We then derive general bounds on the stopping redundancy of linear codes. We also examine several simple ways of constructing codes from other codes, and study the effect of these constructions on the stopping redundancy. Specifically, for the family of binary Reed-Muller codes (of all orders), we prove that their stopping redundancy is at most a constant times their conventional redundancy. We show that the stopping redundancies of the binary and ternary extended Golay codes are at most 35 and 22, respectively. Finally, we provide upper and lower bounds on the stopping redundancy of MDS codes.

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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