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arXiv 1301.6599cs.ITmath.IT
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非二进制删除信道容量的上界

An Upper Bound on the Capacity of non-Binary Deletion Channels

Mojtaba Rahmati, Tolga M. Duman

摘要:

我们推导出非二进制删除通道的容量上界。虽然二进制删除通道多年来受到了极大的关注,并且已经推导出其容量的许多上限和下限,但对于非二进制情况的此类研究在很大程度上缺失。现有技术如下:作为普通的上限,可以使用具有与删除信道相同的输入字母表的擦除信道的容量,并且作为下限,Diggavi和Grossglauser的结果是可用的。在本文中,我们推导出第一个非平凡的非二进制删除信道容量上界,并减少与现有的可达速率的差距。为了得到结果,我们首先证明了具有删除概率$d$的2K元删除信道的容量(用$C_{2K}(d)$表示)与具有相同删除概率$C_2(d)$的二进制删除信道的容量(即,$C_{2K}(d)\leq C_2(d)+(1-d)\log(K)$)之间的不等式。然后利用已有的二进制删除信道容量的上界,得到了2K进制删除信道容量的上界。我们通过例子来说明使用新的界限,并讨论其渐近行为$d \rightarrow 0$。

英文摘要:

We derive an upper bound on the capacity of non-binary deletion channels. Although binary deletion channels have received significant attention over the years, and many upper and lower bounds on their capacity have been derived, such studies for the non-binary case are largely missing. The state of the art is the following: as a trivial upper bound, capacity of an erasure channel with the same input alphabet as the deletion channel can be used, and as a lower bound the results by Diggavi and Grossglauser are available. In this paper, we derive the first non-trivial non-binary deletion channel capacity upper bound and reduce the gap with the existing achievable rates. To derive the results we first prove an inequality between the capacity of a 2K-ary deletion channel with deletion probability $d$, denoted by $C_{2K}(d)$, and the capacity of the binary deletion channel with the same deletion probability, $C_2(d)$, that is, $C_{2K}(d)\leq C_2(d)+(1-d)\log(K)$. Then by employing some existing upper bounds on the capacity of the binary deletion channel, we obtain upper bounds on the capacity of the 2K-ary deletion channel. We illustrate via examples the use of the new bounds and discuss their asymptotic behavior as $d \rightarrow 0$.

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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