arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2008.07236cs.ITmath.COmath.IT
收藏

关于在BSC上对常数错误率译码的码

On codes decoding a constant fraction of errors on the BSC

Alex Samorodnitsky, Ori Sberlo

摘要:

利用Kudekar等人的技术和结果,我们加强了第一作者所证明的在BEC上实现容量的线性码的重量分布的界限。特别是,我们证明了,对于任何双传递二进制线性码$C \subseteq \{0,1\}^n$率$0 < R < 1$与重量分布$\left(a_0,...,a_n\right)$持有$a_i \le 2^{o(n)} \cdot (1-R)^{-2 \ln 2 \cdot \min\{i, n-i\}}$。对于最小距离至少为$Ω\left(n^c\right)$,$0 < c \le 1$的双传递码,在这个界中$2^{o(n)}$的误差因子可以被去除,代价是用更小的常数$a = a(R,c) < 1- R$代替$1-R$.此外,在Reed-Muller码的特殊情况下,由于这些码的额外对称性,可以基本上没有成本地去除该误差因素。这意味着,对于速率为$R$且最小距离至少为$Ω\left(n^c\right)$的任何双传递码$C$,存在正常数$p = p(R,c)$,使得$C$在$p < p(R,c)$的情况下以高概率解码$\mathrm{BSC}(p)$上的错误。对于速率足够低(小于某个绝对常数)的双传递码,可以忽略对最小距离的要求,因此这个临界概率$p(R)$仅取决于$R$。此外,$p(R) \rightarrow \frac12$作为$R \rightarrow 0$。特别地,如果\[ R ~<~ 1 - \big(4p(1-p)\big)^{\frac{1}{4 \ln 2}}, \]回答阿贝、哈兹拉和纳丘姆的问题,则速率为$R$的里德-穆勒码$C$以高概率解码$\mathrm{BSC}(p)$上的错误。

英文摘要:

Using techniques and results from Kudekar et al. we strengthen the bounds on the weight distribution of linear codes achieving capacity on the BEC, which were shown by the first author. In particular, we show that for any doubly transitive binary linear code $C \subseteq \{0,1\}^n$ of rate $0 < R < 1$ with weight distribution $\left(a_0,...,a_n\right)$ holds $a_i \le 2^{o(n)} \cdot (1-R)^{-2 \ln 2 \cdot \min\{i, n-i\}}$. For doubly transitive codes with minimal distance at least $Ω\left(n^c\right)$, $0 < c \le 1$, the error factor of $2^{o(n)}$ in this bound can be removed at the cost of replacing $1-R$ with a smaller constant $a = a(R,c) < 1- R$. Moreover, in the special case of Reed-Muller codes, due to the additional symmetries of these codes, this error factor can be removed at essentially no cost. This implies that for any doubly transitive code $C$ of rate $R$ with minimal distance at least $Ω\left(n^c\right)$, there exists a positive constant $p = p(R,c)$ such that $C$ decodes errors on $\mathrm{BSC}(p)$ with high probability if $p < p(R,c)$. For doubly transitive codes of a sufficiently low rate (smaller than some absolute constant) the requirement on the minimal distance can be omitted, and hence this critical probability $p(R)$ depends only on $R$. Furthermore, $p(R) \rightarrow \frac12$ as $R \rightarrow 0$. In particular, a Reed-Muller code $C$ of rate $R$ decodes errors on $\mathrm{BSC}(p)$ with high probability if \[ R ~<~ 1 - \big(4p(1-p)\big)^{\frac{1}{4 \ln 2}}, \] answering a question of Abbe, Hazla, and Nachum.

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。

↑