When Do Low-Rate Concatenated Codes Approach The Gilbert-Varshamov Bound?

Fuente: arXiv
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Main Authors: Doron, Dean, Mosheiff, Jonathan, Wootters, Mary
Format: Preprint
Published: 2024
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author Doron, Dean
Mosheiff, Jonathan
Wootters, Mary
author_facet Doron, Dean
Mosheiff, Jonathan
Wootters, Mary
contents The Gilbert--Varshamov (GV) bound is a classical existential result in coding theory. It implies that a random linear binary code of rate $ε^2$ has relative distance at least $\frac{1}{2} - O(ε)$ with high probability. However, it is a major challenge to construct explicit codes with similar parameters. One hope to derandomize the Gilbert--Varshamov construction is with code concatenation: We begin with a (hopefully explicit) outer code ${C}_\mathrm{out}$ over a large alphabet, and concatenate that with a small binary random linear code ${C}_\mathrm{in}$. It is known that when we use independent small codes for each coordinate, then the result lies on the GV bound with high probability, but this still uses a lot of randomness. In this paper, we consider the question of whether code concatenation with a single random linear inner code ${C}_\mathrm{in}$ can lie on the GV bound; and if so what conditions on ${C}_\mathrm{out}$ are sufficient for this. We show that first, there do exist linear outer codes ${C}_\mathrm{out}$ that are "good" for concatenation in this sense (in fact, most linear codes codes are good). We also provide two sufficient conditions for ${C}_\mathrm{out}$, so that if ${C}_\mathrm{out}$ satisfies these, ${C}_\mathrm{out}\circ {C}_\mathrm{in}$ will likely lie on the GV bound. We hope that these conditions may inspire future work towards constructing explicit codes ${C}_\mathrm{out}$.
format Preprint
id arxiv_https___arxiv_org_abs_2405_08584
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle When Do Low-Rate Concatenated Codes Approach The Gilbert-Varshamov Bound?
Doron, Dean
Mosheiff, Jonathan
Wootters, Mary
Information Theory
Computational Complexity
The Gilbert--Varshamov (GV) bound is a classical existential result in coding theory. It implies that a random linear binary code of rate $ε^2$ has relative distance at least $\frac{1}{2} - O(ε)$ with high probability. However, it is a major challenge to construct explicit codes with similar parameters. One hope to derandomize the Gilbert--Varshamov construction is with code concatenation: We begin with a (hopefully explicit) outer code ${C}_\mathrm{out}$ over a large alphabet, and concatenate that with a small binary random linear code ${C}_\mathrm{in}$. It is known that when we use independent small codes for each coordinate, then the result lies on the GV bound with high probability, but this still uses a lot of randomness. In this paper, we consider the question of whether code concatenation with a single random linear inner code ${C}_\mathrm{in}$ can lie on the GV bound; and if so what conditions on ${C}_\mathrm{out}$ are sufficient for this. We show that first, there do exist linear outer codes ${C}_\mathrm{out}$ that are "good" for concatenation in this sense (in fact, most linear codes codes are good). We also provide two sufficient conditions for ${C}_\mathrm{out}$, so that if ${C}_\mathrm{out}$ satisfies these, ${C}_\mathrm{out}\circ {C}_\mathrm{in}$ will likely lie on the GV bound. We hope that these conditions may inspire future work towards constructing explicit codes ${C}_\mathrm{out}$.
title When Do Low-Rate Concatenated Codes Approach The Gilbert-Varshamov Bound?
topic Information Theory
Computational Complexity
url https://arxiv.org/abs/2405.08584