A locally recoverable code (LRC code) is a code over a finite alphabet such that every symbol in the encoding is a function of a small number of other symbols that form a recovering set. Bounds on the rate and distance of such codes have been extensively studied in the literature. In this paper we derive upper bounds on the rate and distance of codes in which every symbol has $t\geq 1$ disjoint recovering sets.
Locally recoverable codes are widely used in distributed and cloud storage systems. The objective of this paper is to present a construction of near MDS codes with oval polynomials and then determine the locality of the codes. It turns out that the near MDS codes and their duals are both distance-optimal and dimension-optimal locally recoverable codes. The lengths of the locally recoverable codes are different from known ones in the literature.
Locally Recoverable Codes with Availability $t\geq 2$ from Fiber Products of Curves
本文利用曲线的纤维积的结构，将Barg，Tamo和Vlaud Duffel给出的代数曲线上的局部可恢复码的构造推广到具有任意多个恢复集的代数曲线上.采用极大曲线，我们创建了几个新的家庭的本地可恢复的代码与多个恢复集，包括代码与两个恢复集的广义Giulietti和Kommarros（GK）曲线和铃木曲线，和新的本地可恢复的代码与许多恢复集的基础上的Hermitian曲线，使用一个纤维积建设的van der Geer和van der Vlugt。此外，我们考虑局部误差恢复和全局误差校正之间的关系，以及本地恢复任何固定数量的擦除模式所需的可用性。
A linear code with parameters $[n,k,n-k]$ is said to be almost maximum distance separable (AMDS for short). An AMDS code whose dual is also AMDS is referred to as an near maximum distance separable (NMDS for short) code. NMDS codes have nice applications in finite geometry, combinatorics, cryptography and data storage. In this paper, we first present several constructions of NMDS codes and determine their weight enumerators. In particular, some constructions produce NMDS codes with the same parameters but different weight enumerators. Then we determine the locality of the NMDS codes and obtain…
It was shown in \cite{GXY18} that the length $n$ of a $q$-ary linear locally recoverable code with distance $d\ge 5$ is upper bounded by $O(dq^3)$. Thus, it is a challenging problem to construct $q$-ary locally recoverable codes with distance $d\ge 5$ and length approaching the upper bound. The paper \cite{GXY18} also gave an algorithmic construction of $q$-ary locally recoverable codes with locality $r$ and length $n=Ω_r(q^2)$ for $d=5$ and $6$, where $Ω_r$ means that the implicit constant depends on locality $r$. In the present paper, we present an explicit construction of $q$-ary locally re…
The traditional definition of Integrated Interleaved (II) codes generally assumes that the component nested codes are either Reed-Solomon (RS) or shortened Reed-Solomon codes. By taking general classes of codes, we present a recursive construction of Extended Integrated Interleaved (EII) codes into multiple layers, a problem that brought attention in literature for II codes. The multiple layer approach allows for a hierarchical scheme where each layer of the code provides for a different locality. In particular, we present the erasure-correcting capability of the new codes and we show that the…
In this work we construct sequences of locally recoverable AG codes arising from a tower of function fields and give bound for the parameters of the obtained codes. In a particular case of a tower over $\mathbb{F}_{q^2}$ for any odd $q$, defined by Garcia and Stichtenoth in [GS2007], we show that the bound is sharp for the first code in the sequence, and we include a detailed analysis for the following codes in the sequence based on the distribution of rational places that split completely in the considered function field extension.
We construct families of locally recoverable codes with availability $t\geq 2$ using fiber products of curves, determine the exact minimum distance of many families, and prove a general theorem for minimum distance of such codes. The paper concludes with an exploration of parameters of codes from these families and the fiber product construction more generally. We show that fiber product codes can achieve arbitrarily large rate and arbitrarily small relative defect, and compare to known bounds and important constructions from the literature.
Hierarchical Locally Recoverable Codes on surfaces
IMPA（巴西数学纯应用与计算研究所）；Colorado College Department of Mathematics and Computer Science（科罗拉多学院数学与计算机科学系）；Department of Mathematics and Statistics, Oakland University（奥克兰大学数学与统计系）；Faculty of Science and Engineering - Bernoulli Institute, University of Groningen（格罗宁根大学理学院伯努利研究所）
In this paper we construct new optimal hierarchical locally recoverable codes. Our construction is based on a combination of the ideas of \cite{ballentine2019codes,sasidharan2015codes} with an algebraic number theoretical approach that allows to give a finer tuning of the minimum distance of the intermediate code (allowing larger dimension of the final code), and to remove restrictions on the arithmetic properties of $q$ compared with the size of the locality sets in the hierarchy. In turn, we manage to obtain codes with a wide set of parameters both for the size $q$ of the base field, and for…
Entanglement-Assisted Quantum Locally Recoverable Codes: Characterizations, Bounds, and Constructions
Nanyang Technological University（南洋理工大学）；VinUniversity（越南大学）；City University of Hong Kong（香港城市大学）；Nanjing University of Aeronautics and Astronautics（南京航空航天大学）；Hefei University of Technology（合肥工业大学）
A linear error correcting code is a subspace of a finite-dimensional space over a finite field with a fixed coordinate system. Such a code is said to be locally recoverable with locality $r$ if, for every coordinate, its value at a codeword can be deduced from the value of (certain) $r$ other coordinates of the codeword. These codes have found many recent applications, e.g., to distributed cloud storage. We will discuss the problem of constructing good locally recoverable codes and present some constructions using algebraic surfaces that improve previous constructions and sometimes provide cod…
Beyond Polynomials: Optimal Locally Recoverable Codes from Good Rational Functions
Southwest Jiaotong University（西南交通大学）；University of Paris VIII（巴黎第八大学）；CNRS, UMR 7539 LAGA, University of Paris XIII（法国国家科学研究中心，UMR 7539 LAGA，巴黎第十三大学）；China West Normal University（西华师范大学）
Local List Recovery of High-rate Tensor Codes and Applications
在这项工作中，我们给出了第一个高速率的本地列表可恢复代码的建设。列表恢复一直是编码理论中非常有用的构建块，我们的动机是使用这些代码作为这样的构建块。特别是，我们的建设给出了第一个容量实现本地列表可解码的代码（在恒定大小的字母表）;第一个容量实现全局列表可解码的代码与近线性时间列表解码算法（再一次，在恒定大小的字母表）;和Gilbert-Varshamov界上的二进制码的随机化结构，可以在近线性时间内唯一解码，具有比以前已知的更高的速率。我们的技术实际上非常简单，并且受到Gopalan，Guruswami和Raghavendra（Siam Journal on Computing，2011）用于列表解码张量代码的方法的启发。我们表明，张量的权力（全球）列表可恢复的代码是“近似”本地列表可恢复的，和“近似”的修改器可以通过预编码的消息与合适的本地可解码的代码被删除。用高速率全局列表可恢复代码和高速率局部可解码代码的已知构造来实例化该构造完成该构造。
Optimal pure quantum $(r,δ)$-locally recoverable codes from matrix-product construction
Universitat Jaume I（豪梅一世大学）；Institut Universitari de Matemàtiques i Aplicacions de Castelló（卡斯特利翁数学与应用大学研究所）；Universidad de Valladolid（巴利亚多利德大学）；IMUVA-Mathematics Research Institute（IMUVA数学研究所）
