Channel Coding for Nonvolatile Memory Technologies: Theoretical Advances and Practical Considerations
Channel Coding for Nonvolatile Memory Technologies: Theoretical Advances and Practical Considerations
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DOI：
10.1109/jproc.2017.2694613
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发表时间：
2017-05
影响因子：
20.6
通讯作者：
L. Dolecek;Yuval Cassuto
中科院分区：
文献类型：
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作者：
L. Dolecek;Yuval Cassuto
存储或内存设备中的每一点信息都受多种性能规格的约束，并且会受到各种可靠性障碍。在另一端，驯服的物理过程记住我们的位为其可靠性提供了不断的风险来源。这些包括各种噪声源，访问限制，间间干扰，细胞变异性以及更多问题。将这个绩效数字的向量与可靠性问题的向量联系在一起是新兴编码工具和技术的丰富矩阵。渠道编码方案可确保目标的可靠性和性能，并且自新生年龄以来一直处于内存系统的核心。在这项调查中，我们首先概述了通道编码的基本原理，并总结了已在非易失性记忆（NVMS）中使用的众所周知的代码。接下来，我们证明了为什么传统的编码基于对称渠道模型普遍存在接近，并且对锤式指标的优化无法满足现代记忆的需求。然后，我们讨论最近提出的一些创新编码方案。每个编码方案的背后都是一个有趣的理论框架，基于数学和信息科学的深刻思想。我们还调查了深层理论和存储性能之间最迷人的桥梁。虽然该调查的重点主要放在普遍的多级NAND FLASH上，但我们设想其他受益的内存技术将包括相变内存，电阻性记忆等。
Every bit of information in a storage or memory device is bound by a multitude of performance specifications, and is subject to a variety of reliability impediments. At the other end, the physical processes tamed to remember our bits offer a constant source of risk to their reliability. These include a variety of noise sources, access restrictions, intercell interferences, cell variabilities, and many more issues. Tying together this vector of performance figures with that vector of reliability issues is a rich matrix of emerging coding tools and techniques. Channel coding schemes ensure target reliability and performance and have been at the core of memory systems since their nascent age. In this survey, we first overview the fundamentals of channel coding and summarize well-known codes that have been used in nonvolatile memories (NVMs). Next, we demonstrate why the conventional coding approaches ubiquitously based on symmetric channel models and optimization for the Hamming metric fail to address the needs of modern memories. We then discuss several recently proposed innovative coding schemes. Behind each coding scheme lies an interesting theoretical framework, building on deep ideas from mathematics and the information sciences. We also survey some of the most fascinating bridges between deep theory and storage performance. While the focus of this survey is primarily on the pervasive multilevel NAND Flash, we envision that other benefiting memory technologies will include phase change memory, resistive memories, and others.