论文标题
管理设备生命周期：M/T/Q/P-LC闪存记忆的可重构约束代码
Managing Device Lifecycle: Reconfigurable Constrained Codes for M/T/Q/P-LC Flash Memories
论文作者
论文摘要
闪存设备正在赢得与磁性记录设备相对于存储密度的竞争。该结果是由于物理学的进步而导致的，该物理的进步允许每个单元格存储一个以上的位置，再加上信号处理的进步，从而降低了物理不稳定性的效果。受限的代码用于存储中，以避免有问题的模式。最近，我们引入了用于数据存储和数据传输的二进制对称词典有序的约束代码（LECO代码）。本文介绍了支持非二进制物理基材的简单约束代码。多，三重，四，Quad和当前开发的PENTA级单元格（M/T/Q/P-LC）闪存记忆。如果有问题的模式随时间变化，则可以轻松修改新代码。这些代码旨在减轻细胞间干扰，这是闪存设备中错误的关键来源。误差的发生是浮栅晶体管内外寄生电容的结果，导致电荷传播从编程到最高电荷水平到被编程到较低水平的相邻单元。新代码称为$ q $ - 元素非对称机业码（QA-LOCO代码），而构造元素代码先前为单级单元格（SLC）闪存设备（A-Loco代码）设计。 QA-Loco代码适用于每个单元格的任何数字，$ q $的闪光设备。对于$ Q \ geq 4 $，我们表明QA-Loco代码可以达到大于$ 0.95 \ log_2 q $信息位每个编码符号的费率。编码和解码的复杂性是适度的，重新配置代码就像重新编程加法器一样容易。能力实现的速度，负担得起的编码复杂性以及可重新配置的易用性支持M/T/Q/Q/P-LC闪存闪存设备的不断增长，以及随着这些设备的特性随时间而变化的生命周期管理。
Flash memory devices are winning the competition for storage density against magnetic recording devices. This outcome results from advances in physics that allow storage of more than one bit per cell, coupled with advances in signal processing that reduce the effect of physical instabilities. Constrained codes are used in storage to avoid problematic patterns. Recently, we introduced binary symmetric lexicographically-ordered constrained codes (LOCO codes) for data storage and data transmission. This paper introduces simple constrained codes that support non-binary physical substrates; multi, triple, quad, and the currently-in-development penta-level cell (M/T/Q/P-LC) Flash memories. The new codes can be easily modified if problematic patterns change with time. These codes are designed to mitigate inter-cell interference, which is a critical source of error in Flash devices. The occurrence of errors is a consequence of parasitic capacitances in and across floating gate transistors, resulting in charge propagation from cells being programmed to the highest charge level to neighboring cells being programmed to lower levels. The new codes are called $q$-ary asymmetric LOCO codes (QA-LOCO codes), and the construction subsumes codes previously designed for single-level cell (SLC) Flash devices (A-LOCO codes). QA-LOCO codes work for a Flash device with any number, $q$, of levels per cell. For $q \geq 4$, we show that QA-LOCO codes can achieve rates greater than $0.95 \log_2 q$ information bits per coded symbol. The complexity of encoding and decoding is modest, and reconfiguring a code is as easy as reprogramming an adder. Capacity-achieving rates, affordable encoding-decoding complexity, and ease of reconfigurability support the growing development of M/T/Q/P-LC Flash memory devices, as well as lifecycle management as the characteristics of these devices change with time.
