论文标题
关于直接构图代码的性能
On the Performance of Direct Shaping Codes
论文作者
论文摘要
在这项工作中，我们研究了最近提出的直接构建代码，用于闪存。该速率1代码旨在通过在存储结构化数据时最大程度地减少程序单元格的平均分数来降低SLC的磨损（每单元格一位）。然后，我们描述了该算法的改编，该算法为MLC（每个单元格两个位）闪存提供了数据构图。它利用了一个依赖页面的成本模型，旨在与基于页面，基于页面的Wordline编程的标准过程兼容。我们还提供实验结果，证明将MLC数据塑造代码的性能应用于英语和中文文本。然后，我们研究在嘈杂的闪存设备中使用直接塑造代码的潜在误差传播属性。特别是，我们将误差传播建模为在多维空间中的偏见随机行走。我们证明了误差传播概率上的上限，并提出了一种算法，该算法可以在数值上接近下限。最后，我们研究了直接塑造代码的渐近性能。我们证明，SLC直接塑造代码是次优的，因为它只能在源分布的某些条件下达到1 rate-1代码的最低平均成本。
In this work, we study a recently proposed direct shaping code for flash memory. This rate-1 code is designed to reduce the wear for SLC (one bit per cell) flash by minimizing the average fraction of programmed cells when storing structured data. Then we describe an adaptation of this algorithm that provides data shaping for MLC (two bits per cell) flash memory. It makes use of a page-dependent cost model and is designed to be compatible with the standard procedure of row-by-row, page-based, wordline programming. We also give experimental results demonstrating the performance of MLC data shaping codes when applied to English and Chinese language text. We then study the potential error propagation properties of direct shaping codes when used in a noisy flash device. In particular, we model the error propagation as a biased random walk in a multidimensional space. We prove an upper bound on the error propagation probability and propose an algorithm that can numerically approach a lower bound. Finally, we study the asymptotic performance of direct shaping codes. We prove that the SLC direct shaping code is suboptimal in the sense that it can only achieve the minimum average cost for a rate-1 code under certain conditions on the source distribution.
