Read Voltage Optimization in MLC NAND Flash Memory via the Density Evolution
Read Voltage Optimization in MLC NAND Flash Memory via the Density Evolution
复制标题
通过密度演化优化 MLC NAND 闪存的读取电压
DOI：
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发表时间：
2019
期刊：
影响因子：
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通讯作者：
P. Supnithi
中科院分区：
文献类型：
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作者：
Chatuporn Duangthong;W. Phakphisut;P. Supnithi
多级单元（MLC）NAND闪存通常可以使用多次读取来获得用于LDPC解码器的软信息。多次读取给出量化到一定水平的软信息。主要的挑战是必须精确地选择读取电压以提供更好的软信息。在先前的工作中，选择读取电压，使得软信息具有最大互信息（MMI）。然而，LDPC译码器的纠错能力没有被考虑。因此，在这项工作中，我们分析了LDPC解码器的性能密度演化，从而量化的软信息。然后，对于给定的LDPC码的最佳读取电压。因此，对于具有通过密度演化优化的读取电压的规则LDPC码，与MMI技术相比可以提供更低的BER性能。
The multi-level-cell (MLC) NAND flash memory can typically use multiple reads for obtaining soft information for the LDPC decoder. The multiple reads give the soft information which is quantized to a certain level. The major challenge is that the read voltages must be precisely selected to provide better soft information. In the previous work, the read voltages are selected so that the soft information has the maximum mutual information (MMI). However, the error-correction capability of LDPC decoder is not considered. Therefore, in this work, we analyze the performance of LDPC decoder by density evolution whereby the soft information is quantized. Then the optimal read voltages for given LDPC codes are obtained. As a result, for a regular LDPC code with the read voltages optimized by density evolution can provide the lower BER performance compared with the MMI technique.