LDPC Coding Scheme for Improving the Reliability of Multi-Level-Cell NAND Flash Memory in Radiation Environments  

作　　者：Guangjun Ge Liuguo Yin 

机构地区：[1]School of Aerospace,Tsinghua University,Beijing 100084,China [2]EDA Laboratory,Research Institute of Tsinghua University in Shenzhen,Shenzhen 518057,China

出　　处：《China Communications》2017年第8期10-21,共12页中国通信（英文版）

基　　金：supported by the National Basic Research Project of China(973)(2013CB329006);National Natural Science Foundation of China(NSFC,91538203);the new strategic industries development projects of Shenzhen City(JCYJ20150403155812833)

摘　　要：Utilizing commercial off-the-shelf(COTS) components in satellites has received much attention due to the low cost. However, commercial memories suffer severe reliability problems in radiation environments. This paper studies the low-density parity-check(LDPC) coding scheme for improving the reliability of multi-level-cell(MLC) NAND Flash memory in radiation environments. Firstly, based on existing physical experiment works, we introduce a new error model for heavyion irradiations; secondly, we explore the optimization of writing voltage allocation to maximize the capacity of the storage channel; thirdly, we design the degree distribution of LDPC codes that is specially suitable for the proposed model; finally, we propose a joint detection-decoding scheme based on LDPC codes, which estimates the storage channel state and executes an adaptive log-likelihood ratio(LLR) calculation to achieve better performance. Simulation results show that, compared with the conventional LDPC coding scheme, the proposed scheme may almost double the lifetime of the MLC NAND Flash memory in radiation environments.Utilizing commercial off-the-shelf（COTS） components in satellites has received much attention due to the low cost. However, commercial memories suffer severe reliability problems in radiation environments. This paper studies the low-density parity-check（LDPC） coding scheme for improving the reliability of multi-level-cell（MLC） NAND Flash memory in radiation environments. Firstly, based on existing physical experiment works, we introduce a new error model for heavyion irradiations; secondly, we explore the optimization of writing voltage allocation to maximize the capacity of the storage channel; thirdly, we design the degree distribution of LDPC codes that is specially suitable for the proposed model; finally, we propose a joint detection-decoding scheme based on LDPC codes, which estimates the storage channel state and executes an adaptive log-likelihood ratio（LLR） calculation to achieve better performance. Simulation results show that, compared with the conventional LDPC coding scheme, the proposed scheme may almost double the lifetime of the MLC NAND Flash memory in radiation environments.

关 键 词：low-density parity-check（LDPC） coding multi-level-cell（MLC） NAND Flash memory joint detection-decoding commercial off-the-shelf（COTS） components space radiation environments 

分 类 号：TN911.22[电子电信—通信与信息系统] TP333[电子电信—信息与通信工程]