Multilevel NAND Flash Memories with Superposition Modulation:A Non-Orthogonal Multi-User Communication Perspective  

作　　者：Zhou Xuan Ma Zheng Zhou Yi Tang Xiaohu Fan Pingzhi 

机构地区：[1]School of information science and technology,Southwest Jiaotong University,Chengdu 611756,China

出　　处：《China Communications》2025年第3期132-147,共16页中国通信(英文版)

基　　金：supported by Key Project of Sichuan Provincial Natural Science Foundation(No.2022NSFSC0043).

摘　　要：In this work,we propose a comprehensive theoretical framework for the multilevel NAND(NOT AND logic)flash memory,built upon the modified Student’s t distribution where the distortion of the threshold voltage caused by the random telegraph noise,cell-to-cell interference and data retention noise are jointly considered.Based on the superposition modulation,we build a non-orthogonal multiuser communication model where a linear mapping is conducted between the verify voltages and binary antipodal symbols.Aimed at improving the storage efficiency,we propose an unequal amplitude mapping(UAM)solution by optimizing the weighting coefficients of verify voltages to intelligently adjust the width of each state.Moreover,the uniform storage efficiency region and sum storage efficiency of different labelings with various decoding schemes are discussed.Simulation results validate the effectiveness of our proposed UAM solution where an up to 20.9%storage efficiency gain can be achieved compared to the current used benchmark scheme.In addition,analytical and simulation results also demonstrate that the successive cancellation decoding outperforms other decoding schemes for all labelings.

关 键 词：binary labelings flash memory modified Student’s t-based model superposition modulation unequal amplitude mapping 

分 类 号：TN929.5[电子电信—通信与信息系统] TP333[电子电信—信息与通信工程]