The huge amount of data produced in the fifth-generation (5G) networks not only brings new challenges to the reliability and efficiency of mobile devices but also drives rapid development of new storage techniques. With the benefits of fast access speed and high reliability, NAND flash memory has become a promising storage solution for the 5G networks. In this paper, we investigate a protograph-coded bit-interleaved coded modulation with iterative detection and decoding (BICM-ID) utilizing irregular mapping (IM) in the multi-level-cell (MLC) NAND flash-memory systems. First, we propose an enhanced protograph-based extrinsic information transfer (EPEXIT) algorithm to facilitate the analysis of protograph codes in the IM-BICM-ID systems. With the use of EPEXIT algorithm, a simple design method is conceived for the construction of a family of high-rate protograph codes, called irregular-mapped accumulate-repeat-accumulate (IMARA) codes, which possess both excellent decoding thresholds and linear-minimum-distance-growth property. Furthermore, motivated by the voltage-region iterative gain characteristics of IM-BICM-ID systems, a novel read-voltage optimization scheme is developed to acquire accurate read-voltage levels, thus minimizing the decoding thresholds of protograph codes. Theoretical analyses and error-rate simulations indicate that the proposed IMARA-aided IM-BICM-ID scheme and the proposed read-voltage optimization scheme remarkably improve the convergence and decoding performance of flash-memory systems. Thus, the proposed protograph-coded IM-BICM-ID flash-memory systems can be viewed as a reliable and efficient storage solution for the new-generation mobile networks with massive data-storage requirement.

翻译：第五代(5G)网络产生的大量数据不仅给移动装置的可靠性和效率带来了新的挑战,而且还推动了新存储技术的迅速发展。由于快速存取速度和高可靠性的好处,NAND闪存已成为5G网络的一个很有希望的存储解决方案。在本文中,我们调查了利用多级电池(MLC) NAND 闪光模拟系统中的不规则绘图(IM),以迭代检测和解码进行编译(BICM-ID)的编译。 第一,我们建议加强基于程序基础的流化方法信息传输(EPEXIT)算法,以便利对IM-BICM-ID系统中的编程代码进行分析。 此外,利用EPEXIT算法,我们设计了一个简单的设计方法,用于构建一套高比率的编程代码,称为不规则的累积-蒸汽累积(IMARA)编码。 这套系统拥有极好的解码阈值和线性流-IMODRM(IM-IM-IM-IMD-IM-IM-IMR-IM-IM-IMAR-IMAR-IMAR-IML-IML-IML-IML-IML-IMD-IMD-IMD-IML-M-IMD-IMO-IMO-IMO-IMO-IML-MI-MI-MI-MI-MI-MI-MI-MI-IMO-IMO-IMO-IMO-IMO-IMO-IMO-IMO-IMO-IMS-IMSD-IMSD-IMSD-IMSD-IMSD-IMSD-IMSD-IMSDM-MI-IM-IM-IMS-IM-IM-IM-IM-IM-IM-IM-IM-IM-IM-IM-IM-IM-IM-IM-IM-IM-IM-IM-IM-IM-IM-IM-IM-IM-IM-IM-IMSDMDMDM-MI-IM-IM-IMSD-IM-MI-MI-MI-MI-IM-IM-IM-IM-IM-IM-IM-IM-IM-IM-IM-IM-IM-IMD-IM-IM-IM-IM-IM-IM-IM-IM-IM-IM-