面向10Tb/in2级磁存储系统的二维LDPC码设计

项目名称： 面向10Tb/in2级磁存储系统的二维LDPC码设计

项目编号： No.61501250

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 无线电电子学、电信技术

项目作者： 孔令军

作者单位： 南京邮电大学

项目金额： 21万元

中文摘要： 大数据存储需求的急速增长及现有存储技术已达存储容量极限，使10Tb/in2级二维磁记录(TDMR)技术成为当前存储领域的研究热点之一。随着存储密度的提高，磁道间干扰和磁道内干扰构成的二维符号间干扰(2D-ISI)是导致存储可靠性降低、读写延迟加大的主要原因。同时，TDMR技术仍采用一维LDPC码纠错方案，二维LDPC编解码技术还没有得到相关研究。本项目拟对TDMR系统中二维LDPC码技术进行研究:首先结合2D-ISI信道，利用扩展的EXIT图方法优化码的二维度分布；重新定义陷阱集并分析环的连通性，减少由2D-ISI所导致的二维干扰范围内形成的隐形回路，基于二维度分布通过扩展的PEG和ACE算法构造二维LDPC码；最后提出基于二维变量可靠性更新的二维译码方案，减少由2D-ISI所导致的错误平层，降低读写延迟。为10Tb/in2级TDMR存储系统中纠错编码方案的选择提供技术支撑和理论参考。

中文关键词： 磁存储；二维磁记录；二维符号间干扰；LDPC码

英文摘要： According to the explosive growth of big data storage requirements and storage limit of existing storage technologies, new storage technologies, such as two-dimensional magnetic recording (TDMR), have been extensively researched in magnetic recording. With the increase of storage density, a two-dimensional inter-symbol interference (2D-ISI), which is formed by the inter-track interference (ITI) and the inter-symbol interference (ISI), becomes a major impairment for these magnetic recording systems, resulting in the decrease of storage reliability, the problem such as increased I/O latency. Meanwhile, the traditional one-dimensional error correcting code (ECC) is still adopted in the 2D storage technology, and 2D coding scheme of LDPC code has not been related research. In this project, we study the 2D-LDPC codes for the 10Tb/in2 magnetic recording system as follows: First, based on the 2D-ISI channel characteristics, we extend the extrinsic information transfer (EXIT) chart analysis method to optimize the 2D degree distributions. Secondly, according to the selected 2D degree distributions, we redefine the trapping set, reduce the invisible loop and the changes of original loop connectivity caused by 2D-ISI, and extend the PEG and ACE algorithm to design the 2D-LDPC codes. Finally, combined with the specific 2D-LDPC structures, 2D variable reliability updating based decoding scheme is proposed, so as to reduce the error floor caused by 2D-ISI, accelerate the convergence speed and reduce I/O latency. This study helps to develop the new ECC design techniques in 10Tb/in2 magnetic recording.

英文关键词： Magnetic Recording;Two-dimensional Magnetic Recording;Two-dimensional Inter-symbol Interference;Low Density Parity Check Code