CIF:Small:GOALI:Signal Processing and Coding for Two-Dimensional Magnetic Recording Channels

工业正在使用传统的在单个磁道上读写数据的方法接近磁盘上可能的数据存储密度的极限。这项研究考虑了另一种称为二维磁记录(TDMR)的方法，其中在传统磁盘上以二维方式读写位。TDMR中的一个关键问题是，磁盘上的给定磁性颗粒保留了写入其上的最后一位的极化；因此，如果颗粒大到足以包含两个位中心，如果它们具有不同的极性，则最旧的位将被较新的位覆盖。位由2D读取头从盘中读出。由于比特以高密度存储，从给定比特读取的信号遭受来自下行和交叉磁道方向的比特的2D码间干扰(2D ISI)。这项研究使工业能够继续改进传统的磁记录技术，而不需要对记录介质进行彻底的重新设计。研究人员研究2D信号处理和编码技术，以对抗TDMR中的颗粒覆盖和2D ISI，目标是接近最近估计的0.5bit/颗粒的信道容量。具体目标包括：1)基于三种通道模型：矩形颗粒模型、离散颗粒Voronoi模型和Voronoi模型，研究TDMR磁性颗粒通道探测器。2)将粒度信道检测与二维码间干扰检测、信道译码相结合。3)制定TDMR/ISI通道模型的容量界限。4)对照容量界限和S项目的实验数据，评估开发的算法。日立全球存储技术是西部数据的一家公司。

Industry is approaching the limit of the data storage density possible on magnetic disks with the traditional approach of reading and writing data on a single-track. This research considers an alternate approach called two dimensional magnetic recording (TDMR), wherein bits are read and written in two dimensions on conventional magnetic disks. A key problem in TDMR is that a given magnetic grain on the disk retains the polarization of the last bit written on it; hence, if a grain is large enough to contain two bit centers, the oldest bit will be overwritten by the newer one if they have different polarities. Bits are read from the disk by a 2D read head. Because bits are stored at high density, the signal read from a given bit suffers 2D intersymbol interference (2D ISI) from bits in both down and cross track directions. This research allows industry to continue to refine conventional magnetic recording technology, without radical redesign of the recording medium.The investigators study 2D signal processing and coding techniques to combat grain overwriting and 2D ISI in TDMR, with the goal of approaching the recently estimated channel capacity of 0.5 bit/grain. Specific objectives include:1) Investigate detectors for the TDMR magnetic grain channel based on three channel models: rectangular-grain model, discrete-grain Voronoi model, and Voronoi model. 2) Integrate grain channel detection with 2D ISI detection and with channel decoding. 3) Develop capacity bounds for the TDMR/ISI channel models.4) Evaluate the developed algorithms against the capacity bounds and against experimental data from the project s industrial partner Hitachi Global Storage Technologies, a Western Digital company.