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

由于传统的在单轨上读写数据的方法，工业界正在接近磁盘数据存储密度的极限。这项研究考虑了一种称为二维磁记录（TDMR）的替代方法，其中比特在传统磁盘上以二维方式读写。TDMR的一个关键问题是磁盘上给定的磁粒保留了写入其上的最后一位的极化；因此，如果一个颗粒大到足以包含两个比特中心，那么如果它们具有不同的极性，那么最老的比特将被新比特覆盖。位由2D读头从磁盘读取。由于比特是以高密度存储的，因此从给定比特读取的信号会受到下行和交叉磁道方向比特的二维码间干扰（2D ISI）。这项研究允许工业界继续改进传统的磁记录技术，而无需彻底重新设计记录介质。研究人员研究了二维信号处理和编码技术，以对抗TDMR中的颗粒覆盖和二维ISI，目标是接近最近估计的0.5比特/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磁颗粒通道的检测器。2)将谷物信道检测与二维ISI检测和信道解码相结合。3)制定TDMR/ISI信道模型的容量界限。4)根据容量界限和来自该项目的工业合作伙伴日立全球存储技术公司（西部数据公司）的实验数据评估开发的算法。

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.