Micromagnetics-Based Analysis of Multi-Track Detection With Simplified 2-D Write Precompensation on Shingled Magnetic Recording
Micromagnetics-Based Analysis of Multi-Track Detection With Simplified 2-D Write Precompensation on Shingled Magnetic Recording
复制标题
基于微磁学的叠瓦磁记录简化二维写入预补偿多磁道检测分析
DOI：
10.1109/tmag.2016.2569530
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发表时间：
2016
影响因子：
2.1
通讯作者：
B. V. Vijaya Kumar
中科院分区：
文献类型：
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作者：
Yao Wang;B. V. Vijaya Kumar
在铺瓦式磁记录系统中，铺瓦式写入器通过重叠先前的磁道来写入窄磁道，这也会导致严重的磁道间干扰、抖动和交叉磁道方向的非线性跃迁（NLTS）。为了应对这些挑战，我们提出了一种简化的二维写入预补偿（WPC）方案，该方案调整写入电流大小而不是时间，以减轻写入过程中的二维NLTS。在所提出的WPC方案中，WPC仅针对少数似乎会导致较大媒体噪声均值和方差的特定模式实现。在训练期间，通过从固定的写场中减去电流中前一个相邻位和最近的前一个磁道的退磁场，得到正在写入电流过渡的最佳写场，并通过最小化所需场与写入场库中可用场之间的均方误差来确定最佳写电流。然后，在训练期间将产生主导退磁场的特定位和获得的最佳写入电流存储在查找表中。在写入过程中，我们可以通过将特定的先前写入的位与查找表中的位模式进行匹配来获得最佳写入电流，从而避免了计算每个写入位的退磁场和最佳写入电流。本文针对两组数据模式的预补偿，研究了两种简化的WPC方案。对于回读，研究了一种联合模式相关噪声预测（PDNP）检测器，以进一步白化二维介质噪声。仿真结果表明，在误码率为10-2的目标误码率下，与采用Bahl-Cocke-Jelinek-Raviv联合检波器检测的系统相比，所提出的简化WPC方案与联合PDNP检波器相结合，可提供高达22%的密度增益。
In shingled magnetic recording systems, a shingled writer is used to write narrow tracks by overlapping the previous tracks, which also leads to severe inter-track interference, jitter, and nonlinear transition shift (NLTS) in the cross-track direction. To deal with these challenges, we propose a simplified 2-D write precompensation (WPC) scheme that adjusts the write current magnitude instead of the timing, to mitigate the 2-D NLTS in the writing process. In the proposed WPC scheme, the WPC is only implemented for the few specific patterns that seem to cause large media noise mean and variance. During the training period, the optimum write field for current transition being written is obtained by subtracting demagnetizing field from the previous neighboring bits in the current and nearest previous tracks from a fixed write field, and the optimum writing current is determined by minimizing the mean-squared error between the needed field and the available fields within a writer field library. Then, the specific bits producing the dominant demagnetizing field and the obtained optimum writing current are stored in a lookup table during the training period. During the writing process, we can obtain the optimum writing current by matching the specific previous written bits against the bit patterns in the lookup table, avoiding the need for computing the demagnetizing field and optimum writing current for every written bit. Here, two simplified WPC schemes are investigated corresponding to precompensating two sets of data patterns. For readback, a joint pattern-dependent noise-predictive (PDNP) detector is investigated to further whiten the 2-D media noise. Simulations indicate that at the target bit error rate of 10-2, the proposed simplified WPC schemes combined with the joint PDNP detector can provide the density gains of as high as 22% compared with the system without WPC and detected with a joint Bahl-Cocke-Jelinek-Raviv detector.