Track misregistration (TMR) is one of several problems in ultrahigh areal density bit-patterned magnetic recording (BPMR) systems, in which the distances between bit-islands are very narrow in both cross-track and down-track directions. Unfortunately, distance reduction leads to intersymbol interference and intertrack interference (ITI) effects, which cause system performance degradation. To deal with these effects, we develop the optimal position of an array-reader based on a three-reader/four-track reading BPMR system that is combined with a simple two-dimensional rate-3/4 modulation code and ITI subtraction technique, which delivers the best avoidance of the ITI effect from sidetracks. We model TMR estimation and mitigation methods using readback signals that are obtained from the optimal array-readers to improve bit error rate (BER) performance. The variance-ratio of these readback signals is used to estimating the TMR levels, whereas a pair of the target's and equalizer's coefficients, accordingly designed to the estimated TMR levels, is adopted for mitigating the TMR effect. Simulation results show that our methods provide a high TMR estimation accuracy and gain a superior BER performance compared with the recording system without these techniques under the same user density.

中文翻译：

---

三阅读器/四轨阅读BPMR系统中最佳的阵列阅读器和轨道错位缓解方法

磁道未对准 (TMR) 是超高面密度位模式磁记录 (BPMR) 系统中的几个问题之一，其中位岛之间的距离在跨磁道和向下磁道方向都很窄。不幸的是，距离减少会导致符号间干扰和轨道间干扰 (ITI) 效应，从而导致系统性能下降。为了应对这些影响，我们开发了基于三读取器/四轨道读取 BPMR 系统的阵列读取器的最佳位置，该系统结合了简单的二维速率 3/4 调制码和 ITI 减法技术，这可以最好地避免侧轨的 ITI 效应。我们使用从最佳阵列读取器获得的回读信号对 TMR 估计和缓解方法进行建模，以提高误码率 (BER) 性能。这些回读信号的方差比用于估计 TMR 水平，而采用一对目标系数和均衡器系数，相应地设计为估计的 TMR 水平，用于减轻 TMR 效应。仿真结果表明，在相同用户密度下，与没有这些技术的记录系统相比，我们的方法提供了较高的 TMR 估计精度并获得了优越的 BER 性能。