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Combining Unequal Bit Islands and Coding Design for Areal Density Enhancing in Dual-Layer Bit-Patterned Magnetic Recording Systems
Author(s)
Date Issued
January 1, 2026
Type
Article
Abstract
In this work, we propose an alternating media structure for a dual-layer bit-patterned magnetic recording (DL-BPMR), in which the diameters of the bit islands in the bottom and top layers differ, with the bottom diameter 4 times that of the top. We then propose an encoding scheme that uses the larger bit island in the bottom layer for a parity bit to detect errors during decoding. Moreover, we suggest the log-likelihood ratio (LLR) flipping technique to improve decoding capability, which operates jointly during decoding. Simulation results show that at the same user density (UD), our proposed systems outperform the conventional single-layer (SL) BPMR. For instance, at a bit-error rate of 10-3 and total UDs of 2.0 or 3.2 Terabit per square inch, the proposed systems provide approximately 0.8 dB and 1.2 dB, respectively, over the conventional SL-BPMR systems.
Citation
IEEE Transactions on Magnetics, 2026