Estimating Interference with a Two-Dimensional Viterbi Algorithm for Bit-Patterned Media Recording

Thien An Nguyen,Jaejin Lee

doi:10.3390/app12042156

Abstract

Bit-patterned media recording (BPMR) is proposed as a candidate for future magnetic data storage to overcome superparamagnetism. The distance between magnetic islands in BPMR must be reduced to increase the areal density (AD). As magnetic islands become closer, two-dimensional (2D) interference is increased, including intersymbol interference (ISI) based on the down-track direction and intertrack interference (ITI) from the cross-track direction. We propose an estimator to predict interference from neighboring (upper and lower) tracks. This estimator exploits the 2D Viterbi algorithm (VA) with reduced states. We removed the interference from the neighboring track and applied a simple 1D VA to detect the received signal. The simulation results show that our model performs better than previously proposed models.

Highlights

Mechanisms such as bit-patterned media recording (BPMR) [1], heat-assisted magnetic recording (HAMR) [2], and 2D magnetic recording (TDMR) [3,4] were developed to increase the areal density (AD) of magnetic data storage devices
The remaining pages were applied to the proposed detection model, as shown in Figure 2, to evaluate the bit error rate (BER) performance
We proposed an interference estimator that uses 2D Viterbi algorithm (VA) to improve detection performance

Summary

Introduction

Mechanisms such as bit-patterned media recording (BPMR) [1], heat-assisted magnetic recording (HAMR) [2], and 2D magnetic recording (TDMR) [3,4] were developed to increase the areal density (AD) of magnetic data storage devices. The received signal is disturbed by track misregistration (TMR) and media noise [5,6] To combat this interference, error-correcting or detection algorithms are required. We designed an interference-estimation scheme to improve detection. Nguyen and Lee developed a feedback scheme for MVA to improve ITI prediction [18]. Nguyen and Lee proposed a serial detection scheme for two 1D VA detectors along the horizontal and vertical directions [23]. Jeong and Lee proposed an ITI estimation scheme based on a neural network [28] to achieve interference with high accuracy. The simulation results show that the ITI information improves the quality of the equalizer output signal and the performance of the BPMR systems.

GPR Target

Estimating Interference

Proposed Model

BPMR Channel

Simulation and Results

Conclusions