Improvement in Bit Error Rate With a Combination of a Rate-3/4 Modulation Code and Intertrack Interference Subtraction for Array-Reader-Based Magnetic Recording

2022

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.

Section: Introductionmentioning

confidence: 99%

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

2022

“…By proposing a 3/4 2D modulation code that removes the ITI. Buajong and Warisarn [12] reduced the ITI in BPMR systems using an array reader. To adapt to the staggered structure of BPMR, Nguyen and Lee [13] designed an error-correcting 5/6 modulation code that can correct the errors and reduce the isolated bit.…”

Section: Introductionmentioning

confidence: 99%

“…In the detection of this GPR target, ITI information is supplied to convert the 2D detection into 1D detection with the same performance and reduced complexity. The proposed scheme extracts the ITI information supplied from multiple GPR targets instead of exploiting multi-head multitrack to subtract the ITI, as in [12,[26][27][28][29]. The proposed model exploits multiple layers of GPR targets to estimate each layer of original data.…”

Section: Introductionmentioning

confidence: 99%

One-Dimensional Detection Using Interference Estimation by Multilayered Two-Dimensional General Partial Response Targets for Bit-Patterned Media Recording Systems

2022

In bit-patterned media recording (BPMR) systems, two-dimensional (2D) interference, which includes intersymbol and intertrack interference from down- and across-track directions, respectively, increases when the distance between the islands is reduced with increasing areal density. In recent studies, a general partial response (GPR) target was often deployed with the equalizer to estimate and reduce interference. With this combination, the BPMR system becomes a promising candidate for high-density storage systems and achieves high bit error rate (BER) performance. Therefore, in this study, we investigate the detection capability while varying the form of the GPR target and implement a multilayered 2D GPR target and a detection method for improving the accuracy in estimating the interference. The simulation results demonstrate that the proposed model improves by a gain of ~1 dB compared to the previous studies.

“…Error-correcting 5/6 modulation code was introduced [8] by Nguyen and Lee to reduce 2D interference and correct errors. Buajong proposed a combination of rate-3/4 modulation code and ITI subtraction in [9] to reduce ITI. In addition, we can use an equalizer and detector with a generalized partial response (GPR) target to minimize 2D interference.…”

Section: Introductionmentioning

confidence: 99%

Modified Viterbi Algorithm with Feedback Using a Two-Dimensional 3-Way Generalized Partial Response Target for Bit-Patterned Media Recording Systems

2021

The ever-increasing demand for data in recent times has led to the emergence of big data and cloud data. The growth in these fields has necessitated that data be centrally stored in data centers. To meet the need for large-scale storage systems at data centers, innovative technology such as bit-pattern media recording (BPMR) has been developed. With BPMR technology, we are able to achieve significant improvements in high areal density (AD) of magnetic data storage systems. However, two-dimensional (2D) interference is a common issue faced with high AD. Intersymbol interference and intertrack interference occur when the distance between the islands is decreased in the down-track and cross-track, respectively. 2D interference adversely affects the performance of BPMR. In this paper, we propose an improved modified Viterbi algorithm (MVA) exploiting a feedback and a new 2D three-way form of a generalized partial response (GPR) target. The proposed MVA with feedback is superior to the previous MVA by eliminating intertrack interference (ITI) more effectively. With the three-way GPR target, the proposed algorithm achieves more stable performance compared to the previous detection algorithms for the track misregistration effect.