Two-dimensional cross-track asymmetric target design for high-density bit-patterned media recording

Author(s):  
S. Koonkarnkhai ◽  
P. Keeratiwintakorn ◽  
N. Chirdchoo ◽  
P. Kovintavewat
2020 ◽  
Vol 11 ◽  
pp. 1-5
Author(s):  
Yushu Xu ◽  
Yao Wang ◽  
Yuan Li ◽  
Lei Chen ◽  
Yumei Wen ◽  
...  

2020 ◽  
Vol 10 (17) ◽  
pp. 5738 ◽  
Author(s):  
Thien An Nguyen ◽  
Jaejin Lee

With the development of 5G technology, programs are gradually moving to cloud services. This leads to an increasing demand for storage. In the field of high-density data storage, bit-pattern media recording (BPMR) is considered a promising approach, as it can expand the data density to 4 Tb/in2. However, in high-density BPMR, bits or magnetic islands are very close to each other, leading to significant intertrack interference (ITI) from the cross-track direction and intersymbol interference (ISI) from the down-track direction. To minimize two-dimensional interference, including ITI and ISI, the serial detector method has been highly effective. However, in this method, the signal at the output of the first decoder is still a hard output. Therefore, we suggest methods to convert the output of the first detector into a soft output. Additionally, we have developed a new form of generalized partial response target to overcome the track mis-registration. The results show that our proposed methods apparently improve bit error rate performance.


2020 ◽  
Vol 10 (15) ◽  
pp. 5295 ◽  
Author(s):  
Seongkwon Jeong ◽  
Jaejin Lee

A bit-patterned media recording (BPMR) system is a type of ultrahigh-capacity magnetic storage system that can extend to an areal density of 1 terabit per square inch or higher. However, because the space between islands in the down- and cross-track directions is reduced to extend the areal density, the effect of two-dimensional interference is increased. However, using a staggered array, which is one of the possible island distributions for BPMR, helps to decrease intertrack interference. A 7/10 modulation code for a staggered BPMR is proposed to avoid the effect of two-dimensional interference and provide distance among nonidentical codewords for improving the correcting capability.


2012 ◽  
Vol 3 ◽  
pp. 4500204-4500204 ◽  
Author(s):  
N. Eibagi ◽  
J. J. Kan ◽  
F. E. Spada ◽  
E. E. Fullerton

Author(s):  
Santi Koonkarnkhai ◽  
Phongsak Keeratiwintakorn ◽  
Piya Kovintavewat

In bit-patterned media recording (BPMR) channels, the inter-track interference (ITI) is extremely severe at ultra high areal densities, which significantly degrades the system performance. The partial-response maximum-likelihood (PRML) technique that uses an one-dimensional (1D) partial response target might not be able to cope with this severe ITI, especially in the presence of media noise and track mis-registration (TMR). This paper describes the target and equalizer design for highdensity BPMR channels. Specifically, we proposes a two-dimensional (2D) cross-track asymmetric target, based on a minimum mean-squared error (MMSE) approach, to combat media noise and TMR. Results indicate that the proposed 2D target performs better than the previously proposed 2D targets, especially when media noise and TMR is severe.


2010 ◽  
Author(s):  
Yoshiyuki Kamata ◽  
Akira Kikitsu ◽  
Naoko Kihara ◽  
Seiji Morita ◽  
Kaori Kimura ◽  
...  

2014 ◽  
Vol 979 ◽  
pp. 58-61
Author(s):  
Piya Kovintavewat

High-density bit-patterned media recording (BPMR) can be obtained by reducing the spacing between data bitislands in both the along-and across-track directions, thus leading to severe intersymbol interference (ISI) and intertrack interference (ITI) because of small bit and track pitches, respectively. Here, we propose to use the graph-based detector, instead of the trellis-based detector, in iterative decoding to combat the ISI and the ITI for a multi-head multi-track BPMR system. Specifically, the readback signal is sent to the graph-based detector before iteratively exchanging the soft information with a decoder. Experimental results indicate that at low to moderate complexity, the proposed scheme outperforms the existing schemes, especially at high recording density.


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