Title: LDPC Code Design for Ultra-High Density 2D-ISI Magnetic Recording Channels

Speaker： Lingjun Kong

Date: 11^th December 15:00-16:00

Venue: 海韵教学楼504

Abstract:

New emerging magnetic recording technologies such as bit-patterned media recording (BPMR), heat (or microwave) assisted magnetic recording (HAMR) and shingled writing (SW)/two-dimensional magnetic recording (TDMR) have been proposed to push the storage density of future hard disks beyond 1Tb/in2. However, at such high recording density, many new challenges from the magnetic recording medium, read/write head as well as writing and reading channels arise. These challenges hinder the realization of Tb/in2 hard disks and should be addressed.

Optimization of low-density parity-check (LDPC) codes to approach the symmetric information rate (SIR) of two- dimensional (2D) inter-symbol interference (ISI) channels is proposed for high-density magnetic recording, such as bit-patterned magnetic recording (BPMR) and two-dimensional magnetic recording (TDMR). The code design makes use of the modified Extrinsic Information Transfer (EXIT) chart, where the optimal variable node degree is searched by selecting the best check node degree to fit the check node decoder (CND) EXIT curve to the EXIT curve of the variable node decoder (VND) curve combined with 2D detector. Simulation results show that LDPC codes with code length 104 bits optimized for 2D ISI channel corresponding to 4Tb/in2 recording density can achieve bit error rate 10−5 at signal-to-noise ratio 0.33 dB away from the SIR.

Biography:

Dr. Lingjun Kong is with the School of Computer Science & Technology, Nanjing University of Posts & Communications. He received the M.S. and the Ph.D. degree in electrical engineering from Beijing Jiaotong University in 2007 and 2011, respectively. His current research interests include coding and signal processing for data storage systems (ultra-density magnetic recording, non-volatile memory), 60G-Hz WPAN/WLAN, LTE-A, and Big Data Security.

He had been a postdoctoral fellow at InHa University of Korea from Jul. 2011 to Jan. 2012, a research fellow at Nanyang Technological University from Feb. 2012 to Nov. 2013, and a postdoctoral researcher at Hong Kong Polytechnic University from Dec. 2013 to Apr. 2014.

Dr. Kong has authored/coauthored over 20 papers on international journals and conferences，such as IEEE Transactions on Magnetics、IEEE Communications Letters and IEEE ICC.