Non-Binary Protograph-Based LDPC Codes for 2-D-ISI Magnetic Recording Channels

• Published in: IEEE transactions on magnetics Vol. 53; no. 11; pp. 1 - 5
• Main Authors: Chen, Pingping, Kui, Cai, Kong, Lingjun, Chen, Zaichun, Zhang, Mu
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.11.2017; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: 2-D inter-symbol-interference (2-D-ISI); Binary codes; Binary system; Channels; Codes; Decoding; Detectors; Error correcting codes; extrinsic information transfer (EXIT) analysis; Information transfer; Interference; Iterative decoding; Low density parity check codes; Magnetic recording; magnetic recording channels; Magnetism; Mutual information; protograph low-density parity-check (LDPC) codes; Two dimensional analysis; Two dimensional displays
• ISSN: 0018-9464; 1941-0069
• DOI: 10.1109/TMAG.2017.2697075

2-D inter-symbol-interference (2-D-ISI), consisting of ISI in the down track direction and inter-track interference along the cross-track direction, is a major factor that severely degrades the performance of ultra-high density magnetic recording systems. Due to its superior performance and the protograph structure which facilitates high-speed encoding and decoding, the protograph codes have shown a high potential to tackle 2-D-ISI. However, so far, no work has been reported on the design of non-binary protograph-based low-density parity-check (NP-LDPC) codes for 2-D-ISI channels. In this paper, we first propose a modified protograph extrinsic information transfer analysis. In conjunction with the asymptotic ensemble weight distribution analysis, they both serve as theoretical tools to analyze the performance of NP-LDPC codes designed for the 2-D-ISI channels. By further applying a fast search approach, we construct two types of NP-LDPC codes for 2-D-ISI channels. Both theoretical analyses and simulated results show that the proposed codes outperform the existing binary LDPC codes that optimized for 2-D-ISI channels as well as the non-binary quasi-cyclic LDPC code, at both low and high SNR regions.