Investigation of magnetic recording systems with higher-dimensional parity check codes
Hidetoshi Saito, Takuya Ogawa, Yoshihiro Okamoto, Hisashi Osawa · Electronics and Communications in Japan (Part II Electronics) · 2005
In recent years, various concatenation coding–decoding schemes for magnetic recording have been investigated in which the concatenation codes used are actually error correction codes. Reports that the use of these error-correction codes leads to improved efficiency characteristics of the recording process have motivated us to propose a new concatenation coding–decoding scheme. In our concept, higher-dimensional parity check codes, which are well known in the digital communications area for their strong error correction capability, are combined with partial response-equalized magnetic recording channels. We also propose a novel variable-threshold soft-decision decoding method along with the higher-dimensional parity check code that combines error detection based on parity check line vectors (informal decision) with decision-making based on comparing the confidence level of each symbol to a threshold value (formal decision). After formulating this scheme, we conducted an investigation to compare its error rate characteristics with those of a system in current use, a 16/17(0,6,6) encoding/decoding system. In this comparison we observed a clear improvement using our scheme, specifically a 3.0-dB improvement in the SN ratio required to achieve a 10−4 bit error rate. © 2005 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 89(1): 41–52, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.20113