Soft-Decision Output Encoding/Decoding Algorithms of a Rate-5/6 CITI Code in Bit-Patterned Magnetic Recording (BPMR) Systems

Abstract

Nowadays, the growing demand for recording storage is steadily increasing. At high areal densities in magnetic recording system major cause of small bit and track width as a way to overcome 2D interference, which consisting of inter-symbol interference (ISI) and intertrack interference (ITI). One way to improve performance of this problem, we need to be handled by using 2D modulation code with a simulation model in a bit-patterned media recording (BPMR). The previous research of modulation codes such as constructive ITI (CITI) code was created based on the hard decision. In this work; however, we propose a soft decision output decoding algorithm of a rate-5/6 constructive ITI (CITI) code to utilize it in an iterative decoding process. The proposed use the log-likelihood ratio (LLR) algebra in Boolean logic mappings with a modified 2D soft-output Viterbi algorithm (SOVA) detector. When we consider the BER=10{6}, simulation results show that the proposed encoding and decoding schemes offer approximately 1.5 and 3 dB gains over the conventional coded system at 2 and 3 Tera-bit per square inch (Tb/in2), respectively. In addition, the gains of approximately 0.2 and 1.5 dBs are obtained over that of a hard decision decoding of modulation code regarding with the same code rate and the same areal density, respectively.