Unequal protection approach for RLL-constrained LDPC coded recording system using deliberate flipping

Abstract

For alleviating Run-Length-Limited (RLL) code, the deliberate flipping approach imposes some bit errors before recording in order to meet the RLL constraint. However, high coding rate of recording system limits the correcting capability of RLL flipping errors. In this paper, we propose a decoding scheme using Unequal Protection (UEP) Low-Density Parity-Check (LDPC) code by means of regular inter-leaver to confine the occurrence of flipping errors into a section of codeword. Specified section with flipping errors are attributed to the high degree nodes with high error protection capability. Iterative decoding within several iterations can solve the hard errors at the reading side. Experimental results reveal that our approach has a better BER performance compared to the recording system with RLL code. Experimental results show that our proposed scheme can efficiently exploit the correction capability to recover flipping bits.