An ITI-Mitigating 5/6 Modulation Code for Bit-Patterned Media Recording

Abstract

In bit-patterned media recording (BPMR), the readback signal is severely corrupted by the inter-symbol interference (ISI) and inter-track interference (ITI), especially at high recording densities, due to small bit and track pitches. One way to alleviate the ITI effect is to encode an input data sequence before recording, so as to avoid some data patterns that easily cause an error at the data detection process. This paper proposes an ITI-mitigating 5/6 modulation code for a multi-track multi-head BPMR system to eliminate the data patterns that lead to severe ITI. Specifically, each of the 5 user bits is converted into a 6-bit codeword in the form of a 3-by-2 data array, based on a look-up table. Experimental results indicate that the system with the proposed coding scheme outperforms that without coding, especially when an areal density is high and/or the position jitter is large.