A Rate-8/9 2-D Modulation Code for Bit-Patterned Media Recording

The 2-D interference consisting of intersymbol and intertrack interferences is a major impairment in bit-patterned media recording (BPMR), especially at high-areal density (AD). One solution to mitigate the effect of 2-D interference is to apply a 2-D coding scheme on an input data sequence before recording so as to avoid some data patterns that easily cause an error at the data detection process. Nonetheless, this method usually requires many redundant bits, thus lowering a code rate. This paper proposes a rate-8/9 modulation code for a multitrack multihead BPMR system to eliminate the data patterns that lead to severe 2-D interference. Simulation results indicate that the system with the proposed code is superior to that without coding, especially when the AD is high and/or the position jitter is large. Specifically, for the system without position jitter at bit-error rate of 10^-5, the proposed system can provide 1.8 dB gain over the system without coding at the AD of 2.5 Tb/in².