Write Modeling and Read Signal Processing for Heat-Assisted Bit-Patterned Media Recording

Abstract

Heat-assisted bit-patterned media recording (HABPMR) can significantly improve channel areal density due to the increased effective write field gradient provided by heat assistance and decreased media jitter offered by bit-patterned media. In this paper, an analytical write channel model, which can accurately capture the effects of Curie temperature, magnetic island position and size, anisotropy field, and write clock frequency fluctuations, is introduced and investigated for HABPMR. For read signal processing study, a read channel characterizing the media noise and reader geometry is combined with a data-dependent write channel to obtain the readback signal. In addition, the allowable write window offsets, write error rate during the write process and the bit error rate after readback as function of various noise sources are studied. Furthermore, 2-D equalization followed by the Bahl-Cocke-Jelenik-Raviv detector combined with picket-shift code is used to mitigate the 2-D interference and correct the burst errors caused by the write clock mis-synchronization. It is shown, via numerical experiments, that the proposed approach can provide significant symbol error rate performance improvement compared to a channel with conventional Reed Solomon code.