Signal Detection Under Multipath Intersymbol Interference in Staggered Bit-Patterned Media Recording Systems

Bit-patterned media recording was invented with the aim of achieving high areal density. However, bit-patterned media recording suffers from two-dimensional (2-D) interference problems, including intersymbol interference in the down-track direction and intertrack interference in the cross-track direction. The 2-D interference corrupts the readback signal and degrades the performance of bit-patterned media recording. Unlike the layout of regular-array bit-patterned media, in the layout of staggered-array bit-patterned media, islands along neighboring tracks are displaced by a half-period from islands on the main data track; hence, in terms of intertrack interference, the islands on the main data track are predominantly affected by the closest four islands on neighboring tracks. To address this problem, a proper signal detection scheme for staggered bit-patterned media recording should be developed. In this letter, we introduce a multipath soft-output Viterbi algorithm for reducing the 2-D interference in staggered bit-patterned media recording. We investigate different partial response targets and compare the performances of the one-dimensional, two-dimensional, and proposed three-path soft-output Viterbi algorithm.