Simplified multi-track detection schemes using a priori information for bit patterned media recording

Abstract

Simplified multi-track detection schemes using a priori information for bit patterned magnetic recording (BPMR) are proposed in this paper. The proposed detection schemes adopt the simplified trellis diagram, use a priori information, and detect the main-track data in the along- and cross-track directions. The simplified trellis diagram, which has 4 states and 8 branches, can be obtained by setting the corner entries of the generalized partial response (GPR) target to zero and replacing the four parallel branches with a single branch. However, these simplified techniques seriously suffer from performance degradation in high density BPMR channels. To overcome the performance degradation, a priori information is used to give higher reliability to the branch metric. In addition, to fully use the characteristics of channel detection with a two-dimensional (2D) GPR target, the proposed schemes estimate a priori information and detect the main-track data in the along- and cross-track directions by using a 2D equalizer with a 2D GPR target. The bit error rate performances of the proposed schemes are compared with the previous detection schemes when areal density is 3 Tb/in2. Simulation results show that the proposed schemes with simpler structures have more than 2 dB gains compared with the other detection schemes.