A Combination Approach for 2-D Interference Channel Based on Factor Graph in BPMR System

High areal density in bit-patterned media recording (BPMR) systems encounters several challenges, such as two-dimensional (2-D) interference channels and media noises in the presence of severe fluctuations. To combat the effects of the 2-D interference channel, a factor graph-based detector (FGB) is one of the promising detectors for the 2-D detection that can mitigate the channel impairment. In this paper, we propose an improvement of factor graph decoding for 2-D interference channels of the BPMR system. The 2-D interference channel is separated into the two targets that are the upper triangular target and the lower triangular target. After that, the joint outputs are averaged for each detector. The simulation results show that the proposed FGB detector method achieves lower bit error rate (BER) performances than both the conventional FGB detector and the 2-D FGB detector on the BPMR system with an areal density of 3 and 4 Tb/in².