In this study, we investigated the performance of perpendicular magnetic recording with squeezed
tracks. Based on spinstand signals, we developed a signal generation module to generate the
readback signals for tracks of various squeezed track width and bit length. To mitigate the drop in
bit error rate (BER) as squeezed track width decreases, we implemented the bidirectional patterndependent
noise prediction (BiPDNP) detector with low-density parity check codes. To improve the
BiPDNP detector over earlier work, we modified the log-likelihood ratio computation. Our results
show that our proposed BiPDNP detector improves the bit error rate, and allows smaller squeezed
track width and smaller bit length for the same BER performance.