Decoding for magnetic recording media with overlapping tracks

Increasing recording track density by allowing overlap of adjacent tracks can lead to a substantial increase in storage density for magnetic recording. However, track overlap may cause severe intertrack interference (ITI) and result in loss of performance. Sophisticated signal processing techniques must then be used to recover this loss. We study the use of joint equalization and decoding for magnetic recording with overlapping tracks. We present results for a scheme that uses minimum mean-squared-error (MMSE) equalization in conjunction with error-correction coding using low-density parity-check (LDPC) codes. The recording process is simulated using a micromagnetic model for longitudinal magnetic recording. We use a three-track system to study the track overlap. The outer two tracks are allowed to overlap on the middle track to simulate ITI. Bit-error rate simulations show that the MMSE-LDPC decoding scheme incurs negligible loss when each of the outer tracks overlaps 10% on the middle track. By varying the recording parameters, the tradeoff between storage density and performance is also studied. We show that by a judicious choice of LDPC codes, a recording with track overlap can have better performance than when there is no overlap. Hence, a higher storage density can be obtained without loss in performance.