Joint Four-Reader Array Equalization and Detection for a Single Track in TDMR

Abstract

Two-dimensional magnetic recording (TDMR) by shingled magnetic recording (SMR) is one of the promising technologies to achieve a magnetic recording areal density (AD) of 10 Tb/in <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . The readback signal of TDMR suffers severe 2-D inter-symbol interference (2-D ISI). At ultra-high AD, reader array is proposed to process the signals from the 2-D ISI channel because it can acquire multiple interfered signal streams simultaneously from the adjacent tracks. In this article, we propose a novel architecture for signal detection, which uses a four-reader array to recover the recording data. The auxiliary reader of the four-reader array can offer additional soft information of bits on the detected track, and this information can be used to improve the bit error rate (BER) performance. We consider three approaches to utilize the auxiliary reader and investigate the position of the auxiliary reader. Simulation results show that the proposed approach outperforms both the conventional single-reader detection and three-reader array detection. The auxiliary reader is set with an offset of 10% track pitch and can obtain a significant improvement of BER performance when the signal-to-noise rates (SNRs) of all the four readers are the same.