Reduced-Complexity Turbo Equalization for High-Density Magnetic Recording Systems

This paper considers a decision-feedback-equalizer (DFE)-based soft decision detector as an alternative for the Bahl–Cocke–Jelinek–Raviv (BCJR) front-end for a coded magnetic recording channel. In previous work, a bidirectional-arbitrated DFE (BAD) was shown to perform in between a BCJR detector and a minimum mean-square error DFE. We propose a soft-output BAD (S-BAD) which takes advantage of the original structure and is suitable for iterative decoding when used with outer codes. We show that with a convolutional code as an outer code, S-BAD performs close to higher complexity detectors.