A Low-Complexity Cross-Domain OAMP Detector for OTFS: (Invited Paper)

Orthogonal time frequency space (OTFS) modulation is an emerging technique for reliable communications in high-mobility environments. Designing low-complexity detectors with good error rate performance is a critical research problem for OTFS. To address this problem, a low-complexity cross-domain orthogonal approximate message passing (OAMP) de-tector is proposed. In specific, by utilizing the block-diagonal property of the time-domain effective channel matrix, an SVD-based orthogonal linear estimator with low complexity is designed, followed by an orthogonal nonlinear estimator performed in the delay-Doppler domain with the help of the cross-domain message passing. We prove that the proposed detector has the potential to achieve Bayes optimality. The state evolution of the cross-domain OAMP detector is also derived. Numerical results show that the proposed detector outperforms classic detectors.