Message Feedback Interference Cancellation Aided UAMP Iterative Detector for OTFS Systems

TL;DR

This work tackles the challenge of detecting OTFS signals in high-mobility channels by introducing a message feedback interference cancellation aided unitary AMP (UAMP-MFIC) iterative detector equipped with a fast recursive scheme to control complexity. To further curb error propagation, it develops bidirectional symbol detectors, including Turbo UAMP-MFIC and Iterative Weight UAMP-MFIC, which fuse forward and backward detector outputs for enhanced performance. Empirical results show that UAMP-MFIC outperforms traditional detectors (GMP/AMP/LMMSE) in BER and convergence speed, and the bidirectional variants offer additional gains across varying SNRs and Doppler conditions. The approach is extendable to other MP-type detectors, providing a practical solution for OTFS detection in high-mobility scenarios. The contributions advance robust, scalable OTFS reception by leveraging latest feedback for interference cancellation and by jointly exploiting forward/backward information.

Abstract

The designing of efficient signal detectors is important and yet challenge for orthogonal time frequency space (OTFS) systems in high-mobility scenarios. In this letter, we develop an efficient message feedback interference cancellation aided unitary approximate message passing (denoted as UAMPMFIC) iterative detector, where the latest feedback messages from variable nodes are utilized for more reliable interference cancellation and performance improvement. A fast recursive scheme is leveraged in the proposed UAMP-MFIC detector to prevent complexity increasing. To further alleviate the error-propagation and improve the receiver performance, we also develop the bidirectional symbol detection structures, where Turbo UAMP-MFIC detector and iterative weight UAMP-MFIC detector are proposed to efficiently fuse the estimation results of forward and backward UAMP-MFIC detectors. The simulation results are finally provided to demonstrate performance improvement of our proposed detectors over existing detectors.

Figures (3)

• Figure 1: UAMP-MFIC detection for $c$-th symbol in $\left( t \right)$-th iteration.
• Figure 2: T-UAMP-MFIC detector structure.
• Figure 3: Performance analysis of message feedback interference cancellation structure for OTFS systems.