AoA Estimation for OAM Communication Systems With Mode-Frequency Multi-Time ESPRIT Method

Radio orbital angular momentum (OAM) communications require accurate alignment between the transmit and receive beam directions. Accordingly, a key feature of OAM receivers is ability to reliably estimate angle arrival (AoA) multi-mode beams. Considering limitations existing AoA estimation techniques, in this paper, we propose an easier-to-implement method based on applying multiple times estimating signal parameters via rotational invariance techniques (ESPRIT) algorithm received training signals mode frequency domains, which denoted as mode-frequency (M-F) multi-time (MT)-ESPRIT algorithm. With method, misalignment error real channels can be greatly reduced performance approaches that ideally aligned channels.