Robust Direction-of-Arrival Estimation using Array Feedback Beamforming in Low SNR Scenarios

A new spatial IIR beamformer based direction-of-arrival (DoA) estimation method is proposed in this paper. We propose a retransmission based spatial feedback method for an array of transmit and receive antennas that improves the performance parameters of a beamformer viz. half-power beamwidth (HPBW), side-lobe suppression, and directivity. Through quantitative comparison we show that our approach outperforms the previous feedback beamforming approach with single transmit antenna, and the conventional beamformer. We then incorporate a retransmission based minimum variance distortionless response (MVDR) beamformer with the feedback beamforming setup. We propose two approaches and show that one approach is superior in terms of lower estimation error, and use that as DoA estimation method. We then compare this approach with Multiple Signal Classification (MUSIC) and Estimation of Parameters using Rotation Invariant Technique (ESPRIT) methods. While these previous methods perform poorly in low signal-to-noise-ratio (SNR) regime, we show that our method outperforms both at very low SNR levels. The results show that at SNR levels of -80 db to -10 db, the error is 80% less compared to that of MUSIC and ESPRIT.