Direction-of-Arrival Estimation in the Presence of Phase Noise

This letter proposes a robust direction-of-arrival (DoA) estimator in the presence of phase noise (PN). For a multi-antenna system with independent oscillators, the received signals will be corrupted by multiple independent PN sources, resulting in severe performance degradation of the DoA estimator, especially for millimeter-wave systems. However, due to the time-varying nature of PN, the number of associated unknowns grows with the size of the snapshots, making the calibration challenging. To tackle this problem, we use a piece-wise linear model to approximate PN so that the number of associated unknowns can be reduced. Then we estimate the DoA and the PN parameters iteratively via a nonlinear least squares estimator. To evaluate the effectiveness of the proposed scheme, the Cramer-Rao lower bound (CRLB) of the DoA estimation in the presence of PN is derived. Numerical results show a significant performance improvement of the proposed DoA estimator compared to the results without calibration.