Robust DOA estimation and tracking for integrated sensing and communication massive MIMO OFDM systems

In this paper, we propose a robust direction-of-arrival (DOA) estimation and tracking scheme for a massive multiple input multiple output (MIMO) orthogonal frequency-division multiplexing (OFDM) system using integrated sensing and communication (ISAC). First, a frame structure is designed to enable integrated DOA estimation and tracking, as well as data transmission. Then, coherent combining and multipath combining methods are proposed as pilot signal preprocessing methods for robust DOA estimation and tracking. Finally, for ISAC massive MIMO-OFDM systems, a fast Fourier transform (FFT) algorithm-based robust DOA estimator design is proposed, including a preamble-based initial DOA estimation scheme and an embedded pilot-based DOA tracking scheme. The simulation results demonstrate that the proposed robust DOA estimation and tracking method can obtain accurate DOA estimation even when the signal-to-noise ratio is low. Furthermore, the estimation performance outperforms the conventional multiple signal classification (MUSIC) and estimation of signal parameters via rotational invariance technique (ESPRIT) methods.