Maximum likelihood direction-of-arrival estimation of BPSK modulated carriers

In mobile communication systems, phase shift keying (PSK) modulation is widely used in digital transmission schemes. Previous works have considered several maximum likelihood (ML) methods for the direction-of-arrival (DOA) estimation of generic signals reaching a phased-array of sensors. This work proposes a new ML DOA estimator designed to be used in PSK communication systems. By taking the expected value of the antenna array measured signals with respect to the modulation phases, the number of parameters to be jointly estimated is significantly reduced. Finally, the estimator performance in several simulation scenarios is presented and compared to the performance of a classic ML estimator designed for all sorts of signal models. As the proposed method robustly outperforms the classic ML estimator in all simulations, we believe this work may become an important step in the development of a more reliable hybrid space-time division multiple access system (S/TDMA).