Training symbol exploitation in CP-OFDM for DoA estimation in multipath channels

In this paper, the problem of line-of-sight (LOS) direction of arrival (DoA) estimation in multipath channels is addressed. The system that we propose is based on the well-known cyclic prefixed (CP) orthogonal frequency division multiplexing (OFDM) scheme. The algorithm searches the time instant corresponding to the first arrival path (FAP), i.e., the LOS component that brings the DoA information. A time domain channel estimator evaluates the complex amplitude of the FAP. Finally, the FAP complex amplitude of each antenna is used to estimate the DoA with a low complexity single source method. Several numerical results validate the robustness of this algorithm, also in the case when the multipath components are superimposed to the LOS component.