Radio Source Localization in Multipath Channels Using EM Lens Assisted Massive Antennas Arrays

The focusing ability of the lens antennas can significantly contribute to perform precise radio localization with low complexity in a massive antennas array (MAA) system. Thus, by combining lens antennas with an MAA, we propose an approach for radio source localization through an angle of arrival (AoA) estimation in a multipath propagation scenario. We discuss two simplified antenna selection techniques to select and process the focused subsets of antennas. Then, we implement a low-complexity time of arrival estimation scheme to detect the first arrival path (FAP) that contains the actual AoA information. Finally, the FAP signal is processed to estimate the AoA very efficiently, by applying one of the traditional subspace-based methods. To further simplify the system architecture with only slight degradation in performance, we also propose a mixed analog–digital AoA estimation structure based on the application of the sum–difference signal patterns technique. The simulated root mean squared error performance curves as a function of the signal-to-noise-ratio demonstrate that the proposed approach is capable of providing good AoA estimation results while considerably reducing the overall system complexity compared with the MAA system without the lens.