EM lens-clustering based direction of arrival estimation in massive antenna systems

Direction of arrival (DoA) estimation in the massive antenna systems with reduced hardware and signal processing complexity is a challenging task. To address the issue, this paper presents an approach to estimate the DoA in a large number of antennas system combined with an electromagnetic (EM) lens. An EM lens has the ability to focus the received signal energy as a function of the angle of arrival (AoA) to a small subset/area of the antenna array at the base station (BS). Thus, it helps to estimate the DoA efficiently while minimizing the number of radio frequency (RF) chains and the associated signal processing costs. Moreover, by defining a cluster over a group of closely spaced subsets, the computational efforts of the DoA estimation algorithm can be further reduced.