Cuba-esprit for Angle Estimation with Circular Uniform Beam Arrays

Currently, spatial signal processing for adaptive source separation and interference cancellation are extensively discussed for application in future mobile radio systems. ESPRIT-type algorithms are especially concerned because of their low arithmetic complexity and their inherent ability for superresolution estimation of the direction of arrival (DoA) [1]. The latter is also true for mobile radio vector channel sounding [5] and radio surveillance. The effectivity and ability of the applied algorithms mainly depends on the antenna array geometry. Mostly, uniform linear arrays (ULAs) are discussed because of their regular structure (which simplifies ESPRIT application) and their ability to cope with coherent sources which are typical for any mobile radio multipath environment. But, if 360° azimuth DoA coverage is claimed, at least two cross-arranged ULAs are required. Unfortunately, this is not enough to handle coherent sources. Therefore, uniform rectangular or uniform circular arrays are generally considered. On the other hand, there exist very effective, circular uniform multibeam antenna designs (circular uniform beam arrays, CUBA). To be specific, a CUBA consists of N antennas with circular symmetric beam patterns ( ) θ 0 b . The main beam directions of two adjacent elements are rotated by θ0 = 2π/N, respectively (Fig.1).