Subspace-based techniques for 2-D DOA estimation with uniform circular array under local scattering

In mobile communication systems, local scatterers in the vicinity of the sources cause angular spreading of radiating signals as seen from a base station antenna array. Thus, the base station antenna array is typically situated on the roof of a high building away from potential multipath reflectors. The uniform circular array (UCA) geometry provides 360 degrees azimuthal coverage and also provides information on source elevation angles. We consider the problem of two-dimensional (azimuth and elevation) direction-of-arrival (DOA) estimation with UCA. In the multipath scenario, the base station antenna can receive many coherent signals that cause the array manifold to be different from the conventional array manifold model. Herein, parameters of the spatial signature in the presence of local scattering are presented which apply to UCA. Then, we present a fast searching technique to improve the efficiency of the MUSIC algorithm for two-dimensional DOA estimation. The fast signal subspace-based estimation method utilizes the ESPRIT algorithm and then adopts sequential one-dimensional searching to save computational cost. Several simulation results are included for illustration and comparison.