Subspace‐based techniques for 2‐d DOA estimation with uniform circular array under local scattering

Abstract

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° 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.

Impacts of three‐dimensional array over channel estimation for cell‐free massive MIMO considering spatially correlated channels

“…As with the ULA configuration, the SC is defined by the CM $$$ \mathbf{R} $$$, where the CM $$$ \mathbf{R} $$$ for the proposed UCA arrangement depends on two angles, namely the azimuth and elevation angles. In other words, when the APs (i.e., the CF network) are outfitted with the proposed UCA arrangement, the CM that describes the SC is represented using the azimuth and elevation angles 43‐46 . These two angles (i.e., azimuth and elevation angles) also offer many advantages, 47 such as permitting the array to distinguish spatially diverse users by comparing their respective azimuth and elevation angles.…”

“…In other words, when the APs (i.e., the CF network) are outfitted with the proposed UCA arrangement, the CM that describes the SC is represented using the azimuth and elevation angles. [43][44][45][46] These two angles (i.e., azimuth and elevation angles) also offer many advantages, 47 such as permitting the array to distinguish spatially diverse users by comparing their respective azimuth and elevation angles. Furthermore, when compared to the current channel models discussed in Reference 4, the proposed method is quite simple and concise.…”

DOA Estimation for Local Scattered CDMA Signals by Particle Swarm Optimization

“…As the angular spread Δ̃ ph of the h th scattered ray from the p th source arriving at the array is relatively small, a first-order Taylor expansion of in Equation (4) may be approximated as follows [ 14 ]: where and d p = ∂ a p /∂ θ p is the first derivative of the steering vector. Equation (10) is a linear model and regards as the generalized array manifold (GAM) model with scattering, which is the superposition of the p th source steering vectors and their derivatives.…”