Estimation of nominal directions of arrival and angular spreads of distributed sources

In this paper, we consider the problem of estimating the nominal directions of arrival (DOA) and angular spreads of multiple distributed sources. Distributed sources arise due to the presence of local scattering and impairment in wave propagation. This problem is encountered in wireless communications due to the presence of scatterers in the vicinity of the mobile or when the signals propagate through a random inhomogeneous medium. Assuming a uniform linear array (ULA), a computationally efficient estimator based on auto-regressive (AR) modeling of the lags of the covariance function is derived. The estimates of nominal DOAs and angular spreads are obtained simply by rooting a polynomial. Numerical simulations are carried out to study the performance of the suggested estimator. (C) 2003 Elsevier Science B.V. All rights reserved.