Abstract:The authors propose the use of a generalised array manifold for parameterised spatial signature estimation in wireless communication channels with local scattering. The array manihld commonly used for point sources is generalised to include linear combinations of the nominal array response vectors and their derivatives. The motivation behind this idea I S to obtain better estimates of the spatial signatures for direction of arrival (DOA) based signal waveform estimation. The estimators proposed exploit the orthogonality between the so-called noise and signal subspaces, leading to a separable solution for the derivative coefficients. As a result, a search is required for the DOAs only. For uniform linear arrays, the spatial signatures are shown to be approximately Vandermonde vectors with damped modes, and a closed-form estimator such as ESPRIT may be used in this case. Simulation examples are included to compare the signal estimation performance obtained using the proposed generalised manifold and the conventional array manifold.
In wireless communication scenarios, multipath propagation from local scatterers in the vicinity of mobile sources may cause angular spreading as seen from a base station antenna array. This paper studies the effects of such local scattering on direction of arrival (DOA) estimation with the MUSIC and ESPRIT algorithms.Previous work has considered rapidly time-varying scenarios, and concluded that local scattering has a minor effect on DOA estimation in such scenarios. This work considers the case in which the channel is time-invariant during the observation period. The distribution of the DOA estimates is derived, and the results show that local scattering has significant impact on DOA estimation in the time-invariant case. In addition, numerical examples are included to illustrate the analysis, and to demonstrate that the results may be used to formulate simple estimators of angular spread.
In wireless communication scenarios, local scatterers in the vicinity of the sources cause angular spreading. Herein, a parameterization of the spatial signature in the presence of local scattering is presented which applies to uniform linear arrays (ULAs). The spatial signature is shown to be approximately a Vandermonde vector for a ULA in environments with s m l l angular spread. An estimator of the spatial signature is formulated based on ESPRIT. For a simple signal waveform estimatol; the gain m y be considerable in scenarios with multiple sources, as compared with using the ideal manifold parameterized by direction of arrival (DOA).
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