Robust spatial filtering of coherent sources for wireless communications

This paper addresses the inter-signal coherence problem in mobile communications applications where multipath parameters, such as angle of arrival, must be estimated with an array of sensors operating in impulsive interference. We reduce the measured coherence by using the spatial smoothing approach to the structure of the measurement matrix while at the same time we mitigate the effects of the heavy-tailed background noise by employing a signed-power nonlinearity of the array data. The combination of these two processing modules gives rise to a family of robust smoothed subspace array processing methods based on fractional low-order statistics, which are able to identify all incident angles regardless of their correlation structure. The improved performance of the proposed techniques are demonstrated via Monte Carlo simulations.