Robust spatial filtering of coherent sources for wireless communications

This paper addresses the inter-signal coherence problem in mobile communica tions applications where multipath parameters, such as path angle of arriva l, must be estimated with an array of sensors operating in impulsive interf erence. We reduce the measured coherence by using the spatial smoothing app roach 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 si gned-power nonlinearity to the array data. The combination of these two pro cessing modules gives rise to a family of robust smoothed subspace array pr ocessing methods based on fractional lower-order statistics (FLOS), which a re able to identify ail incident angles regardless of their correlation str ucture. The improved performance of the proposed techniques is demonstrated via Monte Carlo simulations (C) 2000 Elsevier Science B.V. All rights rese rved.