Behavior of adaptive beamformers based on cyclostationary signal properties in multipath environments

The paper investigates the stationary points of a nonconvex cost function, proposed previously by the authors for adaptive beamforming, in a correlated environment. A typical multipath situation where a linear digital modulated signal is incident on the array through different paths is considered. It is shown that the points at which the minima of the cost function occur correspond to beamformer weights which provide perfect intersymbol interference removal. In effect, the beamformer combines all the multipath signals to perform a spatial equalization