Applications of cumulants to array processing. III. Blind beamforming for coherent signals

For pt.II see ibid., vol.43, no.7, p.1663-7, 1995. We provide a cumulant-based blind beamforming method for recovery of statistically independent narrowband source signals in the presence of coherent (or perfectly correlated) multipath propagation. Our method is based on the fact that for a blind beamformer, the presence of coherent multipaths is equivalent to the case of independent sources with a different steering matrix. Our approach is applicable to any array configuration having unknown response. Signal sources must have nonzero fourth-order cumulants. There is no need to estimate the directions of arrival. Our method maximizes signal-to-interference plus noise ratio (SINR). A comparable result does not exist using just second-order statistics.