Two-stage code reference beamformer in mobile communications

This paper addresses a new architecturc for hlind adaptive beamforming when dealing with Frequency Hopping (FH) modulation in cellular mobile communications systems. The proposed Code Reference Beamformer (CRB) takes advantage of the inherent frequency diversity to estimate beforehand the noise plus interference correlation matrix, which is employed as the first part of the framework. Then, a second stage is adaptively obtained without any a priori knowledge of either the direction of arrival or the array manifold. Using this information, the lirst stage is in turn readjusted and, as a result, the scheme is able to track non-stationary scenarios following the channel variations with no previous references.