Raytheon E-systems, Inc.

Joseph Patrick Kennedy, Jr

Mark C Sullivan

Phillip Donald Harvey

A signal processing system and method for improving reception of plural signals received at an antenna array in a wireless communication system by increasing the carrier-to-interference plus noise ratio and by decreasing signal envelope variance of each of the plural signals using single or multiple stage subspace projection and a constant modulus beamformer. Each of the stages separate and optimize one of the signals and projects the remaining signals (if present) to the subspace of the next stage. In the method and system the plural signals received at each antenna are converted to baseband in a wideband RF downconverter. Received signals are thereafter provided in digital form to the constant modulus beamformer where each stage of the beamformer separates one of the plural signals from a stage input so that a stage output has the remaining ones of the plural signals, and projects the stage output onto a subspace of the remaining signals in the next stage. The subspace basis is given by the set of eigenvectors associated with the N largest eigenvalues of the spatial covariance matrix R. This basis is preferably found iteratively using a linearized stochastic gradient ascent (SGA) algorithm.

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Great Falls, VA, United States of America

Joseph Patrick Kennedy, Jr