The projection matrix method for interference cancellation

A new method to calculate a weight vector of a beamformer, called the projection matrix method, is proposed. The method calculates a projection matrix composed of the steering vector of interference or desired signal, and obtains a new spatial covariance matrix by projecting the signal covariance matrix onto the projection matrix. Then, the method finds the eigenvector corresponding to the largest eigenvalue of the new spatial covariance matrix. If this eigenvector is adopted as a weight vector of a beamformer, it is the optimal solution to maximize signal to interference plus noise ratio without requiring the inversion of the covariance matrix. The computer simulations showed that the proposed method effectively design a beamformer to cancel or attenuate interferences.