A signal subspace method for adaptive interference cancellation

An interference cancellation technique that combines a signal subspace approach with adaptive adjustment of the weight vector is derived. The weight vector is constrained to lie in a signal subspace computed by eigendecomposition of the covariance matrix of the array outputs. The weight vector is rotated to maximize the output signal-to-interference ratio. The technique does not require array calibration as in other subspace methods. This technique applies to receiver arrays for digital communication signals. The case of a BPSK signal modulating an AM transmitter is analyzed in some detail. Numerical examples illustrate the behavior of the algorithm