Patent ID: 8144759

Claim:
A method for complex adaptive filters used in independent component analysis (ICA) of a source signal after complex down-conversion thereof to a baseband, using mixing matrices, A/D converters and bandpass filters, to generate a baseband observation matrix X which includes said source signal and an interfering signal, the steps of the method including: (a) whitening the observation matrix X by decomposing its co-variant matrices, each component thereof having a weight vector w; (b) initializing an n th row of said weight vector w to a random vector of unit length and an iteration index k set at zero; (c) updating the real imaginary parts w r (k) and w i (k) of the weight vector by the equations: w R ⁡ ( k + 1 ) = w R ⁡ ( k ) + [ MU ] kR ⁢ ∇ BR ⁢ ( k ) ( A ) w I ⁡ ( k + 1 ) = w I ⁡ ( k ) + [ MU ] kI ⁢ ∇ BI ⁢ ( k ) ( B ) where [ MU ] k = [ μ B ⁢ ⁢ 1 ⁡ ( k ) … 0 … … … 0 … μ BM ⁡ ( k ) ] ( C ) is the convergence factor, one for each row of each weight vector, and independent for the real and imaginary components of the weight vector; and (d) solving equations (A) and (B) above by independently maximizing the total squared kurtosis of the real and imaginary components w R (k) and w l (k) of the weight vector, to optimize convergence factors [MU]kR and [MU]kl, therein obtaining continual complex weight update equations.