A combined Kalman filter and constant modulus algorithm beamformer for fast-fading channels

Beamformers which use only the constant modulus algorithm (CMA) are unable to track properly time-variant signals in fast-fading channels. The Kalman kilter (KF), however, has significant advantage in time-varying channels but needs a training sequence to operate. A combined CMA and KF algorithm is therefore proposed in order to utilise the advantages of both algorithms. The associated stepsize of the combination is also varied in accordance with the magnitude of the output. Simulations are presented to demonstrate the potential of this new approach.