Adaptive beamforming using cyclic signals in the presence of cycle frequency error

A well-known property exhibited by most man-made signals is that they generate spectral lines when they are passed through a nonlinear transform. For instance, a BPSK signal generates spectral lines at multiples of the symbol rate and the twice of the carrier frequency due to cyclostationary property. The Self-COherent REstoral (SCORE) algorithms presented by Agee, Schell and Gardner (1990), have shown to give the optimal solution for the signal extraction problem using cyclostationary statistics. However, they suffer performance degradation in the presence of cycle frequency error. This paper considers the behavior of the SCORE algorithms in the presence of cycle frequency error. Based on the theoretical analysis, we present an efficient method to alleviate the performance degradation. Simulation results are presented for showing the effectiveness of the proposed method.