A Novel Method for Partially Adaptive Broadband Beamforming

Abstract

In this paper, a novel subband-selective generalized sidelobe canceller (GSC) for partially adaptive broadband beamforming is proposed. The blocking matrix of the GSC is constructed such that its columns constitute a series of bandpass filters, which select signals with specific angles of arrival and frequencies. This results in bandlimited spectra of the blocking matrix outputs, which is further exploited by a subband decomposition prior to running independent unconstrained adaptive filters in each non-redundant subband. We discuss the design of both the blocking matrix using a genetic algorithm for an efficient sum-of-power-of-two coefficient format and the filter bank for the subsequent subband decomposition. By these steps, the computational complexity of our subband-selective GSC is greatly reduced compared to other adaptive GSC schemes, while performance is comparable or even enhanced due to subband decorrelation, as simulations indicate.