A novel method for partially adaptive broadband beamforming

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 direction of arrival angles and frequencies. This results in bandlimited spectra of the blocking matrix outputs, which is further exploited by subband decomposition and discarding the low-pass subbands appropriately prior to running independent unconstrained adaptive filters in each non-redundant subband. We also discuss the design of both the blocking matrix and the filter banks 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.