Robust microphone arrays using subband adaptive filters

A new adaptive beamformer which combines the idea of subband processing and the generalized sidelobe canceller structure is presented. The proposed subband beamformer has a blocking matrix that uses coefficient-constrained subband adaptive filters to limit target cancellation within an allowable range of direction of arrival. Simulations compare the fullband adaptive beamformer and the subband adaptive beamformer show that the subband beamformer has better performance than the fullband beamformer when the input signals to the microphone array are coloured. In reverberant environments, also, the proposed subband beamformer performs better than its fullband counterpart.