Constrained adaptive broadband beamforming algorithm in frequency domain

In this paper, the linearly constrained minimum variance (LCMV) beamforming problem is formulated in the frequency domain based on the time-domain formulation of the cost function and the constraints. We then derive a frequency-domain constrained adaptive broadband beam-forming algorithm, which has a much lower computational complexity than the time-domain algorithm, although it suffers from a slower convergence speed, as shown by simulations. It is however an attractive option when the implementation of the time-domain algorithm is prohibitive due to large computational complexity. An alternative implementation of this constrained frequency-domain algorithm using the generalised sidelobe canceller (GSC) structure is also studied.