This paper provides an analysis of optimal finite impulse response subband beamforming for speech enhancement in multipath environments. A modification of the direct path standard Wiener formulation is shown to give near-optimal performance when it comes to signal-to-noise plus interference ratio, by including coherent multipath propagation into the criterion.
Optimal FIR subband beamforming in multipath environments are analysed, and an extension of the standard Wiener solution is presented. While this formulation is shown to be equivalent to the optimal SNIR beamformer in the case of monochromatic point sources, it is also shown to be nearly optimal in SNIR sense in the case of spatially spread subband decomposed wideband sources.