New Perspectives and Insights on Distortionless Microphone Array Beamforming

This paper studies distortionless beamforming within a general signal model, where a target source is accompanied by multiple interference sources and ambient noise. In this context, the minimum variance distortionless response (MVDR) and linearly constrained minimum variance (LCMV) beamformers are commonly used techniques. However, the MVDR beamformer lacks control over residual interference sources, while the LCMV beamformer may result in insufficient noise attenuation and, in some cases, even amplify ambient noise at its output. To provide a flexible mechanism for balancing ambient noise reduction and interference suppression, we introduce a novel optimization criterion, which leads to the development of a general distortionless beamformer that includes both the MVDR and LCMV methods as special cases. The effectiveness of our proposed approach is demonstrated through various performance metrics and beampatterns.