Interpolation of MVDR Beamformer Coefficients for Joint Echo Cancellation and Noise Control

Authors: M. Kallinger, J. Bitzer, K.-D. Kammeyer
Abstract: This contribution deals with a new multi-microphone algorithm for joint acoustic echo cancellation (AEC) and noise reduction (NR). It is known that microphone arrays are useful to suppress the far-end speaker signal, if the AEC is not converged. Solutions based on adaptive beamformers are especially suited to adjust themselves to the noise field generated by the loudspeaker of a hands-free system. However, they have some problems with signal cancellation and potential interaction between the AEC and the beamformer which leads to a poor performance of the AEC. We propose a new approach with a partly adaptive beamformer which can be modified within two special cases: A superdirective beamformer and an adaptive beamformer which only becomes active as long as the AEC is diverged, e.g. after a modification of the echo path impulse response. We will introduce a criterion based on the convergence of the AEC to steer the switching between both beamformers. In order to avoid a sudden exchange of the beamformer coefficients, the new scheme interpolates between 'old' and 'new' coefficients and enables a smooth crossover by this.
Document type: Conference Paper
Publication: Darmstadt, Germany, 10. - 13. September 2001
Conference: International Workshop on Acoustic Echo and Noise Control (IWAENC 01)
Index: 116
IWAENC_2001_kallinger.pdf150 KB
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