author = {M. Kallinger and J. Bitzer and K.-D. Kammeyer},
  year = {2001},
  month = {Sep},
  title = {Interpolation of MVDR Beamformer Coefficients for Joint Echo Cancellation and Noise Control},
  address={Darmstadt, Germany},
  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.},
  booktitle={International Workshop on Acoustic Echo and Noise Control (IWAENC 01)}