Joint optimization of LCMV beamforming and acoustic echo cancellation for automatic speech recognition

For full-duplex hands-free acoustic human/machine interfaces, a combination of acoustic echo cancellation and speech enhancement is often required in order to suppress acoustic echoes, local interference and noise. In order to exploit positive synergies between acoustic echo cancellation and speech enhancement optimally, we previously presented a combined least-squares (LS) optimization criterion for the integration of acoustic echo cancellation and adaptive linearly-constrained minimum variance (LCMV) beamforming (Herbordt, W. et al., Proc. EURASIP European Sig. Process. Conf., 2004). By means of speech recognition experiments, we now illustrate the efficiency of the proposed solution in situations with high levels of background noise and with time-varying echo paths and frequent double-talk.