A study of the MVDR filter for acoustic echo suppression

This paper studies an echo suppression approach to reducing the undesired echoes that result from the acoustic coupling between a loudspeaker and a microphone in duplex voice communication. The approach consists of four basic steps. First, both the loudspeaker and microphone signals are partitioned into small overlapping frames. Second, each frame is transformed into the short-time Fourier transform (STFT) domain. Third, a minimum variance distortionless response (MVDR) filter is designed in each subband by explicitly using the interframe signal correlation. This MVDR filter is then used to estimate the echo signal and the obtained estimate is subsequently subtracted from the microphone signal. Finally, the time-domain processed signal is constructed using the overlap-add technique with the inverse STFT. Experiments are performed and the results demonstrate that this proposed method can achieve significant amount of echo suppression in practical room environments.