Robust STFT Domain Multi-Channel Acoustic Echo Cancellation with Adaptive Decorrelation of the Reference Signals

In this paper, we present an algorithm for multi-channel acoustic echo cancellation for a high-fidelity audio reproduction system equipped with a microphone array for voice control. Since a key requirement for this type of systems is leaving the reference signals that drive the multiple loudspeakers unaltered, we propose an adaptive decorrelation procedure in the time domain before feeding these signals to the echo cancellers. This helps mitigate the so-called non-uniqueness problem arising from their high correlation. This approach offers several advantages: it is extendable to a varying number of channels, requires low computational complexity, and preserves the original reference content. The echo cancellation approach applied to the decorrelated reference signals is then based on STFT-domain robust adaptive methods that do not require double-talk detection. The combination of these two techniques makes our approach particularly desirable for multi-channel echo cancellation problems with very low signal-to-echo ratio.