Inter-Channel Decorrelation by Sub-Band Resampling for Multi-Channel Acoustic Echo Cancellation

An inter-channel decorrelation procedure is highly recommended for multi-channel acoustic echo cancellation (AEC) to directly assist adaptive filtering algorithms in overcoming the so-called “non-uniqueness” problem. Although various methods have been proposed in the past to mitigate the problem and lower the misalignment of the adaptive filter, the introduced audible distortion often limits the effectiveness of those algorithms. In this paper, we investigate in detail the decorrelation by resampling technique and a proper design strategy for sub-band resampling (SBR), which permits finely tuned, frequency specific control of the trade-off between decorrelation, measured in terms of the (magnitude-squared) coherence, and audio quality, evaluated in terms of objective speech quality measures and a subjective listening test. Our most recent study provides a deep analysis of the performance bounds of the resampling procedure by analyzing the relationship between resampling, coherence, and achievable steady-state misalignment. We provide a novel, theoretically justifiable, and perceptually motivated strategy for SBR to achieve a fast multi-channel AEC convergence rate while maintaining the highest audio quality when compared to other conventional decorrelation procedures.