Quality-delay-and-computation trade-off analysis of acoustic echo cancellation on general-purpose CPU

While many previous studies have examined acoustic echo cancellation (AEC) in terms of quality, computation complexity, and implementation issues on DSP processors, this work evaluates quality-delay-computation trade-off of unconstrained frequency-domain recursive-least-square AEC algorithm on general purpose microprocessors. Specially, trade-off among echo cancellation quality, sampling delay, and computation time on Intel Pentium 4 systems is analyzed. Our quantitative analysis shows that the effectiveness of echo cancellation does not depend on availability of CPU as long as CPU can provide sufficient computational power for online real-time processing. Today´s general-purpose microprocessor-based AEC can deliver satisfactory echo cancellation quality at a computationally acceptable price (less than 5% CPU usage). On other hand, the effectiveness depends on sampling delay. And no matter how fast a microprocessor would be, it is unlikely to guarantee both smaller sampling delay and larger echo-return-loss-enhancement (ERLE) at the same time. Finally, considering possible application of general-purpose processor-based AEC in laptop, office and meeting room environments, we analyzed acoustic channel delay´s influence on both ERLE and CPU computation, showing that general- purpose microprocessor AEC´s outstanding ability in tolerating various computing environments. Our experimental results can be used to design good configuration to meet specific quality requirements in terms of quality and sampling delay.