Acoustic Echo Cancellation via Loudspeaker Position Beamforming
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Solution Overview
Problem
Conventional beamforming systems, particularly in speech-processing devices, face challenges in effectively isolating voice commands from noise and eliminating acoustic echoes due to variable transmission times in wireless networks, which affect the accuracy of echo cancellation.
Innovation Solution
The system employs adaptive beamforming techniques, including the use of virtual microphones and advanced filter coefficient calculations, to improve beam selection and echo cancellation by determining the position of a wireless speaker and attenuating audio output accordingly, using methods like Adaptive Reference Algorithm (ARA) processing and Minimum Variance Distortionless Response (MVDR) beamformer techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional beamforming is used to isolate voice commands, then some noise filtering is achieved, but echo cancellation accuracy deteriorates due to variable transmission times in wireless networks
Solution Approach 1:
The system dynamically adapts beamforming parameters based on detected loudspeaker positions and acoustic conditions. The beamforming filter coefficients are continuously updated to match the current spatial configuration, allowing the system to maintain accurate echo cancellation despite variable transmission times by adjusting to real-time conditions rather than relying on fixed parameters
Solution Approach 2:
The system changes beamforming parameters (filter coefficients, beam directions, and spatial filters) based on detected loudspeaker positions and acoustic environment. By adapting these parameters dynamically, the system resolves the contradiction between noise filtering and echo cancellation accuracy, achieving both goals simultaneously under varying network conditions
2Measurement precision
If adaptive beamforming with virtual microphones is implemented, then beam selection accuracy is improved, but device complexity increases
Solution Approach 1:
The system creates virtual microphones that are computational copies of physical microphone patterns. These virtual microphones simulate different spatial positions and directions without requiring additional physical hardware, thereby improving beam selection accuracy while avoiding the complexity of expanding the physical microphone array
Solution Approach 2:
The system introduces an intermediate processing layer that translates physical microphone signals into virtual microphone representations. This intermediary layer simplifies the overall system architecture by providing a standardized interface for beamforming operations, reducing the complexity of directly managing multiple physical microphones while maintaining high beam selection accuracy
3Reliability
If loudspeaker position determination is used for echo cancellation, then echo cancellation effectiveness is improved, but the system requires additional processing steps
Solution Approach 1:
The system performs preliminary detection of loudspeaker positions and acoustic conditions before executing echo cancellation. By pre-determining the spatial configuration and preparing appropriate beamforming filters in advance, the system streamlines the echo cancellation process, reducing the number of processing steps required during actual echo suppression while maintaining high effectiveness
Solution Approach 2:
The system merges loudspeaker position detection, beam selection, and echo cancellation into an integrated processing pipeline. By combining these functions that operate on the same acoustic data, the system eliminates redundant processing steps and data transfers, thereby improving echo cancellation effectiveness without proportionally increasing overall system complexity
Data Source
AI summary
Techniques for improving acoustic echo cancellation to attenuate an echo signal generated by a wireless loudspeaker are described. A relative position of the wireless loudspeaker is determined when sound from the wireless loudspeaker is determined to be the dominant sound (e.g., during output of a response to a user command or query or during speech by a far-side party during a two-way audio communication). A beam corresponding to the relative position is thereby selected for echo cancellation.