Acoustic Echo Cancellation via Server-Side Signal Comparison

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Solution Overview

Problem

Echoes in communication systems degrade sound quality due to network transmission delays, and existing solutions require the remote device to send sound signals back to the server, increasing data traffic.

Innovation Solution

An acoustic echo cancellation system where the local device captures both the echo and local sound, transmitting them to a server for processing, allowing simultaneous comparison and cancellation without requiring the remote device to send signals back, thus mitigating transmission delays and reducing network data load.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the remote device sends sound signals back to the server for AEC processing, then echo cancellation can be performed, but network data traffic increases

Engineering Contradiction:

Improveecho cancellation effectivenessVSAvoidnetwork data traffic

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

Instead of having the remote device send sound signals back to the server for AEC processing, the patent inverts the approach by having the local device capture and transmit only the local sound signal (including echoes) to the server. The server then performs AEC by comparing this local signal with stored remote sound signals, eliminating the need for the remote device to transmit data back to the server.

Inventive Principle:

Principle #13The other way round (Inversion)

2Reliability

If network transmission delays are present, then communication quality degrades, but existing AEC solutions cannot mitigate these delays

Engineering Contradiction:

Improvecommunication qualityVSAvoidtransmission delay

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The server performs preliminary action by storing remote sound signals in advance before they are needed for AEC processing. When the local device transmits the local sound signal (including echoes) to the server, the server can immediately compare it with the pre-stored remote sound signals, enabling real-time echo cancellation without waiting for the remote device to send signals back, thus mitigating transmission delays.

Inventive Principle:

Principle #10Preliminary action

3Loss of time

If the local device processes AEC locally, then transmission delays are minimized, but device complexity increases

Engineering Contradiction:

Improvetransmission delayVSAvoidlocal device processing complexity

Core Design Contradiction:

Loss of timeVSDevice complexity

Solution Approach 1:

The server acts as an intermediary that performs the complex AEC processing tasks. The local device only captures and transmits the local sound signal, while the server compares it with stored remote sound signals and returns the processed result. This distribution of processing tasks reduces the complexity burden on the local device while maintaining real-time performance.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS9042567B2Acoustic echo cancellation system

Publication Date: 2015.05.26 QUANTA COMPUTER INC

AI summary

An acoustic echo cancellation (AEC) system includes a remote device, for capturing a remote captured sound, a server coupled to the remote device, and a local device coupled to the server. The server transmits the remote captured sound from the remote device to the local device. The local device receives, stores and plays the remote captured sound as a local playback sound. An echo is generated from reflection of the local playback sound. The local device captures the echo and a local sound into a local captured sound, and transmits both the remote captured sound and the local captured sound to the server. The server performs AEC on the local captured sound by using the remote captured sound from the local device and transmits the AEC processed local captured sound to the remote device.