Multi-receiver Echo Cancellation via Decorrelation Matrix
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Solution Overview
Problem
Existing multi-receiving terminal echo cancellation technologies face challenges in effectively canceling echoes in voice communication systems due to correlated receiving terminal signals, leading to low searching speed and poor sound quality, especially in variable correlation environments.
Innovation Solution
A multi-receiving terminal echo cancellation method and system that performs echo filtering on receiving terminal signals using echo filters, calculates a decorrelation matrix to buffer and decompose signals, and updates echo filter coefficients in real-time to reduce correlation between channels, eliminating the need for pre-distortion and maintaining sound quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pre-distortion approach is used to eliminate correlation between receiving terminal signals, then interference between echo cancellers is reduced, but additional hardware is required and sound quality is degraded
Solution Approach 1:
The patent replaces the mechanical pre-distortion hardware approach with a mathematical decorrelation matrix computation and signal processing approach. Instead of adding physical distortion signals through hardware, the system uses digital signal processing to compute a decorrelation matrix from buffered receiving terminal signals and applies it to eliminate correlation, thereby reducing hardware complexity while maintaining echo cancellation effectiveness
Solution Approach 2:
The patent changes the parameter approach from fixed pre-distortion coefficients to dynamically computed decorrelation matrix parameters. By buffering receiving terminal signals and computing the decorrelation matrix based on actual signal correlations, the system adapts to varying correlation conditions without requiring additional hardware, thus improving reliability while reducing device complexity
2Reliability
If pre-distortion is applied to reduce correlation between receiving terminal signals, then echo canceller interference is reduced, but replayed sound quality is significantly reduced
Solution Approach 1:
The patent substitutes the mechanical pre-distortion method that degrades sound quality with a mathematical decorrelation approach. By computing the decorrelation matrix from buffered signals and applying it to eliminate correlation between receiving terminal signals, the system achieves effective echo cancellation without introducing the sound quality degradation associated with pre-distortion
Solution Approach 2:
The patent introduces a decorrelation matrix as an intermediary between the receiving terminal signals and the echo cancellers. This matrix acts as a mathematical mediator that eliminates signal correlation without requiring physical pre-distortion, thereby maintaining sound quality while improving echo cancellation performance
3Object-affected harmful factors
If simple sum/difference operation is used for distortionless decorrelation, then replayed tone quality is protected, but it cannot support variable correlation situations or more than two channels
Solution Approach 1:
The patent transforms the static sum/difference operation into a dynamic decorrelation matrix computation that adapts to varying correlation conditions. By buffering receiving terminal signals and computing the decorrelation matrix based on actual signal correlations, the system dynamically adjusts to changing environments and supports any number of channels, not just two
Solution Approach 2:
The patent creates a universal decorrelation solution that works for any number of receiving terminal channels and any correlation condition. The decorrelation matrix approach generalizes the simple sum/difference operation, providing a multi-functional solution that maintains sound quality while adapting to variable correlation environments and supporting more than two channels
4Reliability
If receiving terminal signals are correlated in multi-channel communication, then echo canceller searching is interfered with, but searching speed is reduced and timely tracking cannot be achieved
Solution Approach 1:
The patent applies preliminary decorrelation action by computing the decorrelation matrix from buffered receiving terminal signals before the echo cancellers perform their searching. This preliminary elimination of correlation between receiving terminal signals removes the interference that would otherwise slow down the searching process, enabling faster convergence and timely tracking of echo changes
Solution Approach 2:
The patent introduces the decorrelation matrix as an intermediary that processes receiving terminal signals before they reach the echo cancellers. This mathematical mediator eliminates signal correlation, thereby removing the interference that slows down the echo canceller searching process and enabling faster, more effective echo cancellation
Data Source
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AI summary
A multi-receiving terminal echo conceltation method and a multi-receiving terminal echo cancellation system are disclosed. The present invention perfoms echo filtering on receiving terminal signals in M channels by means of echo filters to obtain filtered receiving terminal signals in M channels, and subtracts the filtered receiving terminal signals in M channels from a sending terminal signal to obtain a system output signal in which receiving terminal echoes have been cancelled; and at the same time, the present invention buffers the receiving terminal signals in M channels by means of buffers, calculates a decorrelation matrix according to each of the receiving terminal signals in M channels that are buffered within preset length, decomposes the buffered receiving terminal signals in M channels into decorrelated receiving terminal signals in M channels by means of the decorrelation matrix, and calculates update amounts of the echo filters according to the decorrelation matrix, the decorrelated receiving terminal signals in M channels and the system output signal that is fed back. The technical solutions of the present invention can support the situation of two or more receiving terminals, and are suitable for situations in which the correlation between a plurality of receiving terminal signals is variable.