Nonlinear Echo Cancellation via 2D Look-Up Table Grid
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Solution Overview
Problem
Network switches that translate signals between different types of physical links often suffer from nonlinear echo distortion due to impedance mismatches, leading to interference and signal distortion, particularly in 10GBASE-T networks where the link partner is at distances comparable to 100 meters.
Innovation Solution
A communication device equipped with a look-up table and an echo cancellation circuit that uses a two-dimensional grid of cancellation values to compensate for nonlinear distortion by generating a cancellation signal based on current and previous signals, effectively reducing or eliminating nonlinear echo signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If signal translation is performed between different types of physical links in a network switch, then link connectivity and signal transmission are achieved, but nonlinear echo distortion and interference are generated due to impedance mismatches
Solution Approach 1:
The patent converts the harmful nonlinear echo distortion into a beneficial cancellation signal by capturing the nonlinear characteristics of the echo path and generating an equalization signal that mirrors these characteristics. This allows the harmful echo to be transformed into a useful cancellation component that, when subtracted from the received signal, eliminates the distortion and improves signal quality.
2Reliability
If traditional linear echo cancellation methods are used, then some echo compensation is achieved, but nonlinear echo distortion remains uncanceled and continues to cause interference
Solution Approach 1:
The patent changes the fundamental parameter of echo cancellation from linear to nonlinear by using a nonlinear equalization signal generator that captures the nonlinear characteristics of the echo path. This parameter change allows the system to compensate for both linear and nonlinear echo components, significantly improving cancellation effectiveness and preventing information loss from uncanceled distortion.
3Device complexity
If no echo cancellation is applied, then device complexity is minimized, but signal-to-noise ratio deteriorates due to echo interference combining with transmitted signals
Solution Approach 1:
The patent introduces a nonlinear equalization signal generator as an intermediary component that creates a cancellation signal based on the transmitted signal and characteristics of the echo path. This intermediary element enables effective echo cancellation by generating an equalization signal that mirrors the nonlinear characteristics of the echo, allowing the system to improve signal-to-noise ratio without requiring complex adaptive filtering or iterative cancellation methods.
Data Source
AI summary
Systems, methods, and other embodiments associated with echo cancellation are described. According to one embodiment, a method includes generating, in a communication device, an address to a look-up table by using a first signal and a second signal. The look-up table is a two-dimensional look-up table configured to store a plurality of cancellation values arranged in a two-dimensional grid. The method also includes producing, in the communication device, a cancellation signal according to a cancellation value in the look-up table that corresponds to the address.