Non-linear Echo Signal Estimation for Full-Duplex Ethernet
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Solution Overview
Problem
High-speed Ethernet networks face signal distortion due to non-linearities introduced by transmit signals and echo cancellation processes in full-duplex transmission, which affect the receive signal quality.
Innovation Solution
A method for generating an estimated non-linear echo signal is developed, where data inputs are partitioned into subsets, and weight vectors and memory addresses are computed to access interpolants, allowing for the calculation of an estimated non-linear echo signal that can be summed with the receive signal to mitigate distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If full-duplex transmission is implemented to increase data rate, then network speed is improved, but non-linear signal distortion is introduced
Solution Approach 1:
The patent segments the echo cancellation process into multiple stages: linear echo cancellation followed by non-linear echo cancellation. The non-linearities are separated and processed independently using separate filter structures (e.g., LMS and NLMS algorithms), allowing each stage to address specific types of distortion without interfering with the other.
Solution Approach 2:
The patent introduces an intermediary processing stage that models the non-linear characteristics of the transmit path. This intermediary non-linear echo model acts as a mediator between the linear echo cancellation and the final receive signal, compensating for non-linear distortions before they affect the desired signal.
2Object-affected harmful factors
If linear echo cancellation is applied to remove echo signal, then echo interference is reduced, but non-linearities are introduced in the cancellation process
Solution Approach 1:
The patent converts the harmful non-linearities introduced by linear echo cancellation into a beneficial component by modeling and canceling them separately. The non-linear echo model captures these previously harmful distortions and uses them to improve overall signal quality, turning the cancellation process's weakness into a strength.
Solution Approach 2:
The patent changes the operational parameters of the echo cancellation system by introducing non-linear filter coefficients and using different adaptation algorithms (LMS vs. NLMS) for linear and non-linear components. This parameter differentiation allows the system to handle both linear and non-linear echo characteristics effectively.
3Ease of operation
If ADC is used to convert analog receive signal to digital, then signal processing capability is improved, but receive signal non-linearity is introduced
Solution Approach 1:
The patent applies preliminary non-linear compensation before the ADC conversion stage by modeling the expected non-linearities in the receive path. This preliminary action pre-corrects for ADC non-linearities, ensuring that the digital signal processing receives a cleaner input signal with reduced distortion.
Data Source
AI summary
Embodiments of a method and apparatus for generating an estimated non-linear echo signal are disclosed. One method includes receiving a plurality of data inputs. The plurality of data inputs are partitioned into subsets. A weight vector is computed for each of the subsets. A vector of addresses to memory locations is computed for each of the subsets. Values of interpolants are accessed at the memory locations (interpolation sites) based on the vector of addresses for each of the subsets. The estimated non-linear echo signal based is calculated on the values of the interpolants and the weight vector corresponding to each subset.