Adaptive Analog Echo NEXT Cancellation for 10G Ethernet
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Solution Overview
Problem
Existing echo/near-end crosstalk (NEXT) cancellation systems in Ethernet network devices face complexity in adjusting operating parameters and synchronization issues due to additional clock signals required for multiple cancellers, especially in high-speed transmission standards like IEEE 802.3an (10 GBASE-T), which increases echo/NEXT interference and reduces ADC resolution.
Innovation Solution
An adaptive analog echo/NEXT cancellation system that includes a selector for generating error control signals, an echo/NEXT cancellation module, a summing module, and an adaptive analog filter, which operates in two modes based on the presence of remotely transmitted signals to estimate and subtract echo/NEXT interference, using a multiplexer and loop filter to adjust coefficients and avoid clock mismatching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple echo/NEXT cancellers are used to reduce interference, then echo/NEXT cancellation performance is improved, but device complexity increases due to additional clock signals and parameter adjustment requirements
Solution Approach 1:
The patent combines multiple echo/NEXT cancellation functions into a single integrated canceller unit. Instead of using separate cancellers that would require multiple clock signals and independent parameter adjustments, the invention merges the cancellation functionality into one device that processes all echo and NEXT interference simultaneously, thereby reducing system complexity while maintaining cancellation effectiveness
Solution Approach 2:
The single echo/NEXT canceller is designed to perform multiple functions: it cancels both echo interference and near-end crosstalk (NEXT) interference from multiple channels. This multi-functional approach eliminates the need for separate dedicated cancellers for each interference type, reducing the overall number of components and clock signals required in the system
2Reliability
If additional clock signals are added for multiple cancellers, then cancellation coverage is improved, but synchronization difficulty increases
Solution Approach 1:
The patent uses a single clock signal for the unified echo/NEXT canceller instead of requiring multiple synchronized clock signals for separate cancellers. This merging of clocking resources eliminates synchronization challenges while the canceller maintains comprehensive coverage of all interference sources through its multi-functional design
3Productivity
If high-speed transmission is implemented, then data communication rate is improved, but echo/NEXT interference increases
Solution Approach 1:
The echo/NEXT canceller employs feedback mechanisms where the transmitted signals from multiple channels are monitored and fed back into the canceller. This feedback allows the canceller to generate accurate estimates of the echo and NEXT interference components and subtract them from the received signals, enabling high-speed transmission while actively compensating for the increased interference
Solution Approach 2:
The canceller performs preliminary anti-action by proactively generating and subtracting estimated echo and NEXT interference signals before they corrupt the received data. This preemptive cancellation approach allows the system to operate at high speeds where interference would otherwise be overwhelming, by counteracting the harmful effects before they impact signal integrity
Data Source
AI summary
A transceiver includes an analog front end (AFE) device and first, second, third, and fourth transmitters. A digital signal processor (DSP) receives digital receive signal and digital transmit signals and generates a shared error control signal and first, second, third, and fourth individual error control signals. An echo canceller system generates an estimated echo signal. First, second, and third NEXT canceller systems generate first, second, and third estimated NEXT signals, respectively, each based on the second analog receive signal and respective ones of the analog transmit signals from the second, third, and fourth transmitters during the first mode and each based on the shared error control signal, respective ones of the second, third, and fourth individual error control signals, and the respective ones of the analog transmit signals from the second, third, and fourth transmitters during the second mode.