Full-Duplex Ethernet Link Training with Concurrent Equalizer Adaptation
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Solution Overview
Problem
Existing full-duplex communication systems face challenges in efficiently training PHY transceivers due to varying channel and echo characteristics, requiring complex coordination and potential communication halts in asymmetric data rates.
Innovation Solution
Concurrent training of equalizers and echo cancelers in PHY transceivers using independent clocks and the same modulation scheme for both transmission and reception, allowing for symmetrical link training without silent periods and complex state machines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional sequential training is used for full-duplex PHY transceivers, then coordination complexity is reduced, but link training time and power consumption increase
Solution Approach 1:
The patent implements concurrent training where both PHY transceivers perform equalizer and echo canceler training simultaneously using independent clocks, eliminating idle periods and continuous coordination overhead. This allows useful training action to continue without interruption in both directions, reducing total training time while maintaining manageable complexity through standardized training sequences.
Solution Approach 2:
The patent uses preliminary training sequences transmitted before actual data communication to pre-train equalizers and echo cancelers. These preliminary actions include sending known training patterns that allow receivers to adapt their parameters in advance, ensuring ready-to-use trained parameters when full-duplex communication begins, thus reducing operational delays.
2Adaptability or versatility
If independent clocks are used for training signals in full-duplex mode, then data rate flexibility is improved, but clock synchronization complexity increases
Solution Approach 1:
The patent segments the full-duplex training process into independent clock domains for each direction. Each PHY transceiver uses its own independent clock for generating and processing training sequences, allowing separate optimization of each direction's data rate. This segmentation eliminates the need for complex bidirectional clock synchronization while maintaining flexibility.
Solution Approach 2:
The patent introduces an intermediary clock recovery and resampling mechanism that bridges independent clocks. The receiver recovers the transmitter's clock from incoming training sequences and uses it for resampling and processing, acting as an intermediary that enables independent clock operation while ensuring proper synchronization for echo cancellation and equalization.
3Use of energy by moving object
If concurrent training of equalizers and echo cancelers is implemented, then power efficiency is improved, but training accuracy may deteriorate due to signal interference
Solution Approach 1:
The patent implements periodic training sequences with distinct patterns for equalizer training and echo canceler training. By alternating or interleaving these periodic training signals in time, the system maintains concurrent operation (improving power efficiency) while ensuring that each training function receives dedicated signal periods free from interference (maintaining accuracy).
Solution Approach 2:
The patent applies different local signal characteristics to different training functions. Equalizer training uses specific signal patterns optimized for channel equalization, while echo canceler training uses different patterns optimized for echo path identification. This local differentiation of signal quality allows concurrent operation without mutual degradation of training accuracy.
Data Source
AI summary
A communication system includes a first physical-layer (PHY) transceiver and a second PHY transceiver. The first PHY transceiver includes (i) a first transmitter and (ii) a first receiver including a first equalizer. The second PHY transceiver includes (i) a second transmitter and (ii) a second receiver including a second equalizer. The first PHY transceiver and the second PHY transceiver are configured to communicate with one another over a full-duplex link, including training the first equalizer on a second training signal transmitted from the second PHY transceiver, and concurrently training the second equalizer on a first training signal transmitted from the first PHY transceiver.

