Ethernet PHY Transceiver Precoding for Asymmetric Full-Duplex Interference
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Solution Overview
Problem
Existing Ethernet physical layer (PHY) transceivers face challenges in efficiently communicating over full-duplex wired channels, particularly in asymmetric links where interference between high-speed and low-speed signals is significant, leading to complex and costly echo cancellation techniques.
Innovation Solution
The implementation of transmitter-side precoding and receiver-side decoding in Ethernet PHY transceivers, where the transmitter precodes a data stream by summing or subtracting mutually-delayed replicas, and the receiver decodes the signal using an inverse scheme, effectively reducing interference without the need for echo cancellation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If echo cancellation techniques are used to reduce interference in full-duplex Ethernet links, then signal quality is improved, but device complexity and cost increase
Solution Approach 1:
The patent applies precoding at the transmitter side before signal transmission, where delayed versions of the transmit signal are combined with the original signal to pre-cancel expected echo interference. This preliminary action eliminates the need for complex post-reception echo cancellation processing, thereby improving signal quality while reducing receiver complexity
Solution Approach 2:
The patent introduces a delay element as an intermediary component that creates delayed replicas of the transmit signal. These delayed replicas serve as mediators to cancel echo interference by being combined with the original signal through adders or subtractors, simplifying the overall interference cancellation system
2Productivity
If asymmetric data rates are used in full-duplex Ethernet links, then productivity is improved, but interference between high-speed and low-speed signals increases
Solution Approach 1:
The patent applies different precoding strategies tailored to each direction of the asymmetric link. The high-speed transmitter uses one precoding approach while the low-speed transmitter uses another, optimizing each direction's performance while managing interference locally rather than requiring global signal coordination
Solution Approach 2:
By applying precoding before transmission in both directions, the patent preliminarily shapes the signals to minimize mutual interference. The delayed replicas are combined with original signals in advance, so that when asymmetric data streams share the full-duplex medium, their interference is already reduced, enabling high productivity without excessive cross-talk
Data Source
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AI summary
An Ethernet physical layer (PHY) transceiver (20, 24) includes a transmitter (32, 40) and a receiver (36, 44). The transmitter is configured to precode a first data stream by summing two or more mutually-delayed replicas of the first data stream, and to transmit the precoded first data stream over a full-duplex wired channel (28) to a peer Ethernet PHY transceiver. The receiver is configured to receive a second data stream from the peer Ethernet PHY transceiver over the full-duplex wired channel, and to decode the received second data stream while the transmitter concurrently is transmitting the precoded first data stream.