PHY Processor Link Recovery From Low SNR

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Solution Overview

Problem

The IEEE 802.3ch standard's Energy Efficient Ethernet (EEE) feature leads to increased power consumption when transitioning to a recovery state to maintain signal-to-noise ratio (SNR) due to continuous transmission of idle symbols, even after the SNR condition has improved.

Innovation Solution

A network interface device with a PHY processor that transitions from a link recovery state to a low power state once the SNR condition ends, avoiding prolonged power consumption associated with continuous idle symbol transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the transmitter transitions to a recovery state to improve SNR by continuously transmitting idle symbols, then the signal-to-noise ratio improves, but power consumption increases significantly

Engineering Contradiction:

Improvesignal-to-noise ratioVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system dynamically transitions between LPI mode and recovery state based on real-time SNR conditions. The receiver monitors SNR and triggers state transitions, allowing the system to adapt its power consumption and transmission behavior to current channel conditions, thus resolving the contradiction between maintaining reliable communication and minimizing energy usage.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the transmission parameter state by switching between two distinct modes: LPI mode with periodic refresh symbols for energy efficiency, and recovery state with continuous idle symbol transmission for SNR improvement. This parameter change allows the system to optimize between power consumption and signal quality based on channel conditions.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the transmitter remains in the recovery state until data transmission is needed, then the SNR is maintained, but power consumption continues to increase unnecessarily

Engineering Contradiction:

Improvesignal-to-noise ratioVSAvoidenergy expenditure

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The receiver provides feedback to the transmitter about the current SNR conditions and whether the low SNR condition has ended. This feedback mechanism allows the transmitter to transition back to LPI mode when SNR has recovered, avoiding unnecessary continuous transmission and reducing energy loss while maintaining reliable communication only when needed.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The receiver continuously monitors SNR conditions and prepares to signal the transmitter when the low SNR condition has ended. This preliminary monitoring and readiness to trigger state transition ensures that the transmitter can return to low-power mode as soon as channel conditions improve, minimizing energy expenditure while maintaining communication reliability.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS11652651B1Energy efficient ethernet (EEE) link recovery from low SNR

Publication Date: 2023.05.16 MARVELL ASIA PTE LTD

AI summary

A physical layer (PHY) processor of a network interface device operates in a low power state in which a transceiver of the PHY processor device periodically does not transmit on a communication link during a plurality of quiet time slots. In response to determining a low signal-to-noise ratio (SNR) condition associated with the communication link, the PHY processor transitions to a link recovery state in which the transceiver continuously transmits idle symbols. In response to determining that the low SNR condition has ended, the PHY processor transitions from the link recovery state to the low power state.