Multi-Speed Ethernet PHY Wake-Up via Stored Rate
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Solution Overview
Problem
In automotive and industrial environments, efficiently waking up physical layer transceivers (PHYs) from low-power mode is challenging, especially when they support different transmission rates, as conventional methods require time-consuming handshake procedures and may lead to wake-up command mismatches, particularly when auto-negotiation is enabled.
Innovation Solution
A controller determines and stores the data transmission rate for each PHY at the physical layer, allowing for the transmission of wake-up commands at corresponding symbol rates to efficiently wake up PHYs from low-power mode, ensuring compatibility and reducing the likelihood of wake-up mode mismatches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional wake-up methods are used with auto-negotiation enabled, then PHYs can wake up from low-power mode, but time-consuming handshake procedures occur and wake-up command mismatches may happen
Solution Approach 1:
The patent stores the operating speed (100 Mb/s or 1000 Mb/s) determined during link establishment in a speed storage unit before the PHY enters low-power mode. When waking up, the controller retrieves this pre-stored speed information and uses it to generate the appropriate wake-up command symbol rate, eliminating the need for time-consuming handshake procedures and ensuring command compatibility.
2Use of energy by moving object
If PHYs enter low-power mode to conserve energy, then power consumption is reduced, but wake-up efficiency decreases due to negotiation requirements
Solution Approach 1:
The system determines and stores the operating speed before entering low-power mode, allowing rapid wake-up by directly using the stored speed information to generate wake-up commands without requiring renegotiation, thus maintaining high wake-up efficiency while conserving energy during low-power operation.
Solution Approach 2:
The controller automatically retrieves the stored speed information and generates the appropriate wake-up command without requiring external negotiation or intervention from the waking PHY, enabling self-service wake-up that improves efficiency while maintaining low power consumption during sleep mode.
3Adaptability or versatility
If different transmission rates are supported for different PHYs, then system versatility is improved, but wake-up command generation becomes complex
Solution Approach 1:
The patent separates the wake-up command generation into distinct segments based on the stored speed information. The controller uses the pre-stored speed (100 Mb/s or 1000 Mb/s) to select the appropriate symbol rate for wake-up commands, managing multi-speed complexity by segmenting the command generation process according to pre-determined speed categories.
Solution Approach 2:
The system copies the previously determined speed information into a storage unit for later retrieval. This copying mechanism allows the controller to reuse the stored speed data for generating wake-up commands, simplifying the management of multi-speed support by relying on copied historical data rather than complex real-time negotiations.
Data Source
AI summary
A method for waking up, from a low-power mode, a first communications node coupled to a second node via a first communication link, includes determining, while the first node is awake, a first transmission rate for transmitting data over the first link, storing the first rate at the second node, and selectively transmitting, from the second node to the first node, a first wake-up command at a symbol rate corresponding to the first rate. Where a third node is coupled to the second node via a second link, the method may further include determining, at the second node, while the third node is awake, a second transmission rate for transmitting data over the second link, storing the second rate at the second node, and selectively transmitting, from the second node to the third node, a second wake-up command at a symbol rate corresponding to the second rate.