Ethernet PHY-MAC In-Band Wake-Up via Inter-Packet Gap
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Solution Overview
Problem
Existing Ethernet networks, particularly in automotive and industrial settings, lack defined mechanisms for sleep and wake-up operations, leading to challenges in transferring wake-up/sleep commands between Medium Access Control (MAC) devices and Physical Layer (PHY) devices over the same data interface, which is not supported by standard specifications like GMII.
Innovation Solution
The solution involves using the Inter-Packet Gap (IPG) between Ethernet data frames to transmit wake-up/sleep commands over the same data interface used for data frames, eliminating the need for additional interfaces or pins between MAC and PHY devices, and ensuring compliance with existing data-interface specifications while maintaining throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wake-up/sleep commands are transmitted over a separate management interface between MAC and PHY devices, then command transfer reliability is improved, but device complexity and interface requirements increase
Solution Approach 1:
The patent merges the wake-up/sleep command transfer function with the existing data interface (GMII) between MAC and PHY devices. Instead of using a separate management interface, the invention embeds wake-up/sleep commands within the data interface's existing frame structure, specifically utilizing the Inter-Frame Gap (IFG) period. This consolidation eliminates the need for additional interface hardware while maintaining reliable command transfer through the already-established data path.
Solution Approach 2:
The data interface (GMII) is made multi-functional by enabling it to carry both traditional Ethernet data frames and wake-up/sleep commands through the same physical medium. The interface universally handles different types of traffic by interpreting the presence of specific patterns (such as extended idle periods or particular frame structures) as wake-up/sleep commands rather than data, thus serving multiple purposes without requiring separate dedicated channels.
2Adaptability or versatility
If additional interfaces or pins are added between MAC and PHY devices for wake-up/sleep commands, then command transfer capability is improved, but ease of manufacture and device complexity worsen
Solution Approach 1:
The invention combines wake-up/sleep command transfer capability with the existing data interface, eliminating the need for additional pins or interface circuits. By reusing the GMII's existing signal lines and timing structures, the system gains enhanced adaptability for power management while avoiding the manufacturing complexity and cost associated with adding new physical interfaces.
3Productivity
If wake-up/sleep commands are transmitted during data transmission periods, then throughput is maintained, but command reliability deteriorates due to data collision
Solution Approach 1:
The invention prepares for wake-up/sleep command transmission by utilizing the Inter-Frame Gap (IFG) period, which is a predetermined idle time interval that naturally occurs between consecutive Ethernet data frames. By scheduling command transmission during this pre-defined gap rather than during active data transmission, the system ensures commands are sent when the medium is already guaranteed to be free of data traffic, thus maintaining both throughput (by not extending transmission time) and reliability (by avoiding collisions).
Solution Approach 2:
The system leverages the periodic nature of Ethernet frame transmission, where regular IFG intervals occur between data frames. Wake-up/sleep commands are transmitted during these periodic gaps, synchronizing command delivery with the natural rhythm of data traffic. This periodic timing strategy ensures commands are delivered reliably without disrupting the overall data throughput, as the IFG periods are inherent to the Ethernet protocol's periodic transmission pattern.
4Device complexity
If the same data interface is used for both data frames and wake-up/sleep commands, then device complexity is reduced, but difficulty of detecting and measuring commands increases
Solution Approach 1:
The invention applies local quality differentiation by introducing specific distinguishing characteristics to wake-up/sleep commands within the data interface stream. These commands are marked with unique properties such as extended idle periods beyond the standard IFG, specific bit patterns, or particular frame structure modifications. This localized differentiation allows the receiving end to easily distinguish commands from regular data frames by examining these specific local features, thus reducing detection difficulty despite using the same interface.
Solution Approach 2:
The system employs signal characteristic changes (analogous to color changes) to differentiate wake-up/sleep commands from data frames. By modifying specific attributes of the signal during command transmission—such as extending the idle period duration, changing voltage levels, or altering frame delimiters—the receiver can easily detect and identify commands based on these distinctive signal characteristics, simplifying detection despite interface consolidation.
Data Source
AI summary
An Ethernet communication device includes a data interface and circuitry. The data interface is configured for communicating with a neighbor device. The circuitry is configured to exchange Ethernet data frames with the neighbor device over the data interface, wherein successive data frames are separated in time by an Inter-Packet Gap (IPG) having at least a predefined minimal duration, and to further exchange with the neighbor device, over the data interface, during the IPG between Ethernet frames exchanged on the data interface, a wake-up/sleep command that instructs switching between an active mode and a sleep mode.