Slave Clock Synchronization in Multi-Domain TSN
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Solution Overview
Problem
Conventional IEEE standards for Ethernet switching, such as IEEE 802.1Q, are inadequate for audio and video streaming and control-type applications, particularly in automotive systems, and fail to effectively manage multiple Precision Time Protocol (PTP) clock domains, leading to delays and unsynchronized slave clocks in Time Sensitive Networks (TSN).
Innovation Solution
A method and device for synchronizing a slave clock in a TSN with multiple PTP clock domains by determining domain-specific weights based on parameters like synchronization loss and link availability, generating a weighted average control signal, and adjusting the slave clock's frequency or phase accordingly, ensuring seamless synchronization and meeting functional safety requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a slave device uses synchronization information from only one gPTP clock domain to adjust the slave clock, then the device complexity is reduced, but the synchronization reliability deteriorates when the primary clock fails
Solution Approach 1:
The patent merges synchronization information from multiple gPTP clock domains by combining domain-specific control signals into a unified control signal. This allows the slave device to utilize redundant clock sources simultaneously, improving synchronization reliability without requiring complex manual switching mechanisms.
Solution Approach 2:
The patent implements dynamic weight adjustment for different clock domains based on their operational status. When the primary clock domain fails, the system dynamically shifts weight to backup domains, enabling adaptive reliability improvement without fixed complex switching logic.
2Reliability
If the system switches from one gPTP clock domain to another in response to a clock failure, then the synchronization reliability is improved, but the synchronization delay increases during switchover
Solution Approach 1:
The patent maintains domain-specific control signals from multiple clock domains in advance, so when a failure occurs, the system can immediately use the pre-computed control signal from the backup domain without requiring time-consuming switching or recalculation operations.
Solution Approach 2:
The system continuously processes synchronization information from multiple clock domains simultaneously, ensuring that backup domains are always ready with valid control signals. This eliminates interruption or delay during failover, maintaining continuous synchronization operation.
3Reliability
If multiple clock domains are used for redundancy, then the synchronization reliability is improved, but the device complexity increases due to lack of standard guidance
Solution Approach 1:
The patent introduces domain-specific weights as adjustable parameters to control the contribution of each clock domain. By modifying these weight parameters, the system can flexibly manage multiple clock domains with simple mathematical operations, avoiding complex state management and switching logic.
Solution Approach 2:
The system continuously monitors the operational status of each clock domain and adjusts the domain-specific weights accordingly. This feedback mechanism automatically manages the complexity of multiple clock domains by using simple weight adjustments based on real-time status information.
Data Source
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AI summary
Embodiments of a method and device are disclosed. In an embodiment, a method for synchronizing a slave clock in a Time Sensitive Network (TSN) that includes multiple Precision Time Protocol (PTP) clock domains is disclosed. The method involves determining parameters related to multiple PTP clock domains, assigning domain-specific weights to the multiple PTP clock domains based on the determined parameters, generating a control signal for a clock parameter using the domain-specific weights assigned to the multiple PTP clock domains, and adjusting the clock parameter of a slave clock in response to the control signal.