Clock Tuning via Message Trust Validation
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Solution Overview
Problem
Existing communication networks face challenges in synchronizing clocks across nodes without a common clock signal, particularly in cost-effective and secure manners, especially in applications like CAN systems where external clock sources are costly and susceptible to attacks.
Innovation Solution
A circuit-based apparatus with a receiver, clock signal generator, and logic circuitry that validates the trustworthiness of messages received over a data bus, calculates timing information, and tunes the clock signal source to synchronize with remote transmitter circuits, ensuring asynchronous communication networks maintain precise clock synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an external clock source is used for all nodes on the network, then clock synchronization accuracy is improved, but system cost increases
Solution Approach 1:
Each node in the network uses its own independent clock source and autonomously synchronizes to the master node through message exchange and timing calculation, eliminating the need for expensive external clock distribution infrastructure while maintaining synchronization accuracy
Solution Approach 2:
Timing messages exchanged between nodes serve as intermediaries to transmit timing information, allowing nodes to synchronize their clocks through software-based timing protocols rather than hardware-based clock distribution
2Measurement precision
If a central clock source is used for synchronization, then clock accuracy is improved, but system security worsens due to susceptibility to attacks
Solution Approach 1:
The centralized clock synchronization function is segmented and distributed to individual nodes, each maintaining its own clock source while independently calculating timing from received messages, eliminating the single point of failure and reducing attack surface
Solution Approach 2:
Nodes pre-validate the trustworthiness of timing messages before using them for clock adjustment, assessing message authenticity and timing plausibility in advance to prevent malicious or erroneous timing data from compromising clock accuracy
3Ease of manufacture
If internal clock sources are used in each node, then system cost is reduced, but clock synchronization precision deteriorates
Solution Approach 1:
Nodes continuously exchange timing messages and calculate timing information based on round-trip time measurements, using this feedback to iteratively adjust their clock sources and maintain precise synchronization despite using inexpensive internal oscillators
Solution Approach 2:
The system dynamically adjusts clock tuning parameters based on measured timing deviations, allowing nodes to compensate for frequency drift and synchronization errors through software-based parameter optimization rather than requiring high-precision hardware
Data Source
AI summary
Aspects of the present disclosure involving tuning clock signal sources for communication. As may be implemented in accordance with one or more embodiments, trustworthiness of a message or a source of the message is validated, as indicated by data received over a data bus that communicatively couples a plurality of circuits respectively including an independent clock signal source. Data sent between the circuits can be received by adaptively sampling data that is carried by the data bus. Timing information is calculated relative to data frames of the data received over the data bus, and a clock signal source at one of the circuits is tuned in response to the validating and the calculating.