Time Synchronization via Application-Layer Timestamping
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Solution Overview
Problem
Existing time synchronization methods for network nodes over wireless networks face challenges in accuracy and compatibility due to reliance on hardware timestamping, custom MAC frames, and encryption issues, particularly in standardized protocols like Wi-Fi, Bluetooth, and ZigBee, which limit their use in real-time systems.
Innovation Solution
A method that generates a synchronization message by modifying standard message fields, allowing timestamping at the physical layer without custom hardware, and using an application-controlled approach to ensure compatibility with existing protocols, enabling time synchronization across network nodes using standardized protocols.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If hardware timestamping is used to achieve accurate time synchronization, then time synchronization accuracy is improved, but device compatibility deteriorates because hardware timestamping is not widely available in microcontrollers and microprocessors
Solution Approach 1:
The patent replaces hardware-based timestamping mechanisms with software-based interrupt handlers. The application layer uses interrupt service routines to capture transmission and reception timestamps, substituting the mechanical/hardware timestamping system with a software-based timing system that works across diverse hardware platforms including standard microcontrollers and microprocessors.
2Measurement precision
If custom MAC frames are used for time synchronization, then time synchronization accuracy is improved, but protocol compatibility deteriorates making it impossible to work with existing protocols or third-party networking stacks
Solution Approach 1:
The patent creates a universal time synchronization method that works across multiple standardized protocols (Wi-Fi, Bluetooth, ZigBee, Thread, Ethernet) by using application-layer message exchange rather than protocol-specific MAC frame modifications. This multi-functional approach allows the same synchronization mechanism to operate across different networking stacks without requiring custom protocol implementations.
Solution Approach 2:
The patent introduces an application-layer intermediary that mediates between the physical layer transmission and the time synchronization function. Instead of modifying MAC frames at the data link layer, the application layer sends standardized messages containing synchronization data, acting as an intermediary that preserves compatibility with existing protocol stacks while enabling precise time synchronization.
3Reliability
If MAC-layer or application-layer encryption is applied to synchronization messages, then security is improved, but time synchronization accuracy deteriorates because timestamps cannot be embedded within encrypted messages
Solution Approach 1:
The patent segments the synchronization message into distinct components: unencrypted portions containing synchronization indication IDs and encrypted portions containing payload data. This segmentation allows timestamp information to be placed in unencrypted fields while maintaining the security of sensitive data, resolving the conflict between encryption and timestamp accessibility.
Solution Approach 2:
The patent extracts timestamp information from the encrypted message payload and places it in separate unencrypted fields within the message structure. By taking out the timing-critical data from the encrypted portion, the system maintains both security (encrypted payload) and synchronization accuracy (accessible timestamps in unencrypted fields).
Data Source
AI summary
A system, method and computer product for performing a time synchronization between first and second nodes includes the first node performing: generating a synchronization message, transmitting the synchronization message to the second node at a first time, taking a first timestamp in response to the synchronization message being transmitted and transmitting a timestamp message including the first timestamp to the second node at a second time; and the second node performing: receiving the synchronization message and the timestamp message from the first node, taking a second timestamp in response to the synchronization message being received, receiving the timestamp message from the first node, obtaining the first timestamp based on the received timestamp message, obtaining a timing offset between the first timestamp and the second timestamp and performing a time synchronization to the first node based on the timing offset.