Time Synchronization System Using Latency Compensation
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Solution Overview
Problem
Conventional time synchronization systems face inaccuracies due to differences in the number of effective figures per clocking between the source and target of synchronization, and they fail to achieve power savings in battery-driven wireless communications.
Innovation Solution
A time synchronization system comprising terminal devices with a first real-time clock and a control device with a second real-time clock of greater accuracy, where the control device determines a preset time to be set to the terminal devices based on its own clock, calculating a latency time to synchronize the terminal devices without wireless clock signal reception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional time synchronization systems use RTC with different effective figures per clocking for source and target, then the system can operate with different clock resolutions, but accurate time synchronization cannot be achieved due to precision mismatch
Solution Approach 1:
The control device calculates the latency time in advance with high precision using its own high-resolution RTC, then transmits this pre-calculated latency time to terminal devices. This preliminary calculation eliminates the need for terminal devices to perform complex precision calculations, allowing accurate time synchronization even when terminal devices have lower clock resolution.
Solution Approach 2:
The control device acts as an intermediary that bridges the precision gap between high-resolution and low-resolution clocks. It performs the precision-critical calculations centrally and distributes the results, allowing terminal devices with lower precision RTCs to achieve accurate synchronization without needing to match the control device's clock resolution.
2Measurement precision
If conventional systems continuously receive clock signals via wireless communication for time synchronization, then time accuracy can be maintained, but power consumption increases for battery-driven devices
Solution Approach 1:
The control device calculates and transmits the latency time in advance to terminal devices. Once terminal devices receive this pre-calculated latency time, they can set their times accurately without needing to continuously receive clock signals via wireless communication, enabling them to enter low-power states while maintaining synchronization accuracy.
Solution Approach 2:
Terminal devices use the pre-transmitted latency time information to autonomously set their times accurately without requiring continuous external clock signals. This self-service capability allows battery-driven devices to maintain time synchronization while minimizing wireless communication and power consumption.
Data Source
AI summary
A control device 2 includes a preset time determinator 22 for determining a preset time to be set to a first real-time clock of a terminal device 3 based on a second real-time clock. The terminal device 3 includes a latency time timer 34 for clocking a lapse of a latency time which is a period of time from the terminal device 3 acquiring the preset time until the preset time being set to the first real-time clock and is calculated in a clocking accuracy having the number of effective figures greater than that of the first real-time clock, and a time setter 32 for setting the preset time to the first real-time clock when the latency time is lapsed.