Wireless Sensor Synchronization via Server-Side Time Correction

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Solution Overview

Problem

Existing sensor systems in wireless networks face challenges in maintaining synchronization accuracy due to clock instability, transmission delays, and CPU interruptions, which affect the precision of time synchronization across multiple sensors.

Innovation Solution

A sensor system comprising a transmission terminal with a clock oscillator, time information generator, and signal processor that determines event detection and transmission times, and a collection device that estimates event detection times by statistically processing transmission and reception times, reducing errors and improving synchronization accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If two-way communication and time correction are performed on the sensor side to achieve synchronization, then synchronization accuracy is improved, but reception power consumption and processing load increase

Engineering Contradiction:
Improvesynchronization accuracyVSAvoidreception power consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent extracts the time correction function from the sensor side and relocates it to the server side. Sensors only transmit timestamps and event data without performing correction operations, thereby reducing their processing load and power consumption. The server performs the time correction using received timestamps and synchronization information.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces a server as an intermediary between sensors and the central processing system. The server acts as a mediator that receives timestamps from sensors, performs time correction calculations, and provides corrected time information back to sensors or directly to the processing system, eliminating the need for sensors to perform complex correction operations.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If periodic reception is performed in FTSP to deliver time information to the sensor side, then synchronization accuracy is improved, but processing load and reception power increase

Engineering Contradiction:
Improvesynchronization accuracyVSAvoidprocessing load
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent employs periodic action by having the server transmit synchronization information and time correction data at regular intervals to sensors. This periodic transmission allows sensors to update their timing information without requiring continuous communication, thereby reducing overall processing load while maintaining synchronization accuracy.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent applies preliminary action by having the server perform time correction calculations in advance before sensors need the corrected time information. The server pre-calculates corrected timestamps and synchronization parameters, then transmits them to sensors, eliminating the need for sensors to perform complex real-time correction operations.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If clock instability, transmission delay, and retransmission occur in wireless networks, then synchronization accuracy deteriorates, but these factors are inherent to wireless communication

Engineering Contradiction:
Improvesynchronization accuracyVSAvoidsynchronization stability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent implements feedback mechanisms where sensors transmit their local timestamps to the server, and the server sends back corrected time information based on the observed discrepancies. This feedback loop allows the system to continuously adjust and compensate for clock instability and transmission delays, improving synchronization accuracy despite wireless communication imperfections.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent applies parameter changes by dynamically adjusting time correction values and synchronization parameters based on observed network conditions. The server modifies correction parameters in response to detected transmission delays and clock drift, allowing the system to adapt to varying wireless communication conditions and maintain synchronization accuracy.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3764621B1Sensor system, transmission terminal, time information processing device, and synchronization method
Publication Date: 2024.11.27 KK TOSHIBA
  • EP3764621B1 patent drawingFigure 1~2
  • EP3764621B1 patent drawingFigure 3~4
  • EP3764621B1 patent drawingFigure 5~6

AI summary

According to one embodiment, a transmission terminal, a time information processing device, and a synchronization method capable of improving synchronization accuracy in a wireless network are provided. According to an embodiment, a sensor system includes a sensor, a transmission terminal, and a time information processing device. The transmission terminal includes an event signal generator, an event time determiner, a communication time determiner, and a communicator. The event signal generator detects the occurrence of an event on the basis of a physical quantity detected by the sensor. The event time determiner determines a detection time of the event. The communication time determiner determines a transmission time at the time of transmission to the time information processing device. The communicator transmits time information to the time information processing device. The time information processing device includes a reception time determiner and a time information processor. The reception time determiner determines a reception time of the time information transmitted from the transmission terminal. The time information processor performs a process based on a plurality of transmission times and a plurality of reception times.