Local Network Time Acquisition for Embedded Devices

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Solution Overview

Problem

Embedded devices without real-time clocks (RTC) or GPS functionality, and those unable to connect to NTP or GPS servers, lack an alternate mechanism to acquire current time, leading to network connection issues due to missing valid certificates.

Innovation Solution

A method where a device determines its current time status, requests and receives the current time from another device in a local network, authenticates certificates based on the received time, and establishes a network connection to join the local network, allowing it to connect to an NTP server for accurate time synchronization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If embedded devices without RTC or GPS functionality attempt to connect to NTP server, then they can acquire current time, but they cannot establish network connection due to missing valid certificates

Engineering Contradiction:
Improvetime acquisition capabilityVSAvoidnetwork connection establishment
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent applies preliminary action by having the device acquire current time from local network devices (such as smartphones or computers) before attempting to establish a network connection to the NTP server. This pre-acquisition of time information enables the device to generate valid certificates in advance, thereby resolving the certificate validation issue when connecting to the NTP server. The sequence is reversed from the conventional approach: instead of connecting first and then acquiring time, the device acquires time first and then connects.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If devices rely on external NTP or GPS servers for time synchronization, then they can obtain accurate current time, but they fail to operate in isolated environments without these servers

Engineering Contradiction:
Improvetime synchronization accuracyVSAvoidoperational capability in isolated environments
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent introduces local network devices (such as smartphones, computers, or other embedded devices) as intermediaries that already possess accurate time information from NTP or GPS servers. These intermediary devices share their time information with devices that lack direct access to external time sources. This mediator approach enables time synchronization in isolated environments while maintaining time accuracy, as the intermediary devices act as local time servers for the isolated device.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent makes the time acquisition mechanism universal by enabling devices to obtain time from multiple sources: external NTP/GPS servers when available, and local network devices when isolated. The system adapts its time acquisition method based on availability, making it versatile for both connected and isolated operational environments. This multi-functionality ensures the device can operate anywhere in the world, whether with or without external time server access.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Device complexity

If embedded devices without RTC functionality lack internal timekeeping, then they reduce hardware complexity, but they cannot acquire current time without external servers

Engineering Contradiction:
Improvehardware configurationVSAvoidtime acquisition capability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent implements self-service by enabling embedded devices to acquire time information from readily available local network resources without requiring dedicated hardware components like RTC or GPS receivers. The device uses its existing network communication capabilities to request time information from other devices on the local network, thereby serving its own timekeeping needs using resources already present in the operating environment. This eliminates the need for additional hardware while maintaining time acquisition reliability.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4221292A1Acquiring current time in a network
Publication Date: 2023.08.02 HITACHI ENERGY LTD
  • EP4221292A1 patent drawingFigure 1
  • EP4221292A1 patent drawingFigure 2
  • EP4221292A1 patent drawingFigure 3

AI summary

Exemplary of embodiments of the disclosure include a method which includes determining, by a first device, whether the first device has a current time and transmitting a request for the current time to a second device if the first device does not have the current time. The second device is in a local network. The method further includes receiving, by the first device, the current time from the second device, authenticating a certificate based on the current time received from the second device, and establishing a network connection to the local network based on the authenticated certificate.