Clock Frequency Offset Determination Using Two-Message Timing Exchange

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Solution Overview

Problem

Existing methods for determining clock frequency offsets between devices in communication technologies, such as wireless communication, often require complex calculations and additional messages, leading to increased overhead and resource consumption.

Innovation Solution

A method that involves exchanging only two messages between devices, with each message containing information about its time of departure and arrival, allowing for the calculation of clock frequency offset using a specific formula, thereby reducing overhead and resource usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If complex calculation methods and additional messages are used for determining clock frequency offset, then measurement precision is improved, but device complexity and overhead increase

Engineering Contradiction:
Improveclock frequency offset determination precisionVSAvoidsynchronization system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts only the essential timing information (time of departure and time of arrival of two messages) needed for frequency offset determination, discarding unnecessary complex calculations and additional messaging protocols. This extraction approach maintains measurement precision while significantly reducing device complexity and overhead.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of using complex forward calculations with multiple messages to determine frequency offset, the patent inverts the approach by using a simplified formula based on time differences from just two messages. This inversion resolves the contradiction by achieving precision through a fundamentally different, simpler method.

Inventive Principle:
Principle #13The other way round (Inversion)

2Measurement precision

If additional messages are exchanged for clock synchronization, then measurement precision is improved, but loss of time and overhead increase

Engineering Contradiction:
Improvetiming information accuracyVSAvoidsynchronization time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies partial action by exchanging only two messages instead of multiple messages, using just the minimum necessary communication to achieve accurate frequency offset determination. This reduces the time loss and overhead while maintaining measurement precision through the efficient use of essential timing data.

Inventive Principle:
Principle #16Partial or excessive action

3Reliability

If complex synchronization methods are used, then reliability is improved, but ease of operation deteriorates

Engineering Contradiction:
Improveclock synchronization reliabilityVSAvoidsynchronization implementation ease
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent changes the parameters of the synchronization method by using a simplified calculation formula based on time differences from two messages, rather than complex synchronization procedures. This parameter change maintains reliability through accurate frequency offset determination while significantly improving ease of operation and implementation.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4199384B1Method and apparatus for determining a clock frequency offset
Publication Date: 2025.06.18 U-BLOX
  • EP4199384B1 patent drawingFigure 1
  • EP4199384B1 patent drawingFigure 2
  • EP4199384B1 patent drawingFigure 3

AI summary

The present disclosure relates to a method (400) for determining a clock frequency offset between a first device having a first clock and at least one second device having at least one second clock, the method comprising: receiving (401), by the at least one second device, at least one first message from the first device, wherein information regarding a time of departure of the at least one first message is in the at least one first message; determining (402), by the at least one second device, a time of arrival of the at least one first message; receiving (403), by the at least one second device, at least one second message from the first device, wherein information regarding a time of departure of the at least one second message is in the at least one second message; determining (404), by the at least one second device, a time of arrival of the at least one second message; and determining (405) a clock frequency offset between the first clock and the at least one second clock based on the time of departure of the at least one first message, the time of arrival of the at least one first message, the time of departure of the at least one second message, and the time of arrival of the at least one second message. The disclosure further relates to a corresponding apparatus, system, computer program product and a computer readable storage medium.