Frequency Calibration Method for Wireless Devices

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Solution Overview

Problem

Wireless communication devices face challenges in achieving precise frequency synchronization due to strict carrier frequency accuracy requirements, particularly in high-speed environments, where existing methods are costly and inefficient, especially in asymmetric network environments.

Innovation Solution

A frequency calibration method that uses packet transmission between an electronic device and a time server to calculate and adjust clock frequency, accounting for both symmetric and asymmetric network conditions, without requiring extensive computation or additional hardware, by analyzing time intervals and propagation delays.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a high precision oscillator is used to meet carrier frequency accuracy requirements, then frequency synchronization accuracy is improved, but device cost increases

Engineering Contradiction:
Improvecarrier frequency accuracyVSAvoiddevice cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent replaces the mechanical/physical high-precision oscillator system with a software-based frequency calibration system. The base station uses packet transmission timing measurements and computational algorithms to calculate frequency offsets, substituting hardware precision requirements with software processing capabilities. This allows standard oscillators to be used instead of expensive high-precision ones, while achieving the required ±0.1ppm frequency accuracy through mathematical correction.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If complex frequency calibration algorithms are used to achieve precise synchronization, then frequency accuracy is improved, but processor overhead increases

Engineering Contradiction:
Improvefrequency synchronization accuracyVSAvoidcomputational complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts and separates the frequency calibration function into independent measurement and correction components. It measures packet transmission timing offsets separately, calculates frequency deviations from these measurements, and applies corrections independently. This modular approach simplifies the overall algorithm complexity while maintaining high synchronization accuracy, as each component can be optimized separately rather than requiring a complex monolithic solution.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent performs preliminary frequency offset measurements using packet timing data before applying corrections to the carrier frequency. By pre-calculating the frequency deviation from timing offsets and preparing correction values in advance, the system reduces real-time computational complexity during actual frequency synchronization operations, thereby lowering processor overhead while maintaining accuracy.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If frequent packet exchanges are used for frequency calibration, then calibration accuracy is improved, but network bandwidth consumption increases

Engineering Contradiction:
Improvefrequency calibration accuracyVSAvoidnetwork bandwidth consumption
Core Design Contradiction:
Measurement precisionVSLoss of energy

Solution Approach 1:

The patent implements periodic frequency calibration by exchanging measurement packets at regular intervals rather than continuously. The base station sends calibration packets periodically, measures timing offsets, calculates frequency corrections, and applies them at scheduled moments. This periodic approach maintains adequate calibration accuracy for frequency synchronization while significantly reducing network bandwidth consumption compared to continuous packet exchanges, as the system only communicates when calibration updates are needed.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP3010168B1Frequency calibration method
Publication Date: 2019.10.23 SERCOMM CORP
  • EP3010168B1 patent drawingFigure 1~2
  • EP3010168B1 patent drawingFigure 3
  • EP3010168B1 patent drawingFigure 4

AI summary

A frequency calibration method for an electronic device is provided. The frequency calibration method includes the following steps: transmitting a first request packet to a time server at a device first time instant; receiving a first response packet responding the first request packet from the time server at a device second time instant; transmitting a second request packet to the time server at a device third time instant, wherein a device first time interval is equal to a difference between the device first time instant and the device third time instant; receiving a second response packet responding the second request packet from the time server at a device fourth time instant, wherein a device second time interval is equal to a difference between the device second time instant and the device fourth time instant.