Wireless Distance Measurement Using Phase Difference

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Solution Overview

Problem

Current wireless communication systems face challenges in accurately measuring distance between entities, particularly in scenarios where synchronization between transmitter and receiver is not secured, such as in vehicle-to-everything (V2X) communication, which requires precise distance measurement for reliable operations.

Innovation Solution

A method that measures distance by processing phase information of radio signals transmitted between entities using multiple frequencies, allowing for accurate distance calculation even without time synchronization, utilizing techniques like FFT operations to determine the difference in processing and reception times of these signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If time synchronization is implemented between transmitter and receiver, then distance measurement accuracy is improved, but system complexity and cost increase

Engineering Contradiction:
Improvedistance measurement accuracyVSAvoidsynchronization system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the time synchronization requirement from the distance measurement process by using phase difference measurement at a single receiver. Instead of requiring synchronized clocks between transmitter and receiver, the method measures the phase difference between signals received from multiple transmitters, thereby eliminating the need for complex inter-device synchronization while maintaining measurement accuracy.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces phase difference measurement as an intermediary approach. Rather than directly measuring time of flight which requires synchronization, the method uses phase difference at the receiver as an intermediate parameter that can be converted to distance information without requiring the transmitter and receiver to be time-synchronized.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If phase difference measurement method is used, then distance measurement can be performed without time synchronization, but measurement precision may be reduced

Engineering Contradiction:
Improveoperation without time synchronizationVSAvoiddistance measurement accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent transitions from one-dimensional time-based measurement (which requires synchronization) to two-dimensional phase-space measurement. By measuring phase differences across multiple frequencies and combining them mathematically, the system achieves accurate distance measurement without time synchronization, effectively adding a dimensional approach to the measurement problem.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent changes the measurement parameter from time of flight to phase difference. By measuring phase differences at multiple frequencies and using mathematical combination, the system achieves distance measurement accuracy comparable to time-synchronized methods while operating without synchronization. The parameter transformation allows the system to bypass the synchronization requirement while maintaining precision.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach provides improved accuracy in distance measurement, enabling reliable communication in V2X systems and other applications requiring precise distance determination, without the need for time synchronization between transmitter and receiver.

Implementation Method 1

A method and apparatus for transmitting control information in a wireless communication system supporting vehicletier aggregation (CA)

Methodology Applied
Scientific EffectElectromagnetic radiation: Electromagnetic Induction

Implementation Method 2

utilizing techniques like FFT operations to determine the difference in processing and reception times of these signals

Methodology Applied
Scientific EffectSignal processing transformation:

Implementation Method 3

measuring a phase difference between the received signal and a reference signal, wherein the reference signal is generated based on a symbol timing of the received signal

Methodology Applied
Scientific EffectPhase difference measurement:

Data Source

PatentEP3591430B1Method and device for measuring distance in wireless communication system
Publication Date: 2022.11.02 LG ELECTRONICS INC
  • EP3591430B1 patent drawingFigure 1
  • EP3591430B1 patent drawingFigure 2
  • EP3591430B1 patent drawingFigure 3

AI summary

According to one embodiment, a distance technique between a transmitter and a receiver for processing a signal in symbol units is presented. According to the embodiment, the transmitter transmits a transmission signal to the receiver through preset first and second frequencies. Then, the transmitter receives, from the receiver, a reception signal corresponding to the transmission signal. The reception signal includes a first reception component corresponding to the first frequency and a second reception component corresponding to the second frequency. The phase difference set by the receiver is applied between the phase of the first reception component and the phase of the second reception component. The phase difference is set on the basis of the difference between a reception time at which the transmission signal is received by the receiver and a processing time at which the transmission signal is processed in the receiver.