OAM Antenna Displacement Correction via Channel Response Evaluation

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Solution Overview

Problem

Antennas in OAM multiplexing communication systems face challenges in maintaining orthogonality due to displacement, leading to inter-mode interference, which is difficult to correct accurately without precise adjustment methods.

Innovation Solution

An antenna displacement correction method and device that estimate and correct displacement using an evaluation function based on theoretical and measured channel responses, employing discrete Fourier transforms and inverse transforms to minimize differences in channel responses, allowing for precise alignment of transmitting and receiving antennas.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If antenna displacement is not corrected, then the system structure remains simple, but inter-mode interference occurs due to broken orthogonality between OAM modes

Engineering Contradiction:
Improveorthogonality between OAM modesVSAvoidcorrection system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements feedback by measuring the actual channel response and comparing it with theoretical channel responses corresponding to different displacement amounts. The displacement amount estimation unit uses this comparison to determine the actual displacement, which then feeds back to correct the antenna positioning, thereby maintaining orthogonality between OAM modes

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces complex mechanical adjustment systems with signal processing-based displacement estimation. Instead of using sophisticated mechanical positioning mechanisms, the system uses channel response measurements and signal processing algorithms to estimate and correct displacement, reducing mechanical complexity while maintaining alignment accuracy

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

2Measurement precision

If manual adjustment is used to correct antenna displacement, then the device complexity is low, but the adjustment precision is insufficient to remove fine displacement

Engineering Contradiction:
Improvedisplacement measurement accuracyVSAvoidcorrection device complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces manual mechanical adjustment with automated signal processing-based displacement estimation. The system uses channel response measurements and compares them with theoretical models to automatically determine displacement amounts, achieving fine measurement precision without complex mechanical adjustment devices

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

Solution Approach 2:

The system performs self-diagnosis and self-correction by automatically measuring channel responses, estimating displacement amounts, and applying corrections without requiring manual intervention. This self-service capability achieves high precision while keeping the device structure relatively simple

Inventive Principle:
Principle #25Self-service

3Measurement precision

If iterative translation and rotation methods are used for beam alignment, then alignment precision is enhanced, but the complexity of the alignment process increases

Engineering Contradiction:
Improvealignment precisionVSAvoidalignment process complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the essential displacement information from complex channel responses by comparing measured responses with theoretical responses for different displacement amounts. This extraction approach achieves high alignment precision by focusing on the critical displacement parameter rather than performing full iterative translation and rotation adjustments

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP3780428B1Method and device for correcting positional deviation of antenna in OAM multiplexed communication system
Publication Date: 2023.06.14 NIPPON TELEGRAPH & TELEPHONE CORP
  • EP3780428B1 patent drawingFigure 1
  • EP3780428B1 patent drawingFigure 2
  • EP3780428B1 patent drawingFigure 3

AI summary

An antenna displacement correction method for an OAM multiplexing communication system includes: a step of estimating a displacement amount by evaluating an evaluation function defined such that a theoretical channel response between a transmitting antenna and a receiving antenna matches a measured channel response estimated in a receiving station by using a known signal transmitted from a transmitting station, wherein the theoretical channel response has, as a parameter, the displacement amount indicating an amount of displacement of a reference axis predefined for each of the transmitting antenna and the receiving antenna from a predetermined position with respect to a desired relative positional relationship between the transmitting antenna and the receiving antenna; and a step of correcting a displacement of each of the transmitting antenna and the receiving antenna according to the estimated displacement amount.