Color-Space Symbol Mapping for Faster, Stable Optical Transmission

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Solution Overview

Problem

Existing visible light communication systems face challenges in improving reception quality and transmission speeds, particularly when using light sources that need to maintain a consistent brightness to avoid perceptible flickering.

Innovation Solution

A transmission device modulates optical signals using a two- or three-dimensional color space, and a reception device demodulates these signals symbol-by-symbol, utilizing a plurality of light receiving elements and demapping techniques in the same color space.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If light intensity is modulated for data transmission, then transmission speed is improved, but reception quality deteriorates due to perceptible flickering

Engineering Contradiction:
Improvetransmission speedVSAvoidreception quality
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent transitions from one-dimensional intensity modulation to two-dimensional color space modulation. By mapping modulation symbols to signal points in a color space with multiple dimensions (e.g., CIE xyY, CIE LUV, or RGB), the system can encode more information per symbol while maintaining more stable light output, thereby improving both transmission speed and reception quality simultaneously

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

2Productivity

If conventional intensity modulation is used, then implementation is simple, but transmission speed is limited

Engineering Contradiction:
Improvetransmission speedVSAvoidmodulation complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent changes the modulation parameter from single intensity dimension to multi-dimensional color space parameters. By utilizing multiple color components (e.g., R, G, B or x, y, Y) instead of only intensity, the system achieves higher transmission speeds through increased symbol capacity while the complexity is managed through systematic mapping and demapping processes

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 enhances reception quality and transmission speeds in visible light communication by effectively utilizing the characteristics of CMOS sensors and optimizing modulation and demodulation processes.

Implementation Method 1

a light receiver generates a reception signal by receiving an optical signal via a plurality of light receiving elements

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentEP3618310B1Transmission device, transmission method, reception device, and reception method
Publication Date: 2025.09.03 PANASONIC INTELLECTUAL PROPERTY CORP OF AMERICA
  • EP3618310B1 patent drawingFigure 1
  • EP3618310B1 patent drawingFigure 2
  • EP3618310B1 patent drawingFigure 3

AI summary

A transmission device (100) includes a symbol generator (102) that generates a modulation symbol by mapping transmission data to a signal point arranged in a two-dimensional or three-dimensional color space; and an outputter (104) that outputs an optical signal modulated according to the modulation symbol.