Screen-Based MIMO-OFDM Optical Wireless Communication
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Solution Overview
Problem
Current Optical Wireless Communication (OWC) technologies, such as IEEE 802.15.7, are limited by the need for dedicated communication apparatuses like VLC dongles and primarily use photo diodes, whereas international standardization is progressing towards using image sensors and broader wavelengths, including visible, infrared, and ultraviolet, necessitating a method for efficient optical wireless communication using screens and image sensors.
Innovation Solution
The method involves a modulator that receives transmission data and images, generates reference and data-embedded images, and transmits them through a light source panel, using techniques like OFDM, Hermitian symmetric matrices, cyclic prefixes, and pilot sequences to enable efficient optical wireless communication, allowing for the use of screens as light sources and image sensors as receivers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dedicated communication apparatuses like VLC dongles are used for optical wireless communication, then communication functionality is achieved, but device complexity and portability are worsened
Solution Approach 1:
The patent enables display devices to perform both display and communication functions simultaneously. The display screen modulates light to embed data while maintaining its primary display function, eliminating the need for dedicated communication apparatuses. Any device with a display screen and image sensor can communicate, making the system universal and multi-functional.
Solution Approach 2:
The display device itself serves as both transmitter and receiver. The screen modulates light to send data, while the image sensor captures light to receive data. This self-service capability eliminates dependency on external dedicated communication devices, reducing overall system complexity.
2Reliability
If photo diodes are used for optical wireless communication, then data transmission is achieved, but adaptability to different wavelengths and devices is limited
Solution Approach 1:
The patent uses image sensors instead of photo diodes, enabling compatibility with broader wavelength ranges including visible, infrared, and ultraviolet. Display devices with image sensors can communicate across multiple wavelength bands, significantly improving adaptability and versatility compared to photo diode-based systems.
3Adaptability or versatility
If screen light modulation is used for data transmission, then communication capability is achieved, but robustness against inter-pixel and inter-symbol interferences is reduced
Solution Approach 1:
The patent applies OFDM (Orthogonal Frequency Division Multiplexing) technology that segments data transmission across multiple orthogonal subcarriers. This segmentation approach divides the data stream into multiple parallel channels, each operating at a lower rate, which reduces inter-symbol interference and improves robustness against interference while maintaining communication capability.
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 enables efficient optical wireless communication using screens and image sensors, overcoming limitations of existing technologies by allowing data transmission through visible, infrared, and ultraviolet wavelengths, and improving robustness against inter-pixel and inter-symbol interferences.
Implementation Method 1
Light Emitting Diode (LED) lighting
Implementation Method 2
emits light in visible, infrared, and ultraviolet wavelengths
Implementation Method 3
using an image sensor such as a camera of a smart phone rather than a photo diode
Data Source
AI summary
An optical wireless transmission method according to an embodiment of the present invention comprises the steps of: a modulator receiving transmission data and a transmission image; the modulator generating a reference image on the basis of the transmission image; the modulator generating a data embedded image on the basis of the transmission data and the transmission image; and the transmitter sequentially transmitting the reference image and the data embedded image by means of a light source panel.