Visible Light Signal Generation Using Luminance Modulation
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Solution Overview
Problem
Conventional visible light communication methods are limited to devices with three color light sources and struggle to enable communication between various devices, including those without lighting functions, due to insufficient computational performance or cost constraints.
Innovation Solution
A visible light signal generating method that uses alternating luminance values to create a preamble and payload, allowing for communication by modulating the brightness of a light source, enabling devices without three color light sources to participate in data transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional visible light communication methods using three color light sources are used, then communication can be established between devices with lighting functions, but devices without three color light sources (including those with insufficient computational performance or cost constraints) cannot participate in communication
Solution Approach 1:
The patent applies universality by enabling visible light communication using a single white light source instead of requiring three color light sources. The system can function with simple lighting devices that lack complex multi-color configurations, making the communication technology accessible to a broader range of devices including those with cost or performance constraints.
Solution Approach 2:
The patent changes the parameter basis for communication from color differentiation (requiring three color light sources) to luminance variation (using a single white light source). By modulating the luminance of a white light source according to encoding schemes, the system achieves communication without requiring complex multi-color hardware configurations.
2Adaptability or versatility
If simple white light sources are used for communication, then device compatibility improves, but signal encoding and decoding complexity increases due to need for computational processing
Solution Approach 1:
The patent segments the communication signal into distinct components: preamble sequences for synchronization and payload data for information transmission. The encoding uses structured patterns (alternating high/low luminance sequences) that can be efficiently processed. This segmentation allows receivers to process information in manageable stages, reducing overall computational burden.
Solution Approach 2:
The patent employs periodic luminance variations in the form of alternating high and low luminance sequences for encoding data. This periodic structure creates predictable patterns that simplify detection and decoding at the receiver end, as the system can anticipate the rhythmic nature of the signal and process it more efficiently compared to irregular variations.
3Adaptability or versatility
If luminance modulation is used for data transmission, then communication between various devices is enabled, but communication reliability may be affected by ambient light interference
Solution Approach 1:
The patent uses excessive luminance modulation by varying the light source intensity between distinctly high and low levels rather than using subtle variations. This excessive action creates a larger signal-to-noise ratio, making the transmitted signal more distinguishable from ambient light interference and improving detection reliability despite the presence of environmental light conditions.
Solution Approach 2:
The patent incorporates feedback mechanisms through acknowledgment packets and error detection codes in the communication protocol. The receiver sends feedback to the transmitter about successful reception or detected errors, allowing for retransmission if necessary. This feedback loop ensures reliable communication even when ambient light interference causes occasional signal degradation.
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 method enhances communication efficiency and reliability, enabling data transmission between a wide range of devices, including those without traditional lighting functions, by effectively using luminance changes to convey data.
Implementation Method 1
a visible light signal generating method for generating a visible light signal transmitted in response to a change in a luminance of a light source
Data Source
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AI summary
A visible light signal generating method is a method for generating a visible light signal transmitted in response to a change in a luminance of a light source of a transmitter, and includes: generating a header (SHR), where the header is data in which first and second luminance values, which are different luminance values, alternately appear along a time axis; generating a PHY payload A and a PHY payload B by determining a time length according to a first mode, where the time length is a time length during which each of the first and second luminance values continues in the data in which the first and second luminance values alternately appear along the time axis, and the first mode matches a transmission target signal; and generating the visible light signal by joining the header (SHR), the PHY payload A and the PHY payload B.