Visible Light Communication Apparatus Using VPPM for Minute Dimming Control
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Solution Overview
Problem
Current visible light communication technologies face challenges in implementing minute dimming control, which is difficult to achieve and requires significant cost and time, and signal decoding becomes complicated when pulse width is adjusted finely.
Innovation Solution
A visible light communication method and apparatus that uses Variable Pulse Position Modulation (VPPM) to combine upper and lower dimming symbols, allowing for precise control of brightness by determining the number of symbols to be sent and generating a transmission sequence corresponding to a desired dimming level, enabling both data communication and minute dimming control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pulse width is adjusted minutely to achieve precise dimming control, then brightness control precision is improved, but signal decoding complexity increases and implementation cost and time increase
Solution Approach 1:
The patent segments the dimming control into two distinct phases: a coarse dimming phase using traditional PWM with standard pulse widths, and a fine dimming phase using VPPM with variable pulse positions. This segmentation allows the system to achieve precise brightness control without overcomplicating the entire signal decoding process, as only the fine dimming phase requires the more complex VPPM decoding when high precision is needed.
Solution Approach 2:
The patent introduces dynamic adaptability by allowing the pulse width to vary within a range rather than being fixed. The system can dynamically adjust the pulse width based on the required dimming precision level, using fixed pulse widths for coarse control and variable pulse widths for fine control. This dynamic approach enables precise dimming while maintaining decoding simplicity through conditional processing.
2Ease of manufacture
If traditional PWM is used for dimming control, then implementation is simple, but minute dimming control precision is insufficient
Solution Approach 1:
The patent divides the dimming control function into two segments: coarse dimming using simple PWM and fine dimming using VPPM. The coarse dimming phase maintains implementation simplicity by using standard PWM techniques, while the fine dimming phase adds precision only when necessary. This segmentation allows the system to achieve minute dimming control without requiring the entire system to be complex.
Solution Approach 2:
The patent merges PWM and VPPM techniques into a unified dimming control system. The system combines the simplicity of PWM with the precision of VPPM by processing dimming control in two stages: first using PWM for coarse adjustment, then using VPPM for fine adjustment. This merging enables both implementation simplicity and high precision to coexist in the overall system.
3Adaptability or versatility
If VPPM is used for both communication and dimming, then functional integration is achieved, but signal decoding becomes complicated
Solution Approach 1:
The patent segments the signal processing into distinct communication mode and dimming mode operations. When only communication is needed, standard PWM decoding is used. When dimming is required, the system switches to VPPM decoding. This segmentation allows functional integration of communication and dimming while managing decoding complexity through conditional processing based on operational mode.
Solution Approach 2:
The patent introduces dynamic mode switching to handle different operational requirements. The system dynamically adapts its decoding method based on whether communication, dimming, or both are required. This dynamic approach enables functional integration without permanently complicating the decoding process, as the complexity is activated only when needed.
Data Source
AI summary
Disclosed herein are a visible light communication method and apparatus. The visible light communication method includes determining a dimming level variable to perform minute dimming control, selecting an upper dimming symbol and a lower dimming symbol, which belong to Variable Pulse Position Modulation (VPPM) symbols, based on the dimming level variable, determining at least one of the number of upper dimming symbols to be sent and the number of lower dimming symbols to be sent based on the dimming level variable, and generating a transmission sequence corresponding to the dimming level variable by combining the upper dimming symbols and the lower dimming symbols based on the number of symbols to be sent.