Visible Light Communication Duty Cycle Encoding
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Solution Overview
Problem
Current visible light communication methods that control brightness by using blank frames reduce system throughput and add complexity to the transmitter, especially when trying to maintain a 50% duty cycle, which worsens as the desired brightness level deviates from this value.
Innovation Solution
A method that selects a duty cycle based on the desired brightness level, encodes data using a corresponding code, and transmits it via visible light communication, allowing for decoding on the receiver side using a translation table, thereby controlling brightness without sacrificing data transmission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If blank frames are inserted to control brightness, then brightness control is achieved, but system throughput is reduced
Solution Approach 1:
The patent combines brightness control and data transmission into a single integrated process. Instead of using separate blank frames for brightness control and data frames for transmission, the invention encodes both brightness information and data within the same light emission patterns, allowing simultaneous achievement of both functions without sacrificing throughput.
Solution Approach 2:
The patent changes the duty cycle parameter of light emissions to control brightness while maintaining data transmission efficiency. By varying the duty cycle (the ratio of light-on time to total period) and encoding data within these duty cycle variations, the system achieves brightness control without requiring additional blank frames that would reduce throughput.
2Illumination intensity
If blank frames are used for brightness control, then brightness adjustment is possible, but transmitter complexity increases
Solution Approach 1:
The patent merges brightness control functionality with the existing data transmission encoder. The encoder simultaneously handles both data encoding and brightness control through duty cycle modulation, eliminating the need for separate brightness control circuits and reducing overall transmitter complexity.
Solution Approach 2:
The patent creates a universal encoding scheme that performs multiple functions: data transmission, brightness control, and synchronization. The duty cycle-based encoding system serves as both a data carrier and a brightness control mechanism, reducing the need for separate specialized components.
3Device complexity
If duty cycle is fixed at 50% for data transmission, then data encoding is simplified, but brightness control becomes difficult
Solution Approach 1:
The patent introduces duty cycle as a variable parameter instead of fixing it at 50%. By allowing the duty cycle to vary while maintaining the encoding structure, the system achieves both simplified encoding (through consistent pulse position modulation) and flexible brightness control (through adjustable duty cycle values).
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 data transmission while controlling light source brightness, reducing the need for additional power supplies and simplifying system upgrades by allowing control signals to be passed between light fixtures without rewiring, thus enhancing system throughput and reducing complexity.
Implementation Method 1
LED has the special characteristic of being able to turn the light on and off very fast. Data can then be transmitted by turning LEDs on and off at ultra high speed.
Data Source
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AI summary
In a first embodiment of the present invention, a method is provided comprising: receiving a selection of a desired brightness level of a light source; receiving a piece of data to be transmitted via visible light communication using the light source; selecting a duty cycle, described by an encoding scheme, based on the desired brightness level; encoding the data using the encoding scheme, wherein the encoding includes identifying a code corresponding to both the piece of data and the selected duty cycle; and transmitting the identified code via visible light communication using the light source.