Multi-stage Amplitude Modulation for Visible Light Communication
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Solution Overview
Problem
Conventional visible light communication methods using LEDs face low transmission rates due to flashing delay issues, which complicate synchronization and lead to bit reception errors.
Innovation Solution
Implementing a multi-stage amplitude modulation-based method that divides information into multiple bits represented by at least three levels, where transitions between levels indicate information units, eliminating the need for synchronization and improving information density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional binary flashing method is used, then simplicity of implementation is maintained, but transmission rate is low due to flashing delay
Solution Approach 1:
The patent segments information into multiple bits per signal unit (e.g., 2 bits per unit with four levels). This segmentation allows parallel transmission of multiple bits simultaneously, increasing transmission rate without proportionally increasing system complexity
Solution Approach 2:
The patent transitions from binary (2-level) to multi-level amplitude modulation (at least three levels, preferably four levels). By adding an amplitude dimension to the signaling scheme, multiple bits can be encoded in each signal unit, dramatically improving transmission rate while maintaining LED hardware simplicity
2Loss of information
If multi-level amplitude modulation is implemented, then information density is improved, but synchronization complexity increases due to flashing delay
Solution Approach 1:
The patent employs self-synchronizing mechanisms where the receiver automatically adapts to the transmitter's timing by detecting signal patterns and adjusting its sampling clock. This eliminates the need for complex external synchronization signals, allowing multi-level modulation to achieve high information density without proportional increases in synchronization complexity
Solution Approach 2:
The patent incorporates preliminary synchronization training sequences before actual data transmission. These training sequences allow the receiver to pre-adjust its timing and amplitude reference levels, ensuring accurate detection of subsequent multi-level signal units without requiring complex real-time synchronization
3Speed
If conventional binary coding is used, then ease of decoding is maintained, but transmission speed is limited by LED switching delay
Solution Approach 1:
The patent changes the amplitude parameter of the LED signal from binary (2 levels) to multi-level (at least three levels, preferably four levels). This parameter change allows encoding of multiple bits per signal unit, increasing transmission speed. The decoding difficulty is managed through threshold-based detection and error correction codes, maintaining practical implementability
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
Enhances transmission rates by using level transitions to represent information, reducing errors and improving user experience through efficient data grouping and modulation.
Implementation Method 1
a technology for using an LED (light emitting diode) of an electronic device to transmit a visible light signal
Implementation Method 2
Information may be obtained after a high-speed light signal that includes digital information undergoes photoelectric conversion
Data Source
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AI summary
The present application relates to multi-stage amplitude modulation-based methods, apparatuses, and systems for coding and decoding a visible light signal. The coding method includes the following steps: dividing to-be-transmitted information into multiple information units, where each information unit includes multiple bits; converting the multiple information units into multiple electrical signal units indicated by at least three levels, where an interval indicated by a first level in the at least three levels exists between adjacent electrical signal units, and each electrical signal unit uses a combination of other levels in the at least three levels to represent the multiple bits of a corresponding information unit; combining the electrical signal units to obtain a coded electrical signal; and transmitting the coded electrical signal in a visible light signal form.