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Performance of dimming control scheme in visible light communication system
Zixiong Wang1, Wen-De Zhong, Changyuan Yu
1School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore.
Optics Express
|October 6, 2012
Summary
This study introduces a variable M-QAM OFDM system for visible light communication (VLC) to improve dimming control. The new system ensures high communication quality while reducing LED power consumption and simplifying implementation.
Area of Science:
- Optical Communications
- Wireless Networking
- Signal Processing
Background:
- Visible Light Communication (VLC) systems utilize LED lighting for data transmission.
- Pulse Width Modulation (PWM) is a common dimming control method in VLC.
- Standard PWM dimming can necessitate significantly higher data rates for On-Off-Keying (OOK) signals at low duty cycles, impacting performance.
Purpose of the Study:
- To develop an efficient dimming control scheme for VLC systems.
- To maintain communication quality (bit error rate < 10^-3) across varying LED brightness levels.
- To propose a power-saving and easily implementable VLC dimming solution.
Main Methods:
- Investigated the performance of a standard PWM dimming control scheme in VLC.
- Proposed a variable M-QAM Orthogonal Frequency Division Multiplexing (OFDM) VLC system.
- Adjusted the modulation order (M) based on the LED duty cycle to match brightness.
Main Results:
- The proposed variable M-QAM OFDM system achieved data rates not exceeding the original values across different duty cycles.
- Reduced LED lamp power was required to maintain communication quality.
- The system effectively balanced communication and illumination requirements.
Conclusions:
- The variable M-QAM OFDM VLC system offers a practical and power-efficient solution for dimming control.
- This approach simplifies the implementation of dimming control in VLC.
- It ensures reliable communication quality while optimizing energy usage.
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