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Exploring the effect of LED nonlinearity on the performance of layered ACO-OFDM
Applied Optics
|September 9, 2020
Summary
This study analyzes how light-emitting diode (LED) nonlinearity impacts Layered Asymmetrically Clipped Optical Orthogonal Frequency Division Multiplexing (LACO-OFDM) for visible light communication (VLC). Results show nonlinearity significantly degrades system performance, especially with higher-order distortions.
Area of Science:
- Optical Communications
- Wireless Technology
- Signal Processing
Background:
- Visible Light Communication (VLC) utilizes Light Emitting Diodes (LEDs) for data transmission, offering high efficiency and low cost.
- LEDs introduce nonlinear effects that degrade signal quality and limit performance in VLC systems, particularly for multicarrier modulation.
- Existing systems like Asymmetrically Clipped Optical Orthogonal Frequency Division Multiplexing (ACO-OFDM) are susceptible to these nonlinearities.
Purpose of the Study:
- To investigate the impact of LED nonlinearity on the performance of Layered Asymmetrically Clipped Optical Orthogonal Frequency Division Multiplexing (LACO-OFDM).
- To analyze the combined effects of second-order nonlinear distortion and clipping noise under varying nonlinearity strengths and power levels.
- To evaluate the performance of LACO-OFDM with a nonlinear LED model across different numbers of layers and compare it with ACO-OFDM.
Main Methods:
- Mathematical modeling of LED nonlinearity, including second-order distortion.
- Analysis of clipping noise in conjunction with nonlinear distortion.
- System performance evaluation of LACO-OFDM with a variable number of layers using a nonlinear LED model.
- Comparative analysis with ACO-OFDM under identical nonlinear conditions.
Main Results:
- LED nonlinearity significantly degrades the performance of LACO-OFDM systems.
- The combined effect of second-order nonlinear distortion and clipping noise is substantial, varying with nonlinearity strength and signal power.
- Performance degradation is observed across different numbers of layers in LACO-OFDM, with ACO-OFDM (the first layer) showing comparable sensitivity to nonlinearity.
Conclusions:
- LED nonlinearity is a critical limiting factor for high-performance VLC systems employing LACO-OFDM.
- Mitigation strategies for LED nonlinearity are essential for realizing the full potential of LACO-OFDM in visible light communication.
- The findings highlight the need to account for nonlinear LED behavior in the design and optimization of future VLC systems.
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