Related Experiment Video
Updated: Apr 15, 2026

09:36
Characterization of Anisotropic Leaky Mode Modulators for Holovideo
Published on: March 19, 2016
8.4K
Hybrid time-frequency domain equalization for LED nonlinearity mitigation in OFDM-based VLC systems
Optics Express
|April 4, 2015
Summary
A new hybrid equalization method effectively reduces white light emitting diode (LED) nonlinearity in visible light communication (VLC) systems. This approach significantly enhances modulation index and bit error rate performance.
Area of Science:
- Optical Communications
- Signal Processing
Background:
- Visible Light Communication (VLC) systems utilize white light emitting diodes (LEDs) for data transmission.
- LEDs exhibit nonlinear distortions that degrade signal quality in OFDM-based VLC systems.
Purpose of the Study:
- To propose and experimentally validate a novel hybrid time-frequency domain equalization scheme.
- To mitigate nonlinear distortions introduced by LEDs in OFDM-VLC systems.
Main Methods:
- A hybrid equalization scheme separating linear and nonlinear distortion compensation.
- Frequency domain equalization for linear distortion.
- Adaptive nonlinear time domain equalization (N-TDE) for nonlinear distortion.
Main Results:
- The proposed N-TDE efficiently mitigates LED nonlinearity with a small number of parameters.
- Significant enhancement in modulation index (MI) and bit error rate (BER) performance was observed.
- Experimental demonstration validates the effectiveness of the hybrid scheme.
Conclusions:
- The hybrid time-frequency domain equalization scheme effectively addresses LED nonlinearity in OFDM-VLC.
- The N-TDE offers a robust solution for improving the performance of VLC systems.
Related Concept Videos
Linear Approximation in Frequency Domain
454
Linear systems are characterized by two main properties: superposition and homogeneity. Superposition allows the response to multiple inputs to be the sum of the responses to each individual input. Homogeneity ensures that scaling an input by a scalar results in the response being scaled by the same scalar.
In contrast, nonlinear systems do not inherently possess these properties. However, for small deviations around an operating point, a nonlinear system can often be approximated as linear....
In contrast, nonlinear systems do not inherently possess these properties. However, for small deviations around an operating point, a nonlinear system can often be approximated as linear....
454
Time and frequency -Domain Interpretation of Phase-lead Control
535
Phase-lead controllers are commonly used in various control systems to enhance response speed and stability. Adjusting the brightness on a television screen offers a practical example of phase-lead control. When contrast is enhanced, a phase-lead controller is employed. Mathematically, phase-lead control is identified when the first parameter is smaller than the second.
The design of phase-lead control involves the strategic placement of poles and zeros to balance steady-state error and system...
The design of phase-lead control involves the strategic placement of poles and zeros to balance steady-state error and system...
535
Linear Approximation in Time Domain
426
Nonlinear systems often require sophisticated approaches for accurate modeling and analysis, with state-space representation being particularly effective. This method is especially useful for systems where variables and parameters vary with time or operating conditions, such as in a simple pendulum or a translational mechanical system with nonlinear springs.
For a simple pendulum with a mass evenly distributed along its length and the center of mass located at half the pendulum's length,...
For a simple pendulum with a mass evenly distributed along its length and the center of mass located at half the pendulum's length,...
426
Time and frequency -Domain Interpretation of Phase-lag Control
453
Phase-lag controllers are widely used in control systems to improve stability and reduce steady-state errors. A dimmer switch controlling the brightness of a light bulb serves as a practical example of phase-lag control, gradually adjusting the bulb's brightness. Mathematically, phase-lag control or low-pass filtering is represented when the factor 'a' is less than 1.
Phase-lag controllers do not place a pole at zero, but instead influence the steady-state error by amplifying any...
Phase-lag controllers do not place a pole at zero, but instead influence the steady-state error by amplifying any...
453
Linear time-invariant Systems
1.1K
A system is linear if it displays the characteristics of homogeneity and additivity, together termed the superposition property. This principle is fundamental in all linear systems. Linear time-invariant (LTI) systems include systems with linear elements and constant parameters.
The input-output behavior of an LTI system can be fully defined by its response to an impulsive excitation at its input. Once this impulse response is known, the system's reaction to any other input can be...
The input-output behavior of an LTI system can be fully defined by its response to an impulsive excitation at its input. Once this impulse response is known, the system's reaction to any other input can be...
1.1K
Properties of Fourier Transform II
945
The Fourier Transform (FT) is an essential mathematical tool in signal processing, transforming a time-domain signal into its frequency-domain representation. This transformation elucidates the relationship between time and frequency domains through several properties, each revealing unique aspects of signal behavior.
The Frequency Shifting property of Fourier Transforms highlights that a shift in the frequency domain corresponds to a phase shift in the time domain. Mathematically, if x(t) has...
The Frequency Shifting property of Fourier Transforms highlights that a shift in the frequency domain corresponds to a phase shift in the time domain. Mathematically, if x(t) has...
945

