LED communications with linear complexity compensation of dynamic nonlinear distortion
Applied Optics
|January 6, 2023
Summary
This study simplifies light emitting diode (LED) nonlinearity using a new model. Nonlinear pre- and postdistortion techniques are derived, offering improved performance over linear equalizers for LED communications.
Area of Science:
- Electrical Engineering
- Optical Communications
- Signal Processing
Background:
- Light emitting diodes (LEDs) introduce dynamic nonlinear distortion when used in communications.
- Understanding the second-order Volterra kernel is crucial for mitigating this distortion.
Purpose of the Study:
- To develop a simplified model for LED nonlinearity.
- To derive nonlinear pre- and postdistorter structures for distortion compensation.
- To evaluate the performance of these techniques against linear equalizers.
Main Methods:
- Frequency-domain factorization of the second-order Volterra kernel.
- Derivation of time-domain model (two linear filtrations and squaring).
- Application of pth inverse theory for pre- and postdistorter design.
Main Results:
- A simplified, computationally linear time-domain model for LED nonlinearity.
- Effective nonlinear pre- and postdistorters with linear complexity.
- Comparable performance between pre- and postdistortion, outperforming linear equalizers.
- Predistortion may increase peak-to-average power ratio, favoring postdistortion in some cases.
Conclusions:
- The simplified LED model accurately represents nonlinearity.
- Nonlinear pre- and postdistortion are effective and efficient methods for mitigating LED distortion.
- The simplified equalizer shows performance similar to quadratic Volterra equalizers.
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