LED nonlinearity mitigation in LACO-OFDM optical communications based on adaptive predistortion and postdistortion...

Area of Science:

• Optical Communications
• Signal Processing

Background:

• White light emitting diodes (WLEDs) are cost-effective optical sources for visible light communications (VLC).
• LED nonlinear distortion significantly degrades VLC system performance.

Purpose of the Study:

• To investigate and compare three compensation techniques for mitigating LED nonlinearity in VLC systems.
• To evaluate the effectiveness of predistortion and postdistortion methods on layered asymmetrically clipped optical orthogonal frequency division multiplexing (ACO-OFDM).

Main Methods:

• Employed polynomial-based predistorters and postdistorters.
• Utilized a look-up-table-based predistorter.
• Analyzed performance using error vector magnitude (EVM) and bit error rate (BER) in an additive white Gaussian noise (AWGN) channel.

Main Results:

• Polynomial-based predistorters and postdistorters compensated for LED nonlinearity with an additional signal-to-noise ratio (SNR) of 0.25 dB at a BER of 10^-3.
• The look-up-table-based predistorter achieved the same BER with a lower SNR penalty compared to polynomial methods.

Conclusions:

• Predistortion and postdistortion techniques are effective in overcoming LED nonlinear behavior in VLC systems.
• Look-up-table-based predistorters offer superior SNR efficiency for mitigating LED nonlinearity in ACO-OFDM based VLC.