Increasing the LED Bias Point of an OFDM-based VLC System through Multi-objective Optimization

The inherent nonlinearity introduced by light-emitting diodes (LEDs) in visible light communication challenges the parametrization of orthogonal frequency division multiplexing-based systems. A multi-objective optimization procedure, based on a non-dominated sorting genetic algorithm II, is presented to increases the LED bias and therefore, maximize the transmitted optical power and increases the spectral efficiency. Simulation results show that the signal-to-noise ratio (SNR) for a bit-error-rate of 1 × 10
⁻
3 decreases with the guard band due to intermodulation distortions. A guard-band of 1 % of the bandwidth is achieved with an SNR ≈ 14 and 18 dB, for 4-QAM and 16-QAM mappings, respectively. The SNR penalty for fixed optimized parameters, and varying the bias current, increases with the LED bias points that reach its non-linear region.