Low-Complexity and Robust PAPR Reduction and LED Nonlinearity Mitigation for UACO-OFDM LiFi Systems

We propose a low-complexity and highperformance joint peak-to-average power ratio (PAPR) reduction and light emitting diode (LED) nonlinearity mitigation approach for unipolar asymmetrically clipped optical-orthogonal frequency division multiplexing (UACO-OFDM) based light fidelity (LiFi) systems. This is the first reported work to apply nonlinear compression based on μ-law companding for UACO-OFDM LiFi systems to reduce PAPR. In order to avoid the effect of the nonlinearity of LED, the transmitted signals are compressed further linearly. The signal distortion caused by nonlinear and linear compression is compensated for using multiple LEDs for simultaneous transmission. The proposed joint PAPR reduction and LED nonlinearity mitigation approach provides low complexity, searching is not required. Also, it is spectrum- and energy-efficient, requiring no pilot and consuming no extra transmission power. Simulation results show that the proposed approach significantly outperforms the state-of-the-art methods in terms of complementary cumulative distribution function (CCDF) and bit error rate (BER), and that it is more robust against the LED nonlinearity than conventional UACO-OFDM LiFi systems and other methods in the literature.