A nonlinear modelled low-complex ADO-OFDM for Visible light communication systems

In this paper, to quench the fifth-generation (5G) communication system's standards, we propose a new modulation technique called a nonlinear modelled low-complex asymmetrically clipped DC-biased optical-orthogonal frequency-division multiplexing (LADO-OFDM) for visible light communication (VLC) systems. The main idea of this scheme is to make use of the pre-distortion technique to mitigate the mutual interference between the even subcarriers correspond to DC biased optical-OFDM (DCO-OFDM) and asymmetrically clipped optical-OFDM (ACO-OFDM) at the transmitter section. Thus, the demodulation process can be done parallelly at the receiver, which results in decreased computing-complexity and latency when compared to asymmetrically clipped DC-biased optical-OFDM (ADO-OFDM). The performance of the proposed LADO-OFDM is studied under two generalized light-emitting diode (LED) models. The effect of nonlinear clipping distortion has been examined concerning the dynamic range and bias point of the LED. To improve the system performance, the LED dynamic range can be linearized by pre-distorting the transmitted signal and increasing the knee factor in the piecewise polynomial model and Rapps models respectively. The simulation results obtained by means of a Monte Carlo bit-error ratio (BER) simulations show that the BER performance of the proposed scheme is improved in comparison with the ADO-OFDM. Thus, the proposed scheme outperforms the ADO-OFDM in terms of BER, computing complexity, and latency.