Clipping distortion analysis and optimal power allocation for ACO-OFDM based visible light communication

This paper analyses the nonlinear clipping distortion of asymmetrically clipped optical OFDM (ACO-OFDM) based visible light communications system (VLC) and proposes an optimal power allocation method for reducing the clipping distortion. Firstly, we analyze the LED nonlinear clipping distortion based on the clipping process model that original signal directly added nonlinear clipping distortion components. Then, the effective signal to noise ratio (ESNR) is defined to measure the clipping distortion, and the clipping distortion analysis is converted into ESNR analysis. Finally, the optimal power allocation under optical power constraints base on the principle of ESNR optimum is proposed. Simulation results show that reasonable power allocation can effectively reduce the LED nonlinear clipping distortion and ensure that the bit error rate (BER) is less than 10^-3.