The Clipping and Nonlinear Distortion Compensation For Underwater Acoustic OFDM System

Orthogonal frequency division multiplexing (OFDM) is a promising alternative modulation for underwater acoustic communication due to its ability in mitigating multipath effects. However, the high peak-to-average ratio (PAPR) constraints the power value level especially for long distance transmission. The problem of non-linear distortion generated by using one or more non-linear devices cannot be ignored when the OFDM signal is used to transmit. A novel clipping system model is proposed to simulate the effect of the non-linear distortion, which exploits the clipping operation to reduce the Peak-toAverage-Power-Ratio (PAPR). A new method based on compressed sensing (CS) is used to estimate the clipping values and compensate the effect of the non-linear distortion. It is shown that the clipping and compensation scheme can simulate the non-linear distortion and significantly alleviate the distortion using CS compensation. The simulation and experiment results will verify the feasibility and advantages of the method.