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-to-Average-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 nonlinear distortion and significantly alleviate the distortion using CS compensation. The simulation and experiment results will verify the feasibility and advantages of the method.