The statistical correlation between clipping noise and PAPR in OFDM systems

In recent years, the PAPR (peak-to-average power rate) of OFDM system has been intensively investigated and the published works mainly focus on how to reduce PAPR since high PAPR will leads to clipping of the signal when passed through a nonlinear amplifier. In this paper we investigate the statistical correlation between PAPR and the clipping noise. An interesting result is that the power of clipping noise is not always highly correlated with PAPR, especially when the signal is heavily or slightly clipped. Moreover, for the fixed transmit power and clipping threshold (i.e. the same amplifier with the same backoff), the average power of clipping noise is independent of the number of subcarriers in OFDM and the noise power is more stable, thus the OFDM systems with larger number of subcarrier even have better performance. Whereas we know that larger subcarrier number will always make the PAPR worse.