Power efficiency comparison of OFDM and single-carrier signals

The power efficiency of the linear modulation signals in terms of the required output back-off of the power amplifier is analyzed and compared, based on a simple approach that deals only with the knowledge of the statistical distribution of the instantaneous power of the input signals. The proposed method may also be useful for predicting the efficiency of the peak-to-average power reduction techniques for single-carrier and OFDM signals for a given level of the adjacent channel power ratio. As widely recognized, the result shows that the efficiency of the OFDM signal is considerably poor without peak power reduction. Thus the improvement of the power efficiency by simple clipping and filtering is also studied.