On the degradation of OFDM-signals due to peak-clipping in optimally predistorted power amplifiers

The intermodulation noise in OFDM bandpass signals after passing an optimally predistorted power amplifier is investigated by a combination of analytical and numerical calculation. The results are illustrated for several modulation alphabets and it is shown that with ideal predistortion and a small symbol alphabet only a few dB of power back-off are required to achieve small error probabilities.