The OFDM (Orthogonal Frequency Division Multiplexing) allows a high bit rate with a robustness of transmission in multi-path fading channels. The main drawback is the very important amplitude fluctuation of its complex envelope which generates a high PAPR (Peak-to-Average Power Ratio). On the transmitter side, a high PAPR moves the working point of the power amplifier (PA) far from its saturation region so that the input signal is not well saturated. Consequently, PA power efficiency decreases with an increase of its power consumption. In the context of mobility, the energy resources are limited and the employment of multi-carrier modulations needs a signal processing in order to reduce the PA power consumption. The purpose of this work is the optimization of the PA power consumption without degradation of the received signal quality. The PAPR reduction method named clipping and filtering has been improved generating a new technique called invertible clipping. This system comprises: the soft clipping for the PAPR reduction, the filtering for an acceptable ACPR (Adjacent Channel Power Ratio) value, and the inversion to compensate the distortions due to the clipping. In presence of an AWGN (Additive White Gaussian Noise) channel, the invertible clipping system allows to obtain a gain on the PA back-off and, consequently, an improvement of its power efficiency. The invertible clipping reduces the PA power consumption of 11% maintaining the same BER (Bit Error Rate) performance. Moreover, in-depth analysis of the ACPR has been realized and a new parameter has been introduced (N_ACPR) which allows a better evaluation of spectral regrowth on the output spectrum.
