A Precoding-based PAPR Reduction Technique for UF-OFDM and Filtered-OFDM Modulations in 5G Systems

The universal filtered-orthogonal frequency division multiplexing (UF-OFDM) (also called universal filtered multicarrier (UFMC)) and the filtered-OFDM (F-OFDM) are candidates to be alternative to the OFDM modulation in the upcoming 5G systems thanks to their improved spectral occupation and resistance to the carrier frequency offset. However, like the majority of the multicarrier modulations, UF-OFDM and F-OFDM have a high peak-to-average power ratio (PAPR). This influences the operation mode of radio frequency components such as the power amplifier and the digital-to-analog converter. In this paper, a precoding-based PAPR reduction technique is proposed for both the UF-OFDM and the F-OFDM cases. A similar technique has been proposed in the literature for OFDM. The principle of this method is to transform the UF-OFDM signal to a lower order summation of single carrier signals and the F-OFDM signal to single carrier signal. The relevance of the proposed PAPR reduction technique is confirmed by simulation results. The latter show a PAPR reduction of at least 2.5 dB. Moreover, the proposed technique does not impact the bit error rate performance and lowers down the power spectral density tails at the power amplifier output.