Are side-band tones beneficial for PAPR reduction in FBMC?

The Filter Bank Multicarrier (FBMC) modulation scheme has recently gained a lot of research interest due to its characteristics in time and frequency spanning. However, as Orthogonal Frequency Division Multiplexing (OFDM), it suffers from high Peak to Average Power Ratio (PAPR) leading to in-band and out-of-band distortion induced by the non-linearities of the power amplifier. In OFDM, the problem of PAPR reduction has been widely investigated. However, the different techniques seen in OFDM could not be directly applied in FBMC due to the polyphase network filters utilized therein. In this paper, we propose to use the null-subcarriers of the side-bands to reduce the PAPR value. Indeed, due to the low side-band power level of the FBMC, these sub-carriers could be modulated with an acceptable value to accommodate the PAPR reduction. The proposed method is designed through a geometric method aiming at minimizing the power of the side-band while minimizing the PAPR value. Compared with the traditional Tone Reservation (TR) technique, we show that the proposed technique presents good results in terms of PAPR Complementary Cumulative Distributed Function (CCDF) and Magnitude Error Rate (MER) and with a low power increase.