Peak Reduction of Multi-Carrier Systems by Controlled Spectral Outgrowth

One of the major drawbacks with multi-carrier (MC) modulations is the large peak-to-average power ratio (PAPR) of the transmitted signal which significantly reduces the power amplifier efficiency and the system performance. Several PAPR reducing methods which do not decrease the system performance have been proposed. In this paper, we present a new low complexity PAPR reduction technique based on the controlled spectral outgrowth (CSO) of the nearby subcarriers which neither requires the transmission of additional information nor reduces the system performance and is independent of the mapping scheme. The proposed method can be easily combined with most of the methods in the literature to provide a further peak reduction in any MC or MC spread spectrum (MC-SS) system. An analog PAPR reduction about 2.5 dB at 10^-4 symbol clip probability and a power increase about 0.12 dB are obtained for a 256-subcarrier of OFDM transmission