Adaptive Peak-to-Average Power Reduction Architecture for Multicarrier Signals with Mixed Modulations

One of the major drawbacks of multicarrier transmission is the high peak-to-average power ratio (PAPR) of the transmit signal. In this paper, we propose a PAPR reduction technique for mixed-modulation multicarrier transmission into subcarriers. We show that the knowledge of the allocation of modulation schemes among the subcarriers gives an extra degree of freedom compared with traditional approaches, and results in the simultaneous enhancement of the PAPR reduction level and achievement of the required error vector magnitude (EVM) performances. We demonstrate that PAPR in the transmitting signal is significantly reduced when the EVM distortion for each modulation schema is allowed to increase up to its upper specification limit. We also show that the PAPR regrowth is prevented when the spectrum shaping filter´s passband is allowed to increase.