A DFT-Based Scheme for PAPR Reduction in SR-OFDM Systems

This paper focuses on the peak-to-average power ratio (PAPR) reduction in symbol repetition-based orthogonal frequency division multiplexing (SR-OFDM) systems, and a discrete Fourier transform (DFT)-based scheme is proposed to reduce the PAPR of SR-OFDM signals. It is demonstrated that an SR-OFDM system exhibits a larger PAPR than a classical orthogonal frequency division multiplexing (OFDM) system because of the signal superposition of multiple branches, although the cyclic prefix (CP) overhead can be reduced in SR-OFDM systems. Besides, it is shown that the high PAPR is mainly because of the inverse DFT operation at the SR-OFDM transmitter. Therefore, a DFT-based scheme is proposed in this paper to compensate for the inverse DFT operation, without requiring side information or causing signal distortion. To verify the proposed scheme, a theoretical analysis is provided for the signal characteristics, and simulation results of the complementary cumulative distribution function are also given, together with the bit error ratio.