A Novel Constellation Reshaping Method for PAPR Reduction of OFDM Signals

Abstract

In this paper, we propose a constellation reshaping method for peak-to-average power ratio (PAPR) reduction in orthogonal frequency division multiplexing (OFDM) systems. The key idea of the proposed method is to generate a reshaped quadrature amplitude modulation (R-QAM) constellation, in which the minimum distance of the R-QAM is the same as that of the traditional QAM constellation. When the novel R-QAM constellation is employed with the traditional partial transmit sequence (PTS) and selected mapping (SLM) methods in OFDM systems, called as the R-PTS and R-SLM methods in this paper, respectively, the mean square errors between the constellations of the received data and each R-QAM rotated by different phase rotation factors are calculated at the receiver, and the phase rotation factor with the minimum mean square error is selected to recover the original data without side information. Therefore, the flexibility in phase rotation choice and the ability to avoid data rate loss make the R-PTS and R-SLM methods more suitable for good bit-error-rate performance in OFDM systems. Theoretical analysis and simulation results show that the R-PTS and R-SLM methods could provide the same PAPR reduction and bit-error-rate as those of the conventional PTS and SLM methods with perfect side information, respectively.