A Novel Partitioning Scheme for Partial Transmit Sequence Method

An efficient and distortionless partitioning scheme for the Partial Transmit Sequence (PTS) method is proposed to control the nonlinear property producing other peaks in the Orthogonal Frequency Division Multiplexing (OFDM) transmit signal. The approach is flexible and works with a limited and controlled number of subcarriers and can significantly improve peak power statistics of the optimized transmit signal. The traditional partitioning strategy of the PTS method allows all subchannels/subcarriers to contribute in the reduction of the peak-to-average power ratio (PAPR). Therefore, the traditional scheme is ineffective for controlling the nonlinear property, which may produce other peaks by rotating all subchannels of the OFDM signal. Although the PTS method can optimize the value of PAPR, the effect of the nonlinear property of the PTS method has not been properly addressed in the literature. In this paper, we examine the number of actual parameters/rotations used in the PTS method by suitably testing the nonlinear property on the rotated partial sequences. In contrast to the traditional partitioning strategy, the proposed strategy involves rotating half of the separated subcarriers to eliminate the effect of producing other peaks. The traditional and proposed schemes are compared through simulation results with respect to the required system complexity and the minimum PAPR of the OFDM transmit signal. Finally, it is shown that the controlled partitioning scheme is closer to the theoretical limit of PAPR optimization, and it also requires less system complexity than the traditional scheme.