A New Subblock Segmentation Scheme in Partial Transmit Sequence for Reducing PAPR Value in OFDM Systems

Partial transmit sequence (PTS) is considered an efficient algorithm to alleviate the high peak-to-average power ratio (PAPR) in orthogonal frequency division multiplexing (OFDM) systems. The PTS technique is depended on the partitioning the input data sequence into the several subblocks, and then weighting these subblocks with a group of the phase factors. There are three common types of partitioning schemes: interleaving scheme (IL-PTS), adjacent scheme (Ad-PTS), and pseudo-random scheme (PR-PTS). The three conventional partitioning schemes have various performances of the PAPR value and the computational complexity pattern which are considered the main problems of the OFDM system. In this paper, the three ordinary partition schemes are analyzed and discussed depending on the capability of reducing the PAPR value and the computational complexity. Furthermore, new partitioning scheme is introduced in order to improve the PAPR reduction performance. The simulation results indicated that the PR-PTS scheme could achieve the superiority in PAPR mitigation compared with the rest of the schemes at the expense of increasing the computational complexity. Furthermore, the new segmentation scheme improved the PAPR reduction performance better than that the Ad-PTS and IL-PTS schemes

Low-complexity PTS schemes using OFDM signal rotation and pre-exclusion of phase rotating vectors

Partial transmit sequence (PTS), a well-known peak-to-average power ratio (PAPR) reduction scheme for orthogonal frequency division multiplexing (OFDM) systems, has been actively investigated to reduce its high computational complexity. Ku et al. proposed a selection method of dominant time-domain samples and by only using the selected samples, the PAPR of each alternative OFDM signal vector is calculated. This method clearly reduces the computational complexity but it is crucial to select proper time-domain samples to achieve acceptable PAPR reduction performance. In this study, a new selection method of dominant time-domain samples is proposed based on rotating samples of inverse fast Fourier transformed (IFFTed) subblocks to the local area on which the corresponding sample of the IFFTed first subblock is located. Moreover, pre-exclusion of phase rotating vectors based on the above time-domain sample rotation is proposed to further reduce the computational complexity. Numerical results confirm that the proposed PTS schemes substantially reduce the computational complexity with negligible degradation of PAPR reduction performance