Rotated DFT-Spread OFDM for Low-PAPR Transmissions

The rotated modulation (RM) is a promising standard solution for peak-to-average power ratio (PAPR) reduction in discrete Fourier transform spread orthogonal frequency-division multiplexing (DFT-s-OFDM) transmissions. This paper proposes a negligible-altered DFT-s-OFDM structure, termed Rotated DFT-s-OFDM, to intrinsically perform RM on all modulations in the present specification without changing the constellation mapper. The proposed scheme generalizes all possible phase rotation of RM by introducing a linear-scale-based rotation ratio to obtain the optimized phase rotation for maximum PAPR improvement. Simulation results demonstrate that our proposed structure with the optimized phase rotation can overall improve the PAPR performance for each modulation without any increase in computational complexity.