Localized SC-FDMA with constant envelope

Singe-carrier frequency-division multiple access (SC-FDMA) enables simplified equalization and flexible multiuser scheduling in the frequency domain. Compared to orthogonal frequency division multiple access (OFDMA), it has reduced envelope fluctuations in the same bandwidth. SC-FDMA is widely used in mobile communications, where the focus is on spectral efficiency. Here, we consider an evolution towards better energy efficiency. We propose evolved transmission schemes combining energy-efficient modulation and frequency-domain filtering. Using Gaussian minimum-shift keying (GMSK) and filtered π/2 binary phase-shift keying (BPSK), the peak-to-average power ratio (PAPR) can be reduced down to 0 and 1.9 dB, respectively, while penalties at the receiver side are negligible.