Low-PAPR OFDM-based waveform for fifth-generation cellular communications

We introduce a novel technique for improving PA efficiency and coverage of communication links, especially advantageous for the uplink at high frequencies (cm/mm-Waves). The technique is based on a superposition of several DFT-s-OFDM (a.k.a. SC-FDM) signals, whose modulated symbol sequences and pulse shaping functions are coupled in a specially crafted manner. The resulting low-PAPR waveforms enable transmission with essentially no output power back-off (OBO), complying with rigid spectral requirements even when using PAs with highly non-linear behavior, expected from 5G cost-effective RF solutions. A relatively simple modification of a plain DFT-s-OFDM transmitter is required to support these waveforms. The inherent controlled ISI admits low-complexity BCJR-type demodulation, yet detection losses are small relative to the transmit power gains, thus yielding large net gains in link budget compared to competing transmission schemes.