Enhanced Non-Orthogonal Waveform (eNOW) for 5G Evolution and 6G

Abstract

Non-linearity of power amplifiers (PA) is the restriction of waveform design for 5G Evolution (5GE) and 6G in high frequency bands with large bandwidth. The low peak to average power ratio (PAPR) single carrier waveform discrete fourier transform spreading orthogonal frequency division multiplexing (DFT-s-OFDM) can be used as a candidate waveform for 5GE and 6G. To satisfy the extremely high data rate requirement in 6G, how to keep the low PAPR of single carrier waveform and improve its spectral efficiency (SE) will be the challenge. In our previous study, a novel non-orthogonal waveform (NOW) design was proposed by combining DFT-s-OFDM with FTN to improve SE with low PAPR. However, due to the spectrum extension caused by FTN, large out of band emission (OOBE) and signal-to-noise ratio (SNR) loss were observed. In this paper, we propose an enhanced non-orthogonal waveform (eNOW) to improve the SE of DFT-s-OFDM by designing the frequency domain power allocation to efficiently suppress OOBE and reduce SNR loss. Simulation results demonstrate that the OOBE and SNR loss of eNOW can be significantly reduced than that of NOW by design the frequency domain power allocation. With eNOW scheme, OOBE, PAPR and throughput gain can be achieved, simultaneously.