Out of Band Analysis in various 5G-NR Downlink Waveforms with Different Numerologies

The standardization of the first phase 5G system in Release 15 named New Radio (NR) will soon move on to the stand-alone version with intention to bring it commercially to the market around 2020. This paper investigates the impact of power amplifier in OFDM-based waveforms including CP-OFDM, F-OFDM and W-OFDM. We first derive a mathematical model for these OFDM-based waveforms. Then we analyze the impact of power amplifier (PA) to the out-of-band (OOB) waveform, which is a critical component in the densely spectrum with different channel widths using scalable numerologies. It is shown that W-OFDM and F-OFDM are more suitable than the conventional CP-OFDM. The provided results of this paper thus facilitate knowledge of design and practice for further NR features. As the simulation results, without PA clipping, the W-OFDM and F-OFDM present better OOB characteristic than CP-OFDM, while applying PA clipping both of them show the similar performance. Additionally, another W-OFDM design with PA clipping shows advantages to implement for 5G NR waveform.