OTFS Waveform with Phase Noise in sub-THz.

The availability of large bandwidths in the sub-THz bands appears to be a solution for increasing the capabilities of future wireless communication technologies. However, phase noise generated by oscillators in these bands generates significant signal distortion which needs to be addressed. In this paper, we study the impact of phase noise on OTFS. We propose phase noise compensation scheme and associated frame format. Two dedicated pilot schemes are studied for the phase noise tracking: the first one consists in adding pilots in the delay-Doppler (DD) domain while the other in the delay-Time (DT) domain. We highlight that compensating phase noise in DT domain gives better performance. A comparison between OFDM, DFT-s-OFDM and OTFS according to the 5G-NR numerology is presented. We show that the OTFS waveform is robust to phase noise and may even significantly outperform OFDM and DFT-s-OFDM.