Leveraging OTFS Modulation for High Doppler Shift Channel in Satellite Vehicular Networks

The 6G large-scale low earth orbit (LEO) satellite networks are expected to integrate with terrestrial networks to provide ubiquitous services for vehicular users. However, due to the mobility of both satellites and vehicles, satellite vehicular network (SVN) channels will be affected by the high Doppler effect and inter-carrier interference (ICI), which may lead to a decrease in the reliability of communications. Therefore, understanding the Doppler shift and leveraging appropriate symbol modulation techniques are key for SVNs to provide high quality communication services. In this paper, we introduce a realistic SVN channel based on the quasi-deterministic channel model that simulates the Doppler shift well compared to statistical models. Its channel properties are analyzed both in time-frequency and delay-Doppler (DD) domain, considering both line-of-sight (LOS) and non-line-of-sight (NLOS) conditions. Moreover, we leverage the orthogonal time frequency space (OTFS) modulation by mapping symbols into DD domain to adapt high Doppler shift channel. Extensive simulation results validate the advantage of OTFS compared with orthogonal frequency division multiplexing (OFDM) in SVN channel with high Doppler shift.