Stationarity of multiband channels for OTFS-based intelligent transportation systems

The development of communication systems for in-
telligent transportation systems (ITS) relies on their performance
in high-mobility scenarios. Such scenarios introduce rapid fluctu-
ations in wireless channel properties. As a promising solution for
vehicle-to-everything (V2X) communication, the orthogonal time
frequency space (OTFS) approach has emerged. Nevertheless,
the performance of OTFS systems is closely tied to time- and
frequency diversity of the wireless propagation channel. However,
there is a lack of understanding of the stationarity of the wireless
channels, especially in the millimeter wave (mmWave) frequency
bands. In this paper, we address this research gap by conducting
a comprehensive stationarity analysis of measured sub-6 GHz and
mmWave high-speed wireless channels. We evaluate the spatial
stationarity of a scenario, where the transmitter is moving at
high velocity. Furthermore, we investigate the influence of the
transmit antenna orientation on the channel spatial stationarity.
We could show that the spatial stationarity is proportional to the
wavelength.