Channel Sounding and Ray Tracing for Intrawagon Scenario at mmWave and Sub-mmWave Bands

In order to realize the vision of smart rail mobility, a seamless high-data rate wireless connectivity with up to dozens of gigahertz bandwidth will be required. This forms a strong motivation for exploring the underutilized millimeter wave (mmWave) and sub-mmWave bands. In this article, the wireless channel in one smart rail mobility scenario-the intrawagon scenario-is characterized through ultrawideband (UWB) channel sounding and ray tracing (RT) at mmWave and sub-mmWave bands. To begin with, a series of horizontal directional scan-sounding measurements are performed inside a real high-speed train wagon at 60 and 300 GHz frequency bands with a bandwidth of 8 GHz. Correspondingly, the channel characteristics such as Rician K-factor, root-mean-square (rms) delay spread (DS), azimuth spread of arrival, and azimuth spread of departure are extracted and analyzed. Based on the measurements, a self-developed RT simulator is validated through the reconstruction of the three-dimensional wagon model and the calibration of the electromagnetic (EM) properties of the main materials. This gives the chance to physically interpret the measurement results and characterize the intrawagon mmWave and sub-mmWave channels more comprehensively through extensive RT simulations.

Automated summary

To achieve the vision of smart rail mobility, high-data rate wireless connectivity with up to dozens of gigahertz bandwidth is required, which drives the exploration of underutilized millimeter wave (mmWave) and sub-mmWave bands. In this study, the wireless channel within a smart rail mobility scenario is characterized through ultrawideband (UWB) channel sounding and ray tracing (RT) at mmWave and sub-mmWave bands, providing a more thorough understanding of the intrawagon mmWave and sub-mmWave channels.