Time-Varying Rician K-factor in Measured Vehicular Channels at cmWave and mmWave Bands

TL;DR

This paper investigates the time-varying Rician K-factor in vehicular channels across cmWave and mmWave bands, revealing its similarity across frequencies and correlation with delay spread, based on multi-band measurements in urban environments.

Contribution

It provides the first comprehensive analysis of the K-factor's behavior across multiple frequency bands in vehicular channels, highlighting its correlation with delay spread.

Findings

K-factor is similar across 3.2 GHz, 34.3 GHz, and 62.35 GHz bands.

K-factor correlates with RMS delay spread.

K-factor remains relatively stable over time in V2I channels.

Abstract

Future vehicular communication systems will integrate millimeter wave (mmWave) technology to enhance data transmission rates. To investigate the propagation effects and small-scale fading differences between mmWave and conventional centimeter wave (cmWave) bands, multi-band channel measurements have to be conducted. One key parameter to characterize small-scale fading is the Rician K-factor. In this paper, we analyze the time-varying K-factor of vehicle-to-infrastructure (V2I) channels across multiple frequency bands, measured in an urban street environment. Specifically, we investigate three frequency bands with center frequencies of 3.2 GHz, 34.3 GHz and 62.35 GHz using measurement data with 155.5 MHz bandwidth and a sounding repetition rate of 31.25 {\mu}s. Furthermore, we analyze the relationship between K-factor and root-mean-square (RMS) delay spread. We show that the Ricean K-factor is similar at different frequency bands and that is correlated with the RMS delay spread.