On the Frequency Dependency of Radio Channel's Delay Spread: Analyses and Findings From mmMAGIC Multi-frequency Channel Sounding

TL;DR

This study investigates how the radio channel's delay spread varies with frequency across multiple environments and frequencies, proposing a unified model and finding minimal frequency dependence with some deviations from existing standards.

Contribution

It introduces a new modeling approach for multi-frequency delay spread analysis and provides insights into frequency dependence across diverse scenarios.

Findings

Delay spread shows minimal frequency dependence within confidence intervals.

Significant differences from 3GPP NR model in most scenarios.

Unified model enables better comparison of multi-frequency measurements.

Abstract

This paper analyzes the frequency dependency of the radio propagation channel's root mean square (rms) delay spread (DS), based on the multi-frequency measurement campaigns in the mmMAGIC project. The campaigns cover indoor, outdoor, and outdoor-to-indoor (O2I) scenarios and a wide frequency range from 2 to 86 GHz. Several requirements have been identified that define the parameters which need to be aligned in order to make a reasonable comparison among the different channel sounders employed for this study. A new modelling approach enabling the evaluation of the statistical significance of the model parameters from different measurements and the establishment of a unified model is proposed. After careful analysis, the conclusion is that any frequency trend of the DS is small considering its confidence intervals. There is statistically significant difference from the 3GPP New Radio (NR) model TR 38.901, except for the O2I scenario.