Millimeter Wave and sub-THz Indoor Radio Propagation Channel Measurements, Models, and Comparisons in an Office Environment

TL;DR

This paper compares indoor radio propagation characteristics across 28, 73, and 140 GHz frequencies in an office environment, highlighting similarities and differences in path loss and multipath behavior.

Contribution

It provides a comprehensive comparison of measurements and models for millimeter wave and sub-THz indoor channels across multiple frequencies.

Findings

Path loss exponents are similar across frequencies in LOS and NLOS.

Multipath time dispersion decreases at higher frequencies.

3GPP model overestimates path loss and cluster counts.

Abstract

This letter provides a comparison of indoor radio propagation measurements and corresponding channel statistics at 28, 73, and 140 GHz, based on extensive measurements from 2014-2020 in an indoor office environment. Side-by-side comparisons of propagation characteristics (e.g., large-scale path loss and multipath time dispersion) across a wide range of frequencies from the low millimeter wave band of 28 GHz to the sub-THz band of 140 GHz illustrate the key similarities and differences in indoor wireless channels. The measurements and models show remarkably similar path loss exponents over frequencies in both line-of-sight (LOS) and non-LOS (NLOS) scenarios, when using a one meter free space reference distance, while the multipath time dispersion becomes smaller at higher frequencies. The 3GPP indoor channel model overestimates the large-scale path loss and has unrealistic large numbers of clusters and multipath components per cluster compared to the measured channel statistics in this letter.