A Study on mm-wave Propagation in and around Buildings

TL;DR

This paper investigates mm-wave propagation in indoor and outdoor environments, revealing that non-line-of-sight conditions can still provide strong coverage due to reflections and scattering, supported by measurements and simulations.

Contribution

It provides new insights into mm-wave propagation mechanisms and challenges the assumption that NLoS conditions are always problematic, using combined measurement and ray tracing simulations.

Findings

NLoS mm-wave signals can achieve good coverage due to reflections and scattering.

Limited angle-spread differences observed between LoS and NLoS scenarios.

Propagation mechanisms like reflection, diffraction, and scattering significantly contribute to received power.

Abstract

mm-waves are envisaged as key enabler for 5G and 6G wireless communications, thanks to the wider bandwidth and to the possibility of implementing large-scale antenna arrays and new advanced transmission techniques, such as massive MIMO and beamforming, that can take advantage of the multidimensional properties of the wireless channel. In order to further study the mm-wave wireless channel, where propagation shows different characteristics compared to the sub-6 GHz band, a joint measurement and simulation campaigns in indoor and outdoor microcellular environments has been carried out. The investigation highlights that the traditional assumption that mm-wave NLoS propagation is problematic is not true since significant reflections, scattering and even transmission mechanisms provide good NLoS coverage in most indoor and outdoor scenarios. This also reflects in the limited angle-spread differences between LoS and NLoS locations in some cases. Finally, the contribution of different propagation mechanisms (reflection, diffraction, scattering and combination of them) to the received power is analyzed in the paper with the help of ray tracing simulations.