In Situ Assessment of 5G NR Massive MIMO Base Station Exposure in a Commercial Network in Bern, Switzerland

Abstract

This paper describes the assessment of radiofrequency (RF) electromagnetic field (EMF) exposure from fifth generation (5G) new radio (NR) base stations in a commercial NR network in Bern, Switzerland. During the measurement campaign, four base station sites were investigated and the exposure induced by the NR massive multiple-input-multiple-output (MaMIMO) antennas was assessed at 22 positions, at distances from the base station between 30 m and 410 m. The NR base stations operated at 3.6 GHz and used codebook-based beamforming. While the actual field levels without inducing downlink traffic were very low (<0.05 V/m) due to a low traffic load and low antenna input powers of up to 8 W, setting up a maximum downlink traffic stream towards user equipment resulted in a time-averaged exposure level of up to 0.4 V/m, whereas the maximum extrapolated exposure level reached 0.6 V/m. Extrapolated to an antenna input power of 200 W, values of 4.3 V/m and 4.9 V/m, respectively, were obtained, which amount to 0.5–0.6% of the reference level recommended by the International Commission on Non-Ionizing Radiation Protection (ICNIRP). In Bern, it was found that the impact of the NR network on the total environmental RF exposure was very limited; with maximum downlink, it contributed 2% on average. Finally, it was also concluded that extrapolation to the maximum exposure level can be done without prior knowledge of the radiation patterns, directly based on the measurement of the Physical Downlink Shared Channel (PDSCH) resource elements.

Radio-frequency exposure of the yellow fever mosquito (A. aegypti) from 2 to 240 GHz

“…Currently, 5G networks have started being installed and the typical values of the electric field strengths are not yet known for all situations. From measurements at 3.5 GHz in [ 47 ] a maximal electric field strength of 4.9 V/m was found at their measurement location, after scaling to a input power of 200 W on the base station. In simulations designed to decrease exposure in a 5G networks presented in [ 48 ] at 3.7 GHz, the authors of [ 48 ] expected electric field strengths between 0.0068 and 0.0233 V/m in a crowded environment.…”

EMF Exposure in 5G Standalone mm-Wave Deployments: What Is the Impact of Downlink Traffic?

“…In more detail, their exposure dataset is based on output power and actual gain that are collected through a monitoring tool managed by a network operator and installed over a set of 25 5G BSs, all of them operating up to mid-band frequencies. Aerts et al [17] design an insitu assessment for a set of 5G BSs operating in the midband range. The authors evaluate exposure by also injecting synthetic traffic on the link between the mid-band BS and the UE.…”

“…III is the selection of the underlying transport layer protocol. Although different previous works exploit User Datagram Protocol (UDP) (see e.g., [17]), we instead select Transmission Control Procotol (TCP), due to different reasons. First of all, TCP is being used by common applications [29], as this protocol provides strong end-to-end reliability guarantees, e.g., in-order delivery of application data, through different mechanisms, which include segment acknowledgments, retransmissions, flow control and congestion control [30].…”

Investigation of EMF Exposure Level for Uplink and Downlink of 5G Network Using Ray Tracing Approach

“…This methodology is unsuitable for accurate spatial mapping of EMF level for the entire site area. Field measurement using live commercial 5G site is another way for evaluating the EMF exposure (Aerts et al, 2021;Colombi et al, 2020). However, this approach has some key challenges such as the availability of site and equipment, detailed BS and device parameters, dynamic traffic and multiuser conditions (Adda et al, 2020).…”