Analysis of the Actual Power and EMF Exposure from Base Stations in a Commercial 5G Network

Abstract

In this work, monitoring of the transmit power for several base stations operating in a live 5G network (Telstra, Australia) was conducted with the purpose of analyzing the radio frequency (RF) electromagnetic field (EMF) exposure levels. The base stations made use of state-of-the-art massive MIMO antennas utilizing beamforming in order to optimize the signal strength at the user’s device. In order to characterize the actual EMF exposure from 5G base stations, knowledge of the amount of power dynamically allocated to each beam is therefore of importance. Experimental data on the spatial distribution of the base stations’ transmit power were gathered directly from the network by extracting information on the radio and baseband operations. Out of more than 13 million samples collected over 24 h, the maximum time-averaged power per beam direction was found to be well-below the theoretical maximum and lower than what was predicted by the existing statistical models. The results show that assuming constant peak power transmission in a fixed beam direction leads to an unrealistic EMF exposure assessment. This work provides insights relevant for the standardization of EMF compliance assessment methodologies applicable for 5G base stations.

Exposure of South Korean Population to 5G Mobile Phone Networks (3.4–3.8 GHz)

“…According to Thors et al [2017], the 95th percentile of power transmitted per beam is 7–22% of the theoretical maximum. A study by Colombi et al [2020] showed that all base stations operated at a cell‐wide power level of less than 2.5% of the maximum.…”

Compliance Boundaries of 5G Massive MIMO Radio Base Stations: A Statistical Approach

“…It may be possible to use lower values of K in the analysis, but according to the discussion at the beginning of this section, a smaller number of K would lead to a network that is not fully loaded; similar considerations are also reported in the discussion section of [20].…”

“…A value of NAPP of 0.1 in a specific direction means that during the T A the BS array would radiate in that direction only a tenth of the power it would radiate when focusing its beam using the maximum gain 100% of the time. This quantity is similar to the parameter G avg , introduced in [20], which is an average gain, obtained "experimentally", by means of the analysis of the information collected by the 5G BSs operation for 24 h over a weekday.…”

“…At the best knowledge of the authors, most campaigns are available for 4G networks [18], [19], which are in any case useful because LTE systems support beamforming. Only a very recently published paper considers a measurement campaign on 5G networks [20], but in all cases strong reductions are reported with respect to the conservative compliance value due to beamforming.…”

Study on the Appropriate Measurement Spacing for EMF Installation Compliance Assessments of a 3.5 GHz 5G Base Station

“…Note that the input power and the maximum gain given in Table 1 indicates the maximum power transmission from a BS, i.e., the full traffic case considered for a BS installation compliance assessment based on the extrapolation approach [10]- [13]. This input power of 50 dBm is also the same as one used in simulation [32] and similar to one used in measurement study of 53 dBm [33], respectively. A constant side lobe level of -30 dB stems from the antenna model defined in the 3rd Generation Partnership Project (3GPP) channel report [34].…”