Instrumental assessment of mobile communication base station electromagnetic field exposure

Abstract

Introduction. Monitoring and ensuring safe operating conditions of modern base stations for occupational and general public exposure is relevant with the use of methods for measuring electromagnetic fields, which allow to assess the contribution of different sources to the overall level of the electromagnetic background, taking into account the dynamic features of base stations and the spectral electromagnetic characteristics. The aim of study is the levels of electromagnetic fields assessment from modern base stations using broadband and selective measurement methods, as well as the possibility of predicting the worst exposure conditions. Materials and methods. The levels of electromagnetic fields from base stations according to the LTE2600 standard were evaluated at the maximum transmission traffic (laboratory mearements) and at real variable traffic (field measurements). For broadband measurements, the power density (PD) was estimated, for selective measurements, the PD level in the LTE frequency channel (frequency-selective measurements) and the PD level of the reference signal (code-selective measurements) were evaluated. The theoretical maximum PD level was calculated from the maximum value of the reference signal. Results. When simulating the maximum intensity of data traffic, the PD level in the LTE channel was 94.51-101.39% of the calculated maximum value. According to field measurements, the values of electromagnetic field levels obtained from frequency-selective measurements in the LTE frequency channel were less than the corresponding values estimated from the results of broadband measurements, and were no more than 25% of the theoretical maximum. Conclusions. The use of selective approach and measurement methods made it possible to estimate the maximum possible contribution of a single source to the overall level of the electromagnetic background and to predict the worst conditions for human exposure.