Measurements of Human Exposure to EMF from 4G systems: some experimental issues in urban environments

Abstract

Abstract Assessments of human exposure to EMF in urban environments represent one of the most complex tasks because of the factors causing large temporal variations and spatial non-uniformities of the measurement results among which are increased number of RF sources, numerous reflections, and scattering objects. In this sense, human exposure to 4G systems became a real challenge due to its current wide spreading. Following the guidelines provided by the relevant technical standards in force, this paper describes the experimental results achieved by performing a long-term analysis for several days and weeks on three network operators and three frequency bands adopted in Italy for 4G communications. In particular, the stability of the 4G pilot signal levels, i.e. PBCH, is analyzed. Indeed, such a level is involved in the maximum extrapolation techniques which should always warrant worst-case and time-independent estimations of the maximum E field. The effects of the averaging time on raw data is evaluated for quantifying its effect on the possibility of reducing the variability of human exposure assessment based on the use of the extrapolation techniques. Another important issue that is related to exposure safety requirements is the determination of compliance boundaries from RBS transmitting antennas (when put into service), mainly estimated by measurements and calculations (or simulations) for the areas accessible by the general public. In this regard, here are illustrated examples for measurement and simulation approaches for a roof terrace exposure conditions at two different locations in Austria.