Duality Between Uplink Local and Downlink Whole-Body Exposures in Operating Networks

The paper deals with the assessment of the exposure to radio-frequency fields induced by mobile networks. The study focuses on the instantaneous relationship between the power transmitted by handsets and that received from the base stations. The power measurements are extrapolated to estimate the exposure. This analysis is based on a set of more than 3.5 million collected samples covering GSM at 900-MHz and 1800-MHz carriers and universal mobile telecommunications system networks at 2100-MHz band. Globally, the study shows that the exchanged powers are much lower than the maximum allowed ones. The duality between the two is highlighted to emphasize that exposure to handsets is higher, whereas exposure to base transceiver station is low and vice versa . In GSM, the exposure from mobiles is shown to be much higher (around 60 dB) than that from base stations. Moreover, although the handset power is adapted depending on the receiving conditions, the analysis shows notable differences between 2G and 3G networks. Indeed, in 3G networks, the highest exposure is not always due to handsets compared to base-station antennas. Based on the presented approach, simple formulations can be derived to take into account real-time public exposure enclosing both devices and base-station contributions.