EMF evaluations for future networks based on Massive MIMO

Future networks will allow to reach high level of connectivity and capacity in order to respond to the growing traffic needs of the incoming years. It means that, future fifth generation of mobile network (5G) and existing fourth (4G) Long Term Evolution (LTE) network, will be characterized by a very large installations deployment in terms of macro/micro/femto cells. In addition, the introduction of active antenna technologies will permit to enhance performance in terms of capacity. This new paradigm has suggested to international standard bodies to revise RF EMF (Radio Frequency Electromagnetic Field) compliance assessment methodologies for the regulatory requirements on human exposure by using new metrics measurements, no longer based on deterministic maximum transmitted power evaluations. In this work we consider a possible application of a statistical model to calculate real emission from a Massive MIMO antenna, in the specific case of the Italian regulation on EMF, which is based on calculating the average transmitted power over a 24-hour period. From the data collected on a real 4G network, we have seen that the average transmitted power over 24 hours from base stations is approximately the 20% of the maximum transmitted power, which is typically used in the compliance assessment. By evaluations, we found that the statistical model for Massive MIMO antenna can be applied on top of the 24-hour average transmitted power evaluation obtained through network counters. As an example, the real power density @20 m with an antenna Gain of 15 dBi is always below the Italian limit for all possible transmitted power (i.e. $25 \div 35 \ \ W$ ). The new combined model of statistical MIMO power model with an EMF evaluation averaged over time, as used in Italy, is an example of how to apply new metrics for EMF emission analysis of future networks.