Overview Current radiofrequency electromagnetic field (RF-EMF) exposure limits have become a critical concern for fourth generation (4G) and fifth generation (5G) mobile network deployment across Europe. Regulation is not harmonized and in certain countries and regions goes beyond the guidelines set out by the International Commission on Non-Ionizing Radiation Protection (ICNIRP). This project will produce specific RF-EMF exposure measurement guidance for 5G Massive MIMO (multiple-input-multiple-output) base stations which will be disseminated to technical, business and regulatory communities to support the development of effective regulation and enable 5G implementation that balances performance with public safety. Need High bandwidth mobile communication is an essential tool for wealth creation in Europe, as illustrated by demand-led compound data growth rates of 40 % per year. In Europe, exposure to RF-EMF is regulated based on the 1998 guidelines of the ICNIRP, which are recommended by the World Health Organisation (WHO). Within the European Union (EU) legal framework these guidelines are enshrined in Council Recommendation 1999/519/EC. However, certain EU member states have imposed stricter EMF exposure limits which are significantly lower than the WHO or EU recommendations. For example, in the region of Brussels the cumulative limit is 6 V/m instead of 41 V/m at 900 MHz. This more stringent exposure limit has had an impact on 4G network rollout and will be worse for 5G deployment. Proximus Belgium (Belgium’s leading mobile network operator and primary supporter of this SIP) has identified the need for robust methods to measure the realistic RF-EMF exposure from 5G base stations. Current measurements of RF-EMF exposure from third generation (3G) and 4G base stations include an exclusion zone (a compliance boundary around the base station with no access to general public), based on the assumption that the theoretical maximum power is transmitted in every possible direction for a defined time-period. However, the beamforming Massive MIMO base stations employed in 5G allow energy to be focussed in sharp high-gain beams in the direction of a specific mobile user. This means that it is difficult for operators to deploy 5G Massive MIMO on sites with pre-existing 3G and 4G base stations. Regulators, operators and 5G equipment suppliers therefore require up-to-date, reliable and agreed assessments of RF-EMF exposure levels to support consistent and effective 5G regulation and network design. Previously, EMPIR project 14IND10 MET5G developed 5G testbed capability that sought to establish metrological traceability for massive MIMO base stations and measurement capability in generating traceable known EMF measurements. This project will develop and validate these measurement techniques for RF-EMF exposure using the 5G testbeds developed under 14IND10 MET5G, make recommendations on how to properly measure RF-EMF exposure from 5G base stations using Massive MIMO and share the recommendations with the relevant technical, business and regulatory communities. Objectives The project addresses the following objectives: To establish a realistic, rigorous measurement capability for traceable RF-EMF measurement of 5G NR Massive MIMO base stations. This will include RF-EMF assessment of real-world 5G NR Massive MIMO base stations based on RF-EMF measurement and data processing methods/protocols of 5G Massive MIMO base stations. To make recommendations to the technical, business and regulatory communities (e.g. EU regulatory bodies and ICNIRP, ITU, 3GPP, CTIA, IEEE, ETSI, GSMA) on how to robustly measure RF-EMF from 5G NR Massive MIMO base stations in order to establish appropriate base station exclusion zones for 5G. Funding Statement: The results in this work come from the project 18SIP02 5GRFEX. This project has received funding from the EMPIR programme co-financed by the Participating States and from the European Union’s Horizon 2020 research and innovation programme.