A prior consultation took place with the French National Frequency Agency (ANFR, Agence nationale des fréquences) to develop the measurement methods most suited to providing the information on human exposure expected from this campaign. The methodology implemented has benefited from ANFR's experience on the French pilot sites. South Korea was chosen to carry out the measurements because it is the first country to start commercial development of this technology, followed closely a few months later by Australia. The deployment frequency chosen in these 2 countries is the same as that chosen in France for starting up the network, namely 3.5 GHz (3.4-3.8 GHz).
The measurements were taken at the end of November 2019, in collaboration with the NRRA, the Korean institute in charge of telecommunications regulation, 6 months after the network was opened to the Korean public. This collaboration provided an initial vision of the organization of the 5G service, made it possible to distinguish between the antennas of the different Korean operators and provided information on the distribution of antennas in the country. The measurements thus taken were measurements with a specific exposure meter at defined frequencies, including the 5G ones (exposure meter measurements), overall exposure measurements using a wideband field meter (total field), and finely detailed frequency measurements using a spectrum analyser (spectral measurements), in several different areas of activity. Given the presence of a masking effect due to the proximity to the body, the measurements from the exposure meters were attenuated compared to the field measured with a field meter (up to a factor of 5).
To be representative of the diversity of environments encountered throughout South Korea, different types of environment were identified to obtain exposure readouts:
- Dense urban residential area - Seoul;
- Dense urban business area - Seoul;
- Dense urban commercial area - Seoul;
- Urban residential area - Naju new town;
- Urban business area - Naju new town;
- Urban commercial area - Naju new town;
- Rural residential area - Naju old town;
- Rural administrative area - Naju old town;
- Rural commercial area - Naju old town.
In parallel with these areas representing different environments, it was decided to obtain readings on a Car/Bus and Train journey, since the 5G-NR technology purports amongst other things to offer high network availability on transport routes. Fixed-point readings over 12 or 24 hours were also obtained to take into account the variability in traffic over the day.
The exposure meter measurements give field values in function the services visible. The average level of exposure to 5G is higher in dense urban areas: 0.14 V/m (1.85 V/m for the total field). Over all the measurements taken in urban areas, the 5G service represents 15% of overall exposure. It is lower in rural areas: 0.02 V/m. Given the high level of temporal and spatial variability expected from this technology, field strength was also measured in the beam near an antenna whose operationality was known: 0.56 V/m on average, or in this worst case, in the order of 50% of the average global ambient level (1.04 V/m). The maximum values measured with the exposure meters range from 0.3 V/m (urban area) to 2.1 V/m (dense urban area), with a maximum of 4.1 V/m in the beam on the roof near an antenna. The maximum field strength is always below the regulatory limit value, which is a 5G frequency of 61 V/m, and the field average is well below this. Other measurements show changes over time in the field level for a given geographical point.