## 2 Materials and Methods
### Scenario Description  
The selected scenario is a complex indoor environment that corresponds with two floors of a new library building located on the university campus of Tecnologico de Monterrey, Campus Monterrey in Mexico. Figure 3a shows a picture of the real scenario. The first floor has workspaces in the open area, as well as within the wooden bookshelves, as can be seen in the detailed picture of Figure 3b, which represents the inner part inside the wooden shelf. The second floor has an aisle with workspaces in the left part of the scenario and three aisles to access the second floor of workspaces within the wooden bookshelves. Figure 4 shows the rendered 3D view of the simulated scenario, where all the objects within the environment have been considered. In the considered scenario, 9 Wi-Fi access points are currently installed, 6 of them located on the second-floor ceiling at a 6-m height and 3 more are placed within the workspaces inside the wooden bookshelves. These access points can be seen in the central part of the ceiling shown in Figure 3.  
From an economical and aesthetic point of view, it is desirable to reuse existing indoor access point locations in the library as new communication systems are deployed in order to provide greater capacity, higher data rates and lower energy consumption in future networks. Thus, in the proposed future scenario, we have considered that the existing current Wi-Fi access points will be mounted co-sited with 9 mmWave gNodeB (gNB) hot spots operating at 5G-FR2 and 9 WLAN 802.11 ay access points operating at 60 GHz. Figure 5 presents a schematic overview of the locations of all these proposed access points. Figure 3: Considered real scenario to analyze EMF exposure with high-user density for future wireless communications systems: (**a**) aerial view of the complete scenario with two floors and (**b**) first floor inside the wooden bookshelves. Figure 2: Flowchart of the enhanced RF-EMF exposure and regulation assessment simulation tool. The total area to be assessed by the future deployment is approximately 640 m\({}^{2}\) for the first floor, plus 60 m\({}^{2}\) that corresponds with the corridors and floor in the upper part of the bookshelves on the second floor, which is a total of 700 m\({}^{2}\) of floor space available for users. Likewise, the maximum seated workspaces in the selected area of the campus library are 202; out of which, 52 are on the second floor and 150 on the first floor. Thus, the maximum high-density occupation considered in the simulations is that all workspaces are occupied with an active user (i.e., a user making use of his/her full network capacity). Then, as the medium-density occupation, 70% of the high density is considered, which corresponds with approximately 140 active users. For the simulations, all the dispersive material properties of all the objects within the environment are taken into account for the frequency of the operation under analysis (considering the conductivity and relative dielectric permittivity). These properties are presented in Table 2[26]. Specifically, the skin tissue model is considered for tissues of high-water contents as a function of the wavelength in the air [49]. Table 3 presents the main input parameters for the 5G and Wi-Fi 802.11 ay simulation setup in the scenario under analysis. We use 64 element antennas for the access points, which is a typical value for an indoor environment at mmWave frequency bands [50], and 8 antennas per polarization for the UE antenna. For comparison purposes, a uniform power distribution per user in the scenario is considered, where each beam always transmits at the same power in the DL direction (15 dBm) and in the UL direction (10 dBm), i.e., no traffic adaptation mechanisms are applied to the power radiated by the beam. Figure 4: Rendered view of the simulated scenario by means of the 3D-RL technique. Figure 5: The 5G hot spots and WLAN 802.11 ay access points locations co-sited with the current Wi-Fi access points in the scenario under consideration.