## 3 Materials and Methods
In simulations, the emission consisted of three directive beams pointing to every user in each sector; the output power of the beam was evenly split to each user as shown in Figure 5 below:  
Figure 4: Antenna gain pattern (**a**) Horizontal plane; (**b**) Vertical plane. Figure 3: Spectrum emission masks of 5G transmitters (**a**) BS spectral emission mask; (**b**) UE spectral emission mask. The value 41 dBm/33 MHz was obtained using the following expression:  
\[P_{\rm 33\ MHz}=22+10*\log(8\times 16\times 2)-10\log(3) \tag{1}\]  
where 22 (dBm) is conducted power per element, 8 \(\times\) 16 \(\times\) 2 (equals 256 in total) is the number of antenna elements (i.e., power per H/V polarized element) and 3 is the number of beams. The simulations adopted a TDD duplex with 75% BS and 25% UE activity factor. It should be noted that TDD was synchronized and all 19 BS were active/inactive simultaneously. Such synchronization is the most realistic case since asynchronous TDD with Bernoulli distribution would lead to inter-cell interference within the 5G network. The network loading factor used in this study was configured as 50% which normally represents a small area analysis for the worst-case scenario. However, it should be noted that in a small area with a few IMT transmitters, if the loading approaches 50%, then the IMT network performance would not be sufficient (e.g., dropped calls will occur) and more capacity will need to be installed. Therefore, in practice, the network loading factor will most likely be less than 50%. This network loading factor was chosen in accordance with ITU-R Working Party 5D characteristics for IMT-2020 that are used in the current study cycle. The propagation was calculated according to Rec. ITU-R P.2001 and 20% of the time was configured. The simulation scenarios take into account additional clutter losses which were configured according to Rec. ITU-R P.2108. For the 5G network urban deployment scenario 65% of locations were configured, whereas for the suburban deployment scenario 15% of locations were configured. For the fixed service, no clutter was considered for the 60 m height stations, whereas for the 20 m height 50% of locations were considered; it should be noted that for the 20 m stations 50% of locations were considered only for the interfering link, whereas for the wanted link no clutter has been considered since point-to-point stations are designed so that that Fresnel zone is free of any obstructions. In the studies, a Monte Carlo simulation with 2000 events is performed to assess the linear average interference-to-noise ratio (\(I/N\)) and signal-to-interference ratio (\(C/I\)) when analyzing interference from the cluster of 5G cells to the FS receiver. After each simulation, the distance between the FS receiver and the edge of the 5G cluster was changed and the simulation was re-run until the above-mentioned criteria were fulfilled. Such an approach allowed calculating required separation distances between the 5G network and FS receivers. The interference was evaluated through the SEAMCAT simulator [17; 18]. Figure 6 below shows the example of interference simulation from 5G to FS receiver in SEAMCAT where the interference from BS 5G and UE 5G is simulated. Figure 5: Beam distribution used in simulations and gain pattern of each beam. The interference from the \(i\)th active 5G BS or the \(j\)th active UE to the FS receiver can be calculated by the following equation [19]:  
\[I_{\text{BS/UE}}=P_{TX}+G_{IMT}+G_{\text{FS}}-L_{p}-L_{\text{q}\
eq r} \tag{2}\]  
where, \(P_{TX}\) is the transmitted power of the IMT BS or UE (dBm); \(G_{IMT}\) is the transmit antenna gain of the IMT BS or UE towards the victim receiver (dBi); \(G_{\text{FS}}\) is the receive antenna gain of the FS towards the interfering station (dBi), \(L_{p}\) is the propagation loss from the IMT BS/UE to the FS receiver (dB), \(L_{\text{q}\
eq r}\) is the polarization loss (dB). At each simulation event interference from every beam of 5G was calculated.