## 5 Network Model  
This section presents the network models used in this work, namely, CBS and DBS network models, and illustrates the simulation settings and parameters used to produce the results. In the context of the Radio Access Network (RAN), the typical architecture of wireless networks involves a single Base Station (BS) providing coverage and resources to users. This traditional network implementation often consists of a three-sector node, where the BS employs directional antennas in three directions, located at the BS site. This architecture is referred to as CBS network architecture. However, an alternative approach is the DBS architecture. In this architecture, the BS is divided into two units: the central unit known as the BBU, and RRH units mounted on towers situated at a distance far from their corresponding BBUs. High-speed fiber-optic links connect the RRHs to their BBUs, serving as both the power supply for the RRHs and the medium for carrying signaling [13]. The DBS architecture inherently represents the native structure of C-RAN networks, and the RRHs collect and relay the traffic back to the local VBS to handle complex processing through powerful cloud computing. The simulation parameters are shown in Table 3. The distributed RRHs share resources with users in close proximity. The RRHs are connected to their respective BBUs through high-bandwidth fiber links, also known as fronthaul links. The BBUs, in turn, establish backhaul links to the C-RAN cloud, enabling the processing of substantial data from the RRHs. The user distribution is modeled as a uniform distribution, with more than 100 users in the Region of Interest (RoI). In this simulation, HPN employs a single BS that implements a large-scale MIMO array antenna, consisting of 128 antenna elements arranged in an 8 \(\times\) 8 configuration with dual polarization, as depicted in Figure 8. The gain of the array is 30 dB, and it transmits at 46 dBm. Additionally, the LPN in DBS network architecture has a 20 dB gain and transmits at 30 dBm. The RRHs are distributed 100 m away from the BBU. The area of the simulation measures 300 \(\times\) 300 m\({}^{2}\). HPN and LPN transmitters are set at a 10 m height, and all UEs at a 1.5 m height. To carry out the simulation, a test area is selected and designed as a street canyon, as depicted in Figure 9. The street canyon exhibits a width of 50 m and is flanked by high-rise buildings on both sides. Two types of transmitters are employed for the investigation: an HPN with a massive MIMO array containing 128 elements, and a Low-Power Node with a \(4\times 4\) MIMO configuration. All transmitters are at a height of 10 m, simulating a small-cell deployment scenario. The receivers in this study, representing the mobile users, are uniformly distributed along the street at a height of 1.5 m.  
Through this simulation setup, the study aims to gain insights into the potential exposure levels to electromagnetic radiation experienced by end users in the vicinity of HPN sources compared to the LPN deployment. By considering the specific radiation characteristics and deployment scenarios, this research seeks to provide valuable guidance for ensuring the safety and efficiency of 6G network deployments. \begin{table}
\begin{tabular}{c c} \hline \hline
**Parameters** & **Value** \\ \hline Link & Downlink \\ Designated frequency & 28 GHz \\ Path loss model & As per 3 GPP Report 38.901 [50] \\ Foliage loss model & Weissberger model [52] \\ Bandwidth & Up to 500 MHz \\ Tx Power & 30–46 dBm \\ RRH gain & 15 dB \\ MIMO array gain & 30 dB \\ RRH distribution & 3 per BBU \\ Antenna type & SISO and MIMO \\ Tx height & 10 m \\ Rx height & 1.5 m \\ MIMO & 128 elements \\ Polarization & \(-45/45\) X-POL \\ RoI & 300 \(\times\) 50 m Street Canyon \\ MPE model & IEEE C 95.1-2005 model \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Network parameters. Figure 8: HPN 128-element massive MIMO simulation with \(\pm\)45 antenna polarization.