## 4 Results
### Discussion
#### 4.2.1 Impact of the Number of Users on the EMF Exposure  
Figure 5 shows how the electric field \(E\) (DL exposure) and the SAR (UL exposure) scale with the number of users, assuming the BSs are equipped with a fixed number of BS antenna elements (256 antenna elements). The increase of the number of users leads to an increase of both \(E\) and \(SAR\). The \(E\) and the SAR increase by 174% (from 30.2 (mV/m) to 82.8 (mV/m)) and 22.2% (from \(2.66\times 10^{-5}\) to to \(3.25\times 10^{-5}\) (W/Kg)), respectively when the number of users varies from 14 to 224 users (Table 3). \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multicolumn{1}{c}{**Scenarios**} & **\#BS Ant/uUsers** & **\# BS** & **Power (kW)** & **DL Dose** & **UL Dose** & **Total Dose** & \(\ell_{i}^{\prime}/\ell_{2}^{\prime}\) & **User Cov. (\%)** \\ \(\omega_{1,2}\) = \(\omega_{2,2}\) = 0.5 & **(\(\star\))** & **\(p\)s** & **\(p\)s** & **\(\frac{\text{W}_{\text{g}}}{\text{W}_{\text{g}}}\)** & **\(\frac{\text{W}_{\text{g}}}{\text{Kg}}\)** & **\(\frac{\text{W}_{\text{g}}}{\text{Kg}}\)** & **[-1]** & **\(p\)s** \\ \hline \multirow{8}{*}{**different \# users**} & 256/14 & 10 & 1.4 & \(1.94\times 10^{-5}\) & \(2.19\times 10^{-5}\) & \(4.13\times 10^{-5}\) & 0.87/0.98 & 100.0 \\  & 256/29 & 19 & 2.9 & \(3.11\times 10^{-5}\) & \(1.62\times 10^{-5}\) & \(4.71\times 10^{-5}\) & 0.82/0.97 & 100 \\  & 256/63 & 27 & 4.1 & \(8.13\times 10^{-5}\) & \(0.73\times 10^{-4}\) & \(1.54\times 10^{-4}\) & 0.65/0.96 & 96.9 \\  & 256/126 & 32 & 4.7 & \(1.13\times 10^{-4}\) & \(0.77\times 10^{-4}\) & \(1.89\times 10^{-4}\) & 0.58/0.98 & 96 \\  & 256/174 & 34 & 5.2 & \(1.12\times 10^{-4}\) & \(0.94\times 10^{-4}\) & \(2.06\times 10^{-4}\) & 0.56/0.96 & 96.6 \\  & 256/194 & 34 & 5.4 & \(1.12\times 10^{-4}\) & \(1.06\times 10^{-4}\) & \(2.18\times 10^{-4}\) & 0.52/0.97 & 94.8 \\  & 256/209 & 36 & 5.6 & \(1.2\times 10^{-4}\) & \(1.12\times 10^{-4}\) & \(2.32\times 10^{-4}\) & 0.58/0.95 & 95.7 \\  & 256/224 & 36 & 5.6 & \(1.28\times 10^{-4}\) & \(1.53\times 10^{-4}\) & \(2.81\times 10^{-4}\) & 0.58/0.95 & 96 \\ \hline \multirow{8}{*}{**different \# antennas**} & 16/224 & 47 & 1 & \(1.88\times 10^{-4}\) & \(0.9\times 10^{-4}\) & \(2.78\times 10^{-4}\) & 0.94/0.96 & 88.5 \\  & 32/224 & 47 & 1.4 & \(1.71\times 10^{-4}\) & \(1.28\times 10^{-4}\) & \(2.99\times 10^{-4}\) & 0.93/0.92 & 90 \\ \cline{1-1}  & 64/224 & 45 & 2.2 & \(1.34\times 10^{-4}\) & \(1.76\times 10^{-4}\) & \(3.1\times 10^{-4}\) & 0.82/0.9 & 93.8 \\ \cline{1-1}  & 128/224 & 43 & 3.6 & \(1.26\times 10^{-4}\) & \(1.72\times 10^{-4}\) & \(2.98\times 10^{-4}\) & 0.81/0.9 & 94.8 \\ \cline{1-1}  & 256/224 & 36 & 5.6 & \(1.28\times 10^{-4}\) & \(1.53\times 10^{-4}\) & \(2.81\times 10^{-4}\) & 0.56/0.95 & 96 \\ \hline \multicolumn{1}{l}{**Best compromised solution**} & 64/224 & 37 & 2.1 & \(1.1\times 10^{-4}\) & \(0.44\times 10^{-4}\) & \(1.54\times 10^{-4}\) & 0.94/0.96 & 93.5 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: bi-Objective optimization: Impact of the number of antennas elements and the number of users (\(p_{95}=95\)th percentile). \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multicolumn{1}{c}{**Scenarios**} & **\#BS Ant/uUsers** & **\# BS** & **Power (kW)** & **DL Em (mV/m)** & **UL SAR** & \(\ell_{i}/\ell_{2}/\ell_{3}\) & **User Cov.