## 3 Numerical and Simulation Results  
In this section, the numerical and simulation results are presented. The simulation parameters used are similar to [21], for the values for the static BS power, power amplifier efficiency and dynamic power consumption per unit throughput; other parameters are shown in Table 1. As per Figures 1 and 2 earlier, we assume the cellular system radius R = 3 km and we vary the SNR from \(-\)20 dB to 20 dB. The numerical results obtained by using the theoretical approach using Equation (13) are verified by \(10^{5}\) Monte Carlo iterations based on Equation (3) for RIS. From Figure 3, when the values of the interference number and power are fixed, the antenna for RIS is set with N = 10, 30, 50 and 100, while for DAS, we set omni-channel \begin{table}
\begin{tabular}{c c} \hline
**Parameter** & **Value** \\ \hline Radius, R & 3 km \\ Number of co-channel cell, M & 6 \\ Number of RIS/DAS per cell, C & 6 \\ Transmit power, \(\rm{P_{T}}\) & 1 W \\ Static BS power, \(\rm{P_{BS}}\) & 7.9843 W \\ Static RIS element power, \(\rm{P_{n}}(b)\) & 6.0 mW \\ Number of RIS element, N & 10 until 100 \\ Power amplifier efficiency, \(\tau\) & 38\% \\ Dynamic power consumption per unit & 0.1 W/bps \\ throughput, \(\epsilon\) & \\ Nakagami index, m & 1 \\ Path loss exponent, \(\beta\) & 2.5 \\ Activity factor, \(q\) & 0.1 to 1 \\ Cell edge FRF & 3 \\ SNR & \(-\)20 dB to 20 dB \\ \hline \end{tabular}
\end{table} 
Table 1: Simulation parameter values. antenna per DAS cell. We can see that the ergodic capacity performance improves as the number of elements in RIS increase. The RIS-aided system also provides a higher capacity below 10 dB SNR; for instance, at 0 dB, the RIS ergodic capacity for N = 100 is at 4.8 bits/s while for DAS, it is at 2 bits/s. At a high interference area and high SNR region, 20 dB, the RIS average capacity peak is 5.5 bits/s while that of the DAS-aided system is 5 bits/s, with smaller difference in comparison to 0 dB. This is because users in the DAS system suffered from various combinations of interfering signals from co-channel DASs. In contrast, the RIS system is assumed to be capable of reflecting away the undesired signals within its own cellular system, and interferers only come from other co-channel BSs. However, for DAS, interferers can come from other co-channel interferers from other cells, either from DASs or other BSs. Figure 4 reveals that the greater the attenuation to the useful signals and interference signals (i.e., having a higher path-loss exponent, \(\beta\)), the greater the ergodic capacity in comparison to the signals with a lower \(\beta\). No difference in ergodic capacity achieved by the user from \(-20\) dB until 0 dB SNR for the RIS system at different values of path loss exponent, \(\beta\), while the ergodic capacity increases almost linearly with respect to the SNR. However, as the value of SNR increases past 0 dB, it is obvious that the performance is much better in the higher value of path-loss exponent due to the interfering signal strength received by the user becoming weaker. For a very large distance of co-channel sources (12 km in this case), the interfering signal becomes less significant as the value of path loss exponent increases. Hence, the received signal improves for higher values of path loss exponent due to less interference. In high-SNR areas at 20 dB, the average capacity tends to saturate between 7 and 10 bits/s for RIS, while for DAS, the average capacity to saturate is between 7 and 8 bits/s. Figure 5 shows the ergodic capacity against SNR curves with different traffic activity factor, \(q\). The six downlink interferers, for a zero-loaded system or traffic activity factor \((q=0)\) of interfering cells, have the highest average capacity. It is commonly known that a signal has a maximal performance when there is zero presence of interfering signals. Comparing the RIS system and DAS, as the traffic activity factor \(q\) increases, the average capacity of the RIS system drops drastically compared to the DAS.