## 4 VoLTE Scenario and Simulation Report
### Simulation Analysis
#### 4.4.1 Frame Delay Analysis  
VoIP frame delay measures the time taken for voice packets to reach their destination, reflecting the overall latency experienced by UEs during calls, which directly impacts call quality and user experience, approximating the mouth-to-ear delay [24]. Table 6 presents the single eNB frame delay mean and standard deviation values, while Figure 4 illustrates the vector analysis observed during the 60 s call.  
\begin{table}
\begin{tabular}{l l l l} \hline \hline
**Parameter** & **Good** & **Acceptable** & **Poor** \\ \hline Frame Delay (ms) & 0–150 & 150–300 & \textgreater{}300 \\ FLR (\%) & 0–0.5 & 0.5–1 & \textgreater{}1 \\ Jitter (ms) & 0–50 & 50–144 & \textgreater{}144 \\ \hline \hline \end{tabular}
\end{table}
Table 4: VoIP QoS parameters.  
Figure 3: Dual eNB simulation scenario.  
\begin{table}
\begin{tabular}{l l l} \hline \hline
**MOS** & \multicolumn{1}{c}{**Quality**} \\ \hline
5 & \multicolumn{1}{c}{Excellent} \\
4–5 & \multicolumn{1}{c}{Good} \\
3–4 & \multicolumn{1}{c}{Fair} \\
2–3 & \multicolumn{1}{c}{Poor} \\
1–2 & \multicolumn{1}{c}{Bad} \\ \hline \hline \end{tabular}
\end{table}
Table 5: VoIP QoE parameters.  
In our scenario, the \"Two-sample F-test for Variances\" is used to test the null hypothesis that the variances of the two mean datasets of each parameter are equal, while the \"Two-sample \(T\)-test Assuming Unequal Variances\" is used to examine the null hypothesis that the means of two datasets of each parameter are unequal. In the single eNB simulation, two out of ten UEs (UE[2], UE[9]) experience significant frame delays, while another two (UE[1], UE[4]) experience less significant delays. The other six UEs encounter insignificant frame delays. Table 7 presents the dual eNB frame delay mean and standard deviation values, while Figure 5 illustrates the vector analysis observed during the 60 s call.  
In the dual eNB simulation, all UEs only experience a few frame delays. There is a significant improvement in the second scenario, which is also confirmed by the statistical analysis. The F-test showed that the F value (5723.54) \(>\) F Critical one-tail (3.44); thus, we reject the null hypothesis, proving that there are significant differences in the variances of the \"frame delay\" means across the two UE simulation groups. Moreover, the \(T\)-test showed that the t Stat (1.73) \(<\) t Critical two-tail (2.30); thus, we do not reject the null hypothesis, showing that the \"frame delay\" means of the two UE simulation groups are significantly different from each other. The above statistical differences are illustrated in the vector analysis of Figures 4 and 5.  
\begin{table}
\begin{tabular}{l c c c c c c c c c c} \hline \hline
**Frame Delay (ms)/UE** & **UE[0]** & **UE[1]** & **UE[2]** & **UE[3]** & **UE[4]** & **UE[5]** & **UE[6]** & **UE[7]** & **UE[8]** & **UE[9]** \\ \hline
**Mean Value** & 6.97 & 25.29 & 351.69 & 13.20 & 70.49 & 10.48 & 6.89 & 9.22 & 5.88 & 454.31 \\
**Standard Deviation** & 3.29 & 84.45 & 200.84 & 26.85 & 4.14 & 12.47 & 5.67 & 15.22 & 2.61 & 243.18 \\ \hline \hline \end{tabular}
\end{table}
Table 6: Single eNB frame delay values.  
Figure 4: UEs’ simulated frame delay (single eNB).