# Performance Modeling and Analysis of LTE/Wi-Fi Coexistence
## 4 Simulation Results and Discussion  
Once MOSEL-2 language solves the model, the associated IGL package generates the numerical results. Table 4 shows the assumed simulation parameters. The simulation was run for different offered bit-rate values and by changing different parameters, until a steady-state point of the solution was reached, where results no longer change. All demonstrated results are shown against the total offered bit rate (Mbit/s). A 95% confidence interval is calculated for some results and the detailed parameters of the confidence interval are presented in Table 5.  
Two groups of results are demonstrated in this section. The first group encompasses the results to demonstrate LTE, Wi-Fi performance, as well as the overall cell performance against different types of services (Figures 4-9). All results are shown for different performance parameters against the total offered bit rate (Mbit/s). Moreover, LTE simulation results attained by MOSEL-2 are compared with the mathematical solution to validate the results. Three types of services are considered in the analysis: VOLTE, WB, and STR. In the analysis, a priority is assigned to VOLTE, as this service is crucial and needs to be urgently processed. The aggregate average bit rate is demonstrated in Figure 4, for all the suggested services in the inner zone (zone 1). Given the highest priority for the VOLTE service, it can be clearly observed in Figure 4 that the aggregate average bit rate (AABR) achieved results are maximized for VOLTE compared to the other services. Exciting results can also be observed in Figure 4 for the WB and STR services. Looking at Figure 4, one can notice that, below a 25 Mbit/s offered bit rate, the performance of STR regarding AABR is much better than WB, as the offered bit rate growths beyond the 25 Mbit/s performance of the WB improved accordingly. \begin{table}
\begin{tabular}{c c} \hline \hline
**Parameter** & **Value** \\ \hline Zones/cell, k & 2 \\ Web browsing ratio & 0.60 \\ Voice-over LTE ratio & 0.10 \\ Video streaming ratio & 0.30 \\ Web-browsing session size & 10 Kbytes \\ Video streaming session size & 50 Kbytes \\ Voice-over LTE session size & 300 Kbytes \\ Maximum cell capacity & 10 Mbit/s \\ Call rate/traffic load, \(\lambda\) & 0.42–37.6 Mbit/s \\ Alpha 1 (density of the users in zone 1), \(\alpha\)1 (ratio of zone 1) & 0.60 \\ Alpha 2 (density of the users in zone 1), \(\alpha\)2 (ratio of zone 2) & 0.40 \\ Minimum bit rate in the cell (threshold) & 1 Mbit/s \\ Service rate, web browsing (WB) & 8 sessions/s \\ Service rate, video streaming (STR) & 40 sessions/s \\ Service rate, voice-over LTE (VOLTE) & 240 sessions/s \\ Maximum bit rate of zone 1 & 10 Mbit/s \\ Maximum bit rate of zone 2 & 5 Mbit/s \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Simulation parameters. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Performance Parameters** & **Lower Bound (UP)** & **Upper Bound (LB)** \\ \hline Blocking probability & 0.0002 & 0.0004 \\ Utilization & 0.47 & 0.91 \\ Delay & 86.97 & 138.79 \\ Throughput & 4.57 & 8.77 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: The 95% confidence interval parameters. Figure 4: Zone 1: aggregate average bit rate. Figure 5: Zone 2: aggregate average bit rate. Figure 8: Throughput comparison. Figure 7: Delay with the coexistence. Figure 9: Utilization comparison. The reason for this status is that STR needs a greater bandwidth than WB and, in the analysis, it was given a higher priority over WB. However, this necessary bandwidth for real-time streaming is only achieved at lower rates (i.e., less than 25 Mbit/s). On the other hand, when the load increases, this means that more people are downloading content from the Internet, and therefore the performance of the WB is maximized. The AABR is presented in Figure 5 for the outer zone (zone 2). In this figure, very interesting results can be noticed.