# LoRaWAN Networking in Mobile Scenarios Using a WiFi Mesh of UAV Gateways
## 5 Simulation Results
### Frequency and Duration of Disconnections  
LoRaUAV is subject to the inevitable disconnection of some GNs. In this section, the frequency and duration of such disconnections is investigated and analyzed. The simulation parameters, which are reported in Table 4, were configured so that they fall within the default parameter ranges. The simulation script has been adapted to periodically check the GNs that are covered by each UAV. This information is then used to compute, for each GN, the number and duration of disconnection periods. The results of 100 runs are aggregated and reported in this section. The total average disconnection time, computed as the average of the sums of all disconnection periods of all the performed runs, is reported in Table 5 for all the algorithms. It can be noted that, on average, the activation of the CRM and of the MP algorithms effectively reduces almost by half the total experienced \begin{table}
\begin{tabular}{l l} \hline \hline
**Parameter** & **Values** \\ \hline Number of UAVs & 12 \\ Number of teams & 3 \\ GNs per team & 20 \\ \(K_{p}\) & 25 \\ Total simulation time & 3000 s \\ Simulation area & \(2000\times 2000\) m \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Parameters used for testing the frequency and duration of Disconnections. \begin{table}
\begin{tabular}{l c c c c} \hline \hline  & \multicolumn{4}{c}{**No Split**} \\ \hline
**UAVs** & \multicolumn{2}{c}{**Runs**} & \multicolumn{2}{c}{**Avg MP PRR Gain/loss**} \\ \hline  & \multicolumn{2}{c}{**Better w/ MP Better w/o MP**} & \multicolumn{2}{c}{**Better w/ MP Better w/o MP**} \\ \cline{2-5}
4 & 58\% & 42\% & +2.1\% & \(-1.5\%\) \\
6 & 53\% & 47\% & +9.0\% & \(-7.1\%\) \\
8 & 66\% & 34\% & +13\% & \(-6.6\%\) \\
10 & 77\% & 23\% & +15\% & \(-7.0\%\) \\
12 & 86\% & 14\% & +18\% & \(-4.0\%\) \\ \hline  & \multicolumn{4}{c}{**Split**} \\ \hline
**UAVs** & \multicolumn{2}{c}{**Runs**} & \multicolumn{2}{c}{**Avg MP PRR Gain/loss**} \\ \hline  & \multicolumn{2}{c}{**Better w/ MP Better w/o MP**} & \multicolumn{2}{c}{**Better w/ MP Better w/o MP**} \\ \cline{2-5}
4 & 78\% & 22\% & +4.3\% & \(-2.4\%\) \\
6 & 71\% & 29\% & +8.9\% & \(-5.9\%\) \\
8 & 69\% & 31\% & +11\% & \(-5.8\%\) \\
10 & 78\% & 22\% & +11\% & \(-5.2\%\) \\
12 & 91\% & 9\% & +15\% & \(-1.9\%\) \\disconnection time in comparison with both VSF algorithms. The VSF + CRM and the VSF + CRM + MP configurations perform almost identically. However, if we separate the total average disconnection times of the different teams, it can be seen that, while in the configuration with just the CRM, the average disconnection time is split almost equally among teams (\(\approx\)4000 s), the configuration with the MP algorithm favors team 0 and team 1 (\(\approx\)2200 s) at the expense of team 2 (\(\approx\)7500 s ). A visual inspection of the runs where long disconnection periods are experienced showed that team 2 tends toward a region of the map that is more difficult to access for the aerial mesh. Disconnections of the other teams are solved earlier in the simulation, thanks to the MP algorithm. This leads the UAV mesh to steer towards the location of team 0 and team 1, thus making recovery of team 2 less likely. As already stated, the current version of the MP algorithm suffers from the lack of global optimality criteria that can better direct the connection recovery efforts. The histogram of Figure 7 details the results for different combinations of algorithms. In order to better visualize the results, disconnection periods are grouped in bins of different lengths and colors are used to distinguish between different teams. The first observation that can be made is that all the algorithms are subject to partitions, so that GNs might get isolated even for long periods of time. This is particularly evident when the VSF algorithms are used alone. In fact, for both DF VSF and LoRaUAV VSF, the number of disconnections above 500 s constitutes a big share of the total experienced disconnections.