## 4 Results  
This section will analyze the results obtained in the tests detailed in the previous section, comparing in terms of throughput and packet losses the different routing algorithms presented. The results showed that the Babel and OLSR protocols obtained higher throughput in both the 2.4 GHz and 5 GHz bands. Besides, the expected inverse relationship between packet losses and throughput was demonstrated since one increases while the other decreases. It was also observed that the 5 GHz band presented a faster throughput decay. Because the received power is inversely proportional to frequency and distance, the 2.4 GHz band will present a higher received power at equal transmitted power and communication distance, which will allow the maintenance of a more stable and robust communication. Only at 10 m, 40 m, and 50 m, the performance of both bands is comparable. For the 10 m point, the communication between the UAVs was direct on both bands, so propagation losses were low and communication was very stable. For the 40 m and 50 m points, the communication for the 2.4 GHz band was still direct. However, for the 5 GHz band, the communication made an intermediate hop through the relay node, decreasing the distance between the communication nodes. Throughput results can be seen in Table 3 and Figure 3. Likewise, packet loss results are shown in Table 4 and Figure 4.  
Figure 2: Real testbed FANET with relay node. (**a**) Communication before 35-m mark. (**b**) Communication after 35-m mark. Note that after the 35-m mark, communication between the 2 UAVs (UAV1 and UAV2) was performed through the relay node. Before this mark, the communication was completed through a direct path. Performance measurements were taken between the 2 UAVs every 10 m step and each measurement had a duration of 60 s. The PCs were used to monitor the network and followed their UAV. The height of the UAVs was 10 m. The first UAV (UAV1) was located at the 0-meter mark. The relay node was located at the 35-m mark. The second UAV (UAV2) was positioned for 60 s at the measurement points located 10 m from the 0-meter mark. That is, the first measuring point was located at 10 m, the second at 20 m, and so on. For the 2.4 GHz band, as shown in the results, especially in Figures 3 and 4, the routing protocols present a different behavior. OLSR switches from direct communication to relay communication between the measurement points located at 40 m and 50 m. However, both BATMAN-ADV and Babel switch between 60 m and 70 m. This can be verified by the fact that there is a change of trend in the metrics studied at these two measurement points and the corresponding change in the routing table. If we now focus on the 5 GHz band, the trend change occurs between the measurement points located between 30 and 40 m. Between these two points, communication switched from direct UAVs communication to relay mode. After this change in communication, the metrics improved, to rapidly decline again with distance. Additionally, for the 5 GHz frequency band, the maximum distance at which we were able to establish communication \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**Routing Protocol**} & \multirow{2}{*}{
\begin{tabular}{c} **Frequency** \\ **Band** \\ \end{tabular} } & \multicolumn{8}{c}{**Distance**} \\ \cline{3-10}  & & **10 m** & **20 m** & **30 m** & **40 m** & **50 m** & **60 m** & **70 m** \\ \hline \multirow{2}{*}{OLSR} & 2.4 GHz & 3.3\% & 0\% & 0\% & 27\% & 11\% & 19\% & 100\% \\  & 5 GHz & 6.6\% & 30\% & 44\% & 6\% & 20.4\% & 100\% & 100\% \\ \hline \multirow{2}{*}{BATMAN-ADV} & 2.4 GHz & 0\% & 0\% & 13\% & 22.1\% & 44\% & 73\% & 27\% \\  & 5 GHz & 14\% & 84\% & 97\% & 21.3\% & 43\% & 100\% & 100\% \\ \hline \multirow{2}{*}{Babel} & 2.4 GHz & 0\% & 0\% & 0\% & 0\% & 10\% & 35\% & 18\% \\  & 5 GHz & 8\% & 36\% & 45.9\% & 15\% & 29.7\% & 100\% & 100\% \\ \hline \hline \end{tabular}
\end{table}