# Performance Evaluation of Multi-UAV Network Applied to Scanning Rocket Impact Area +
## 6 Results
### Analysis and Comparison of Results  
Baud Rate and Throughput: In scenario 1, all nodes have a baud rate set to 115,200 bps. Throughput is higher, with an average value of 14.77 kbps. In scenario 2, the throughput decreases when the packets hop through the hub. This is due to the additional time interval required by the intermediate node to receive a packet, process its respective internal routing table and transmit it to the next node. The throughput without and with hop was measured as 8.92 kbps and 7.48 kbps, respectively, being reduced by 16.14%. The results are summarized in Table 12, which are compared with the ones obtained during tests in scenarios 1 and 2.  
Latency can be properly analyzed in scenario 2. The average difference in the transmission time between mesh and peer-to-peer topologies was 22 s. Nevertheless, more than 94% of the images were successfully transmitted between two nodes, when a hop through an intermediate node occurred. No more than 59% of the images were transmitted without any loss when an intermediate node was not available. The mesh topology network is more reliable due to the redundancy in terms of existing paths and the short distance between the nodes. The delay is due to the processing time of a hop.  
When hub failure occurred, the percentage of tests without packet loss was 16.67%. This value may give the impression that the network is unreliable but two factors must be considered. Firstly, in the particular case of a UAV compact formation, the failure of a node is an unlikely event. Secondly, when a node exits the network, the packet under processing at that very moment will be necessarily lost. Therefore, in this specific case, it is important to analyze if the network is capable of reorganizing itself, how long this procedure takes to occur and the number of packets that may be lost during reconfiguration. According to Table 12, in the case of a node failure, the average transmission time was five seconds longer when compared with operation under normal conditions. Among the 30 tests with hub failure where the loss occurred, a single packet was lost during 28 tests. During the other two sessions, four and five packets were lost. There is not a proper explanation for which there  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Scenario**} & **RSSI Average** & **Average** & **Average Transmission** & **Tests without** & **Received** & **Network** \\  & **(dBm)** & **Throughout (kbps)** & **Time (seconds)** & **Loss of Packets (\%)** & **Packets (\%)** & **Reconfiguration** \\ \hline \multirow{2}{*}{
\begin{tabular}{c} **Local** \\ 01** \\ 02** \\ 02** \\ 02** \\ 02** \\ 02** \\ 02** \\ 03** \\ 04** \\ 05** \\ 06** \\ 07** \\ 08** \\ 09** \\ 01** \\ 02** \\ 01** \\ 02** \\ 0  
was no packet loss in the remaining six tests with hub failure. Possibly this is due to the fact that the node did not transmit data during the failure. It is also worth mentioning that the network found an alternate path and remained operational in 100% of the cases where a node failed.  
In general, the experiments have shown that the network is reliable. The mesh topology has proven to be a more appropriate choice than a point-to-point topology for a multi-UAV system. Analyzing the results, it can be stated that the ideal configuration lies in using a baud rate of 115,200 bps, with two or more nodes configured as routers to ensure route redundancy and the possibility of defining alternate paths form the terms and DMs to be transmitted to the BS.