## 5 Experiments and Results
### Performance Evaluation
#### 5.2.2 Packet Loss Rate  
Additional testing was performed to experimentally validate the packet loss rate during data transmission via IoT satellites. Similarly, the experiment was conducted in two sets, i.e., data transmission with and without the packet creation mode. Table 4 provides the packet loss rates results of the first test. According to the table, the data cached in the ground IoT terminal with a packet size of 54 B were transmitted to the data center at different test times and under various weather conditions. We compared \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Transmitted Time** & **Received Time** & **Weather** & **Data Size** & \begin{tabular}{c} **Number of** \\ **Transmitted Packets** \\ \end{tabular} & \
\begin{tabular}{c} **Number of** \\ **Received Packets** \\ \end{tabular} &
\begin{tabular}{c} **Time** \\ **Delay** \\ \end{tabular} \\ \hline
2020.12.7 8:21:30 & 2020.12.7 8:22:00 & Rain & 54 B & 20 & 18 & 30 s \\
2020.12.7 19:02:34 & 2020.12.7 19:03:05 & Rain & 108 B & 20 & 19 & 31 s \\
2020.12.8 8:21:32 & 2020.12.8 8:22:09 & Overcast & 162 B & 20 & 20 & 37 s \\ \hline \hline \end{tabular}
\end{table} 
Table 2: System time delays (without the packet creation mode). \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Transmitted Time** & **Received Time** & **Weather** & **Data Size** & \begin{tabular}{c} **Number of** \\ **Transmitted Packets** \\ \end{tabular} & \
\begin{tabular}{c} **Number of** \\ **Received Packets** \\ \end{tabular} &
\begin{tabular}{c} **Time** \\ **Delay** \\ \end{tabular} \\ \hline
2020.12.6 8:21:40 & 2020.12.6 8:22:15 & Rain & 162 B & 20 & 18 & 35 s \\
2020.12.6 19:02:31 & 2020.12.6 19:02:59 & Rain & 324 B & 20 & 18 & 28 s \\
2020.12.6 19:40:05 & 2020.12.6 19:40:38 & Rain & 486 B & 20 & 19 & 33 s \\ \hline \hline \end{tabular}
\end{table} 
Table 3: System time delay (with the packet creation mode). the data received by the data center to the transmitted data to evaluate the packet loss rate and determined that the maximum packet loss rate of 9.5% occurred on 29 November 2020, at 19:02, and the minimum packet loss rate reached 0. In general, the results demonstrated that a packet loss lower than 10% could slightly affect data application. Regarding data transmission with the packet creation mode, the transmitted data cached in the ground IoT terminal exhibited a packet size of 324 B, which were converted into two subdata packets using the packet creation mode, resulting in two 162 B subdata packets. For example, on 9 December 2020, at 8:19, the numbers of transmitted and received data packets were 54 and 52, respectively. Similarly, on 9 December 2020, at 19:00, the numbers of transmitted and received data packets reached 42 and 40, respectively, and the packet loss rates in these two tests reached 6% and 4.7%, respectively, suggesting that packet loss occurred in both packet transmission tests. Additionally, other tests, such as those conducted on 12 December 2020, at 8:19 and 13 December 2020, at 19:00, yielded similar packet loss rate results. The resulting packet loss rates in these two tests are shown in Figure 8. The packet loss rates were all evidently lower than 10%, suggesting that the introduction of the packet creation mode into the satellite-enabled IoRT network could provide high-quality monitoring data retrieved from remote areas. The results listed in Table 5 are consistent with the previous results provided in Table 3, revealing an enhancement in the remote data collection, including improvements in the time delay and packet loss rate.