## 5 Experiments and Results
### Performance Evaluation  
#### 5.2.1 System Time Delay  
The packet creation mode is a method that modifies large datasets into transmittable subdata before upload to satellites. Thus, we conducted two experiments to evaluate the time delay, i.e., uploading data less than 200 B and more than 200 B.  
In regard to data transmission without the packet creation mode, we set the size of a single data packet cached in the ground IoT terminal to 54, 108, and 162 B. We conducted the experiment at different times and under various weather conditions to evaluate the time delay. Table 2 summarizes the details of the field experiment. The data transmission  
Figure 7: Packet structure of data transmission.  
process from the ground IoT terminal to the data center via satellites revealed low time delays of approximately 30, 31 and 37 s for the 54, 108, and 162 B data packets, respectively, and these times were obtained without any processing. Since the whole data packet was smaller than 200 B, each packet could be transmitted at once during satellite overpass. The results of this experiment demonstrated that data smaller than 200 B could be transmitted in a highly efficient manner, and the time delay was very low.  
In regard to data transmission with the packet creation mode, the sizes of single data packets cached in the ground IoT terminal were 162, 324, and 486 B. Among these sizes, the 324 and 486 B packets exceeded the maximum satellite link bandwidth. Thus, we employed the packet creation mode to convert these data packets into subdata. The results are listed in Table 3. In this experiment, the 324 B packets were converted into two 162 B packets, and the corresponding time delay reached 28 s. Similarly, the 486 B packets were converted into three 162 B packets. The results similarly revealed that the packet creation mode could improve the time delay, yielding a value of 33 s. Notably, the result for the transmission of the 162 B data packets demonstrated the maximum time delay, likely because the time delay was influenced by many factors, such as the communication distance, but the time delay to transfer 162 B packets essentially agreed with the results for the transmission of the 324 and 486 B data packets, which were converted into two and three 162 B subdata packets, respectively. The results of the second experiment indicated that if the data packet exceeded 200 B, subpacket creation was needed, enabling the time consumption of transferring one data packet at a time to remain nearly the same regardless of the data amount.  
The findings obtained in the above two experiments are summarized in Tables 2 and 3. These tables indicate that to transfer one data packet at a time, transmission with the packet creation mode can maintain low time delays close to those maintained under transmission without the packet creation mode, indicating that the introduction of the packet creation mode could maintain the time delay at an acceptable level during data packet transmission. Thus, the data packet creation mode introduced into the satellite-enabled IoRT network is advantageous, as demonstrated by the results of these experiments.