# Satellite-Assisted Disrupted Communications: IoT Case Study
## 5 Results
### Scenario 2: IoT Sensors from Smart Santander Transmitting to Transmitting to Existing TestBeds  
Figure 6 illustrates the mean and range of RTTs, as well as the received pings and ping loss for each sensor and satellite constellation. Since every sensor communicates with different destination nodes, a direct comparison among sensors may lack significance. Therefore, we evaluate and compare the transmissions of each sensor across the different constellations.  
In all experiments within Scenario 2, the range of the RTT is more compressed when the _intersatelliteLinks_ parameter was enabled (see Figure 7), primarily due to the less frequent satellite-to-MCC connections. Consequently, we generally observed a higher mean RTT with _intersatelliteLinks_ disable. We also noticed similar values of the mean RTT in certain Sensors with and without the _intersatelliteLinks_ parameter. The most likely explanation can be found by examining the location of the destination nodes, wherein the connection between the sender and the receiver was established through one satellite, utilizing practically no _intersatelliteLinks_, although they were enabled. Moreover, Sensor[5] was identified as a distinctive case, communicating with its destination (located in U.S.) primarily with _intersatelliteLinks_ enabled and only without them through a constellation of 900 satellites.  
Regarding the received pings, noteworthy observations have surfaced. While some sensors followed the expected pattern--where an increase in planes and satellites in the constellation corresponded to an increase in received pings (e.g., Sensor[0,4])--others exhibited an inversely proportional relationship (e.g., Sensor[1,3]) and some demonstrated mix results (e.g., Sensor[2]). For the latter case, Sensor[2] received more pings within  
Figure 4: RTT (y axis) per time (x axis) for sensors 1, 5, 15 in both 360 (first row) and 600 (second row) satellite constellation for Scenario 1.  
Figure 5: Comparison of Mean RTT (**left**) and pings sent and received (**right**) per satellite constellation in Scenario 1.  
the 360 satellite constellation compared to the 600 one, but fewer pings in contrast to the 900 satellite constellation. We attribute the results of Sensors[2; 3; 6] both to the possible occurrence of occupied communication channels but also to the topology of the experiment.  
A potential indicator of the occupied communication channels case could be the significant variations in the RTT. In such occasions, transmissions may take longer to reach the destination because they either attempt a more distant idle path or transmit at a subsequent point in time when a communication channel is available, utilizing the \"store-and-forward\" mechanism. Both scenarios contribute to longer RTTs, which are observable in RTT/time diagrams. This phenomenon was noticeable in Figure 7c for Sensor[2], where the RTT values were increased even up to six times at certain time points and then returned to their average values.  
On the contrary, the ping loss experienced by Sensor[3] can be attributed to the positioning of the ground station in relation to the orbits and satellites within the constellation. Specifically, Sensor[3] transmitted from Smart Santander to a testbed in Ireland, a communication link that was challenging to establish with the specific type of constellation (i.e., planes and satellites per plane), the satellites' communication range and the related preconditions as described in Section 4.1. This is observed in the simulation snapshot depicted in Figure 6.  
Figure 6: Comparison of Mean RTT (**left**), pings sent and received (**right**), and % ping loss (**below**) per satellite constellation in Scenario 2. Each color represents a different constellation i.e., 360, 600, 900 satellites.