# Unmanned Autonomous Intelligent System in 6G Non-Terrestrial Network
## 5 A Case Study of UAV NTN Airborne Network in Mountainous Area
### Field Trial Results
#### 5.2.2 Results and Analysis  
The images in Figure 8 show the scenes of field trials in mountainous and desert areas in the western part of China. To test the quality of service (QoS) of the communication network for the ground UEs, we establish three different measurement points near the center of the flight trajectory of UAVs. The experiments have successfully verified the ability of various kinds of UEs to access the network, edge computing resources, and intelligent services without the support of ground network infrastructure. The test results of the field trial are shown in Table 6 below. At measure point A, the user equipment is in a stationary setup, 3400 m away from the UAV. The downlink is stable with RSRP above \(-90\) dBm with a maximum downlink speed of 17 Mbps and a maximum uplink of 756 Mbps. Additionally, the time delay is about 30 ms without offline phenomenon. In terms of UAV communication coverage applications, this field trial has successfully validated the UAV NTN networks for mountainous area coverage with a network edge rate of 17 Mbps, a peak rate of 756 Mbps, an average delay of 21 ms, and a total system bandwidth of 240 MHz. In order to verify network flexibility, this field trial achieved on-demand coverage of 36 square kilometers and a peak coverage of approximately 180.3 square kilometers along a mountainous area. The collaborative networking provided by three UAVs in the airspace supported broadband transmissions for 41 users, with a system outage probability of less than 0.04% (Table 7). \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**MeasurementPoint**} & \multirow{2}{*}{**Type**} & **Distance to UAV** & **Throughput** & **Downlink RSRP** & **Downlink SINR** & **Time Delay** \\  & & **(M)** & **(Mbps)** & **(dBm)** & **(dB)** & **(dB)** & **(ms)** \\ \hline \multirow{8}{*}{A} & Uplink & 3490.17 & 26.99 & \(-88.13\) & 28.81 & / \\  & Ping & 3707.13 & / & \(-97.63\) & 22.31 & 323 \\  & Uplink & 3705.50 & 10.82 & \(-101.81\) & 14.81 & / \\  & Downlink & 3654.38 & 697.34 & \(-83.13\) & 33.69 & / \\  & Ping & 3473.81 & / & \(-94.50\) & 24.69 & 23 \\  & Uplink & 3418.66 & 17.23 & \(-91.50\) & 25.19 & / \\  & Ping & 3500.57 & / & \(-85.38\) & 26.31 & 31 \\  & Downlink & 3418.87 & 756.49 & \(-84.06\) & 35.81 & / \\ \hline \multirow{3}{*}{B} & Ping & 3815.15 & / & \(-82.23\) & 34.37 & 27 \\  & Downlink & 3600.85 & 707.65 & \(-85.73\) & 28.99 & / \\  & Uplink & 3570.03 & 40.60 & \(-76.89\) & 39.07 & / \\ \hline \multirow{3}{*}{C} & Uplink & 3415.97 & 22.02 & \(-78.29\) & 39.34 & / \\  & Downlink & 3744.77 & 362.91 & \(-99.41\) & 24.50 & / \\ \cline{1-1}  & Ping & 4049.63 & / & \(-98.69\) & 25.06 & 16 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Ground UE test results of UAV NTN network field trial. Figure 8: Field trial scene of UAV airborne NTN: (**a**) quadrupedal locomotion robot with Customer Premise Equipment (CPE) on board; (**b**) CH-4 UAV equipped with 5G base station and satellite antenna preparing to take off. Various application is verified through the UAV NTN communication, including text messages, video streams, robot operation system (ROS), and so on. With the support of NTN communication, a multi-robot collaboration experiment is also conducted with quadrupedal locomotion robots. Quadrupedal locomotion robot is a novel platform that is able to move in challenging terrain from the inspiration of locomotion of legged animals, which is effective in mountainous disaster rescue scenarios. Quadrupedal locomotion robot is a useful tool for disaster relief and area surveillance in complex environments such as mountainous or remote areas. In the field trial, a group of four robots equipped with multi-spectrum image sensors and customer premise equipment (CPE) is utilized to test coordination capabilities with collective behaviour under the support of the UAV NTN airborne network. During the field trial, the robots were connected to the UAV base station to maintain data links to the operator and nearby robots.