# Communication Interface Manager for Improving Performance of Heterogeneous UAV Networks
## 5 Experimental Setup
### Experimentation Scenarios  
For the experimentation scene, we adopted the soccer field at the main Campus of the Federal University of Santa Catarina (UFSC), in Florianopolis, Brazil (UFSC's soccer field GPS coordinate is \(-\)27.603916 \(-\)48.518370). Three experimentation scenarios were used in the proposed evaluation, containing 3, 5, and 8 UAV nodes. Each scenario depicted straight lines that represented the path to be covered by each UAV. The starting point (0x, 0y), or base point, is the point of origin (take-off) and the destination (landing) common to all UAVs (in reality, there was a few meters' difference between the two for safety reasons). Each UAV had one or two intermediate waypoints, which represented places where the UAV supposedly performs the mission before returning to the base. The adopted safety-distance was 1.5 m for scenario-1, 2.0 m for scenario-2, and 8.0 m for scenario-3, allowing them to start their missions at the same time, avoiding collisions during departure and arrival. Each vehicle had different maximum speeds to be used along the trajectory with an acceleration of 0.8 m/s\({}^{2}\), deceleration of 4.5 m/s\({}^{2}\), and an imperfection of 0.5% in the execution of the vehicle's trajectory to and from the intermediate waypoint. The total distance traveled and the maximum speeds for each vehicle are shown in the legends included in Figures 4-6. The traffic generator is composed of an on-off pattern. The duration of each of these states is determined by random time variables in intervals of up to 1 ns. During the off state, no traffic is generated. During the on state, constant bit rate (CBR) traffic is generated with packet sizes of 1472 Bytes. The interface data rate is 50 Mb/s divided by the number of nodes of scenario, due this being the nominal rate from 802.11 radios. For a fair comparison, this data rate was defined in all the evaluated interfaces, employed either homogeneously or heterogeneously. Using the nominal rate of 50 Mb/s from the interface and the defined CBR traffic, it was possible to establish a theoretical message flow limit. As the individual nodes have the theoretic maximum flow rate of 16.67, 10.00, and 6.25 Mbps for the 3, 5, and 8 nodes experiments, respectively, it would be possible to send 1735.11, 1041.66, and 651.04 samples of GPS coordinates, respectively, which have 9600 bps of resolution. If analyzing this traffic as a video streaming with 480p resolution (640 \(\times\) 420) using a minimum bitrate of 500,000 bps of a video in MP4 format, it would be possible to send this network at 33.33, 20, and 12.5 fps in the 3-, 5-, and 8-node scenarios, respectively. All developed experiments are let available for download at Github [42]. Scenario-1 is illustrated in Figure 4. This scenario had an area of circa 2200 m\({}^{2}\), where each UAV had its course of a 215.41 m traveled distance. Each vehicle had its own trajectory and speed: UAV-1, 20 m/s; UAV-2, 30 m/s; and UAV-3, 10 m/s. In this scenario, the UAVs were initially positioned with distances between them up to 1.5 m, as shown in the start waypoint column values inside parentheses in the legend of Figure 4. The total distance course for UAV-1 was 66.25 m, 100.06 m for UAV-2, and 49.10 m for UAV-3. The UAVs flew to the intermediate waypoint and returned to the start waypoint. So, the distance was the same both ways. Figure 5 presents scenario-2, which used 5 nodes. This scenario covered an area of circa 2500 m\({}^{2}\), where the UAVs traveled a total of 583.62 m. The purpose of this scenario was to increase the message traffic volume and to add a larger number of waypoints and UAVs. This was performed in an area within the range limit of the adopted interfaces, IEEE 802.11n 2.4 GHz and IEEE 802.11p 5 GHz, without the need for gateways, relays, roadside units (RSU), or other range-extender devices. In scenario-2, the total distance course for UAV 1 was 49.94 m with a 10 m/s maximum speed.