NetSim Support Portal

Objective: To introduce UAV mobility in CR CPE devices of Cognitive Radio networks.

Steps to setup NetSim to introduce mobility options in the CR CPE devices of Cognitive Radio networks.

1. Download the CR-CPE.xml file attached herewith. Copy and replace the already existing file in <NetSim_Install_Directory>/Docs/UI_xml/Device_Properties path. 

2. Download and import open the CR-UAV-Mobility.netsimexp file in NetSim.

NetSim Scenario:

Network Properties:

Run simulation and Open the Application Throughput vs Time plot from the results dashboard and Generate plot for Application 1.

Performance Analysis:

• 0-10 seconds (Off period):

  • No Primary User on the Channel: During this time, the channel is free, meaning no primary user is occupying it.
  • Secondary User (UAV) Transmission: The secondary user, which is the UAV, takes advantage of this free channel and transmits data.

• 10-20 seconds (On period):

  • Primary User Comes onto the Channel: At around 10 seconds, a primary user begins using the channel. The secondary user (UAV) is no longer allowed to transmit to avoid interference.
  • Resulting Zero Throughput: During this time, the throughput drops to near zero, as shown by the flat line between 10 and 20 seconds. This represents the off period for the secondary user.

• 20-30 seconds (Off period):

  • Primary User Leaves: At 20 seconds, the primary user stops using the channel.
  • Secondary User Resumes Transmission: The UAV (secondary user) detects the free channel and starts transmitting again, which is shown by the throughput spiking back up to 1 Mbps.

• 30-40 seconds (On period):

  • Primary User Returns: Between 30 and 40 seconds, the primary user again occupies the channel, and the secondary user has to stop transmitting.
  • Zero Throughput: The throughput once again drops to near zero.

• 40-50 seconds (Off period):

  • Primary User Leaves: At 40 seconds, the primary user leaves the channel, allowing the secondary user to transmit again. The throughput spikes back up to 1 Mbps.

• 50-60 seconds (On period):

  • Primary User Returns: At 50 seconds, the primary user occupies the channel. Since the UAV (secondary user) is out of Keep out Distance from Primary User, UAV (secondary user) continues use the channel, since there is no interference detected.

• 60-70 seconds (Off period):

  • Primary User Leaves: At 50 seconds, the primary user leaves the channel. UAV (secondary user) continues to use the channel, since there is no interference detected.

UAV Mobility Trajectory as follows:

• Takeoff Phase (0 - 45 seconds):

  • The device starts at the point (X=150, Y=150, Z=10) and vertically ascends while maintaining the same X and Y coordinates.
  • Every 5 seconds, the altitude (Z) increases by 10 units, reaching a maximum height of Z=95 at 45 seconds.
  • The vertical takeoff is smooth, indicating the device is moving straight upward.

• Circular Horizontal Movement (50 - 145 seconds):

  • Once the device reaches the maximum height (Z=95), it begins moving horizontally in a circular pattern while maintaining a constant altitude of 95 units.
  • From 50 to 75 seconds, the device moves to the right and then curves downwards.
  • Between 75 and 100 seconds, the device moves to the left and down, reaching (X=100, Y=150).
  • From 100 to 125 seconds, the device moves left and then curves upwards.
  • Between 125 and 145 seconds, it moves to the right and back to its initial X=150, Y=150 position at 145 seconds, completing the circular movement.

The movement pattern can be visualized as shown above using a python utility which can be found at: 3D Mobility Animation in NetSim : NetSim Support Portal (tetcos.com)

Additional Resources:

1. Network Simulator, NetSim, Emulator, 5G, Military Communication, Vehicular networks (tetcos.com)
2. UAV-Simulation-MATLAB-Interfacing_v14.1.pdf (tetcos.com)
3.  LTE-UAV-Simulation-MATLAB-Interfacing_v14.1.pdf (tetcos.com)