CR Keep out Distance

The Cognitive Radio network you model from the example configuration file meets the following specifications:

  • A network with 1 base station and 2 CR CPEs, and a unicast application running on one of the CR CPEs.

NetSim uses the following defaults for this example:

  • The unicast application transmits data at a constant bit-rate from CR_CPE_2 to CR_CPE_3.
  • Simulation runs for 100 seconds.

To simulate the example for CR Keep-out Distance for Cognitive Radio, in NetSim:

Open NetSim and Select Examples > Cognitive Radio Networks > CR Keepout Distancethen click on the tile in the middle panel to load the example as shown in below screenshot


The following network diagram illustrates what the NetSim UI displays when you open the example configuration file see Figure 4-2.


  1. See that by default, NetSim has set a grid length of 500m X 500m.
  2. See that by default, NetSim has set the Incumbent Count to 1, the range of the operating frequency from 54 MHz to 60 MHz, and incumbent is always ON. To do so:
    a. Right-click Base_Station_1 and click Properties.
           The Cr_Bs pop-up window appears.
    b. Click INTERFACE_1 (COGNITIVE_RADIO) in the left area.
    c. Click DATALINK_LAYER in the right area.
    d. The following parameters settings have been made for this example.

    • 1 for the Incumbent count field.
    • 500, 0 for the X, Y co-ordinates
    • 54 for the Oper_Freq_Start(MHz) field.
    • 60 for the Oper_Freq_End(MHz) field.
    • 10 for the ON_Duration(s) field.
    • 0 for the OFF_Duration(s) field.

    e. Click OK. The following figure illustrates the CR_Bs pop-up window and the default settings see Figure 4-3


  3. In NetSim GUI Plots are Enabled.

  4. Simulate the CR Keep-out Distance for Cognitive Radio example. To do so:
    a. Click the Run icon located on the toolbar. The Run Simulation pop-up window appears.
    b. Retain the default settings in the Simulation Configuration tab (Simulation Time = 100).
    c. Click OK. After NetSim simulates the CR Keep-out Distance for Cognitive Radio example, NetSim displays the Simulation Results window.
  5. Interpret the results. To do so:
    a. Click CR Metrics > Incumbent metrics in the left area and check the Detailed View check box in the Incumbent metrics_Table pop-up window see Figure 4-4.
    b. Scroll right and see the value in theOperational time(Microsec) and Idle time (Microsec) column. Because the incumbent is operational throughout the simulation, you will see that the value of the Operational time is 100 seconds and that of the Idle time is zero (0) seconds. The following figure illustrates step (b). Figure4-4
    c. Click Application_Metrics in the left area and check the Detailed View check box in the Application_Metrics_Table pop-up window see Figure 4-5.
    d. See the value in the Throughput (Mbps) column. Because we set the Keep-out distance to 100 and set the incumbent coordinates to outside the Keep-out distance, there is no Interference and you see a non-zero value for the throughout. The following figure illustrates step (d)