CAP Time Analysis

Open NetSim, Select Examples->IOT-WSN->Wireless Sensor Networks->CAP Time Analysis then click on the tile in the middle panel to load the example as shown in Figure 4‑38.

Figure 4‑38: List of scenarios for the example of CAP Time Analysis

The following network diagram illustrates, what the NetSim UI displays when you open the example configuration file.

Figure 4‑39: Network set up for studying the CAP Time Analysis

Settings done in example config file

  1. The following Environment properties are already set, as Manually Via Click and Drop.

  2. In SinkNode->INTERFACE_1(Zigbee)> Datalink Layer enable Beacon mode set Superframe Order (SO) -> 10 and Beacon Order (BO) -> 12


Figure 4‑40: Datalink layer Properties window for Sink node

  1. In Adhoc Link Properties change Channel characteristics -> Path Loss only, Path Loss Model -> Log Distance and path loss exponent -> 2.

  2. Generate SENSOR_APP Traffic Between Wireless_Sensor_1 to WSN_Sink_3 and set the transport layer protocol as UDP other properties are default.

  3. Enable Packet Trace and Plots.

  4. Set Simulation time as 100 sec.

Theoretical CAP Time Calculation

  • To find CAP time, BI is 62914.56ms -> So in 100s, two beacon frames should be transmitted at 0 & 62s.

  • Check no. of beacon frames transmitted in 802.15.4 metrics.

  • Here CFP = 0 because there is only 1 sensor.

  • CAP Time = SD – beacon time = (15728.64ms) – (983.04ms) = 14745.6ms.

  • Open packet trace and filter Control_Packet_Type to Zigbee_Beacon_Frame, users should get two zigbee_beacon_frames at 0, 62.9secs, because the time interval between two beacon frames is 62 seconds. Since we have 2 nodes so user can get 2 beacon frames for each node.

  • Since two Beacon frames are transmitted, CAP time = 2 * 14745.6ms = 29491200µs.

NetSim Results:

  • Check and compare the theoretical CAP time with NetSim simulation results in IEEE 802.15.4 metrics in Results Windows.

  • CAP time = 29491200.0000Microsec.