Open NetSim, Select Examples ->5G NR -> UE Movement vs Throughput then click on the tile in the middle panel to load the example as shown in below Figure 4‑66.
Figure 4‑66: List of scenarios for the example of UE Movement vs Throughput
NetSim UI displays the configuration file corresponding to this experiment as shown below in Figure 4‑67.
Figure 4‑67: Network set up for studying Throughput vs. UE Movement
The following set of procedures were done to generate this sample:
Step 1: A network scenario is designed in NetSim GUI comprising of 1 gNB, 5G-Core, and 1 UE and 1 Wired Node in the “5G NR” Network Library.
Step 2: Grid Length was set to 5100 m x 5100 m.
Step 3: The device positions are set as per the table given below Table 4‑71.
| Device | UE_8 | gNB_7 | Wired_Node_10 |
|---|---|---|---|
| x- axis | 500 | 500 | 3500 |
| y- axis | 1 | 0 | 1020 |
Table 4‑71: Device general properties
Step 4: The following properties were set in Interface (5G_RAN) of gNB
| Parameter | Value |
|---|---|
| Tx_Power | 40 |
| gNB Height | 10m |
| CA Type | Single Band |
| CA Configuration | n78 |
| DL-UL Ratio | 4:1 |
| Numerology | 0 |
| Channel Bandwidth | 10 MHz |
| MCS Table | QAM64LOWSE |
| CQI Table | TABLE3 |
| Propagation Model | Urban Macro |
| Pathloss Model | 3GPPTR38.901-7.4.1 |
| LOS_NLOS_Selection | User Defined |
| LOS Probability | 0 |
| Shadow Fading Model | None |
| Fading and Beamforming | NO_FADING_MIMO_UNIT_GAIN |
| O2I Building Penetration Model | Low Loss Model |
Table 4‑72: gNB >Interface (5G_RAN) >Physical layer properties
Step 5: Set Tx_Antenna_Count and Rx_Antenna_Count as 2 and 1 in gNB properties > Interface(5G_RAN) > Physical Layer.
Step 6: Set Tx_Antenna_Count and Rx_Antenna_Count as 1 and 2 in UE properties > Interface(5G_RAN) > Physical Layer.
Step 7: In the General Properties of UE 8, set Mobility Model as File Based Mobility
Step 8: A CBR Application was generated from Wired Node 10 i.e. Source to UE 8 i.e. Destination with Packet Size remaining 1460Bytes and Inter Arrival Time remaining 1168µs.
Step 9: The Transport Protocol was set to UDP.
Step 10: Additionally, the “Start Time(s)” parameter is set to 1s, while configuring the application.
File Based Mobility: In File Based Mobility, users can write their own custom mobility models and define the movement of the mobile users. Create a mobility.txt file for UE’s involved in mobility with each step equal to 4 sec with distance 100 m.
The NetSim Mobility File (mobility.txt) format is as follows:
$time 0.0 "$node_(7) 500.0 1.0 0.0"
$time 4.0 "$node_(7) 500.0 101.0 0.0"
$time 8.0 "$node_(7) 500.0 201.0 0.0"
$time 12.0 "$node_(7) 500.0 301.0 0.0"
$time 16.0 "$node_(7) 500.0 401.0 0.0"
$time 20.0 "$node_(7) 500.0 501.0 0.0"
$time 24.0 "$node_(7) 500.0 601.0 0.0"
$time 28.0 "$node_(7) 500.0 701.0 0.0"
$time 32.0 "$node_(7) 500.0 801.0 0.0"
$time 36.0 "$node_(7) 500.0 901.0 0.0"
$time 40.0 "$node_(7) 500.0 1001.0 0.0"
$time 44.0 "$node_(7) 500.0 1101.0 0.0"
$time 48.0 "$node_(7) 500.0 1201.0 0.0"
$time 52.0 "$node_(7) 500.0 1301.0 0.0"
$time 56.0 "$node_(7) 500.0 1401.0 0.0"
$time 60.0 "$node_(7) 500.0 1501.0 0.0"
$time 64.0 "$node_(7) 500.0 1601.0 0.0"
$time 68.0 "$node_(7) 500.0 1701.0 0.0"
$time 72.0 "$node_(7) 500.0 1801.0 0.0"
$time 76.0 "$node_(7) 500.0 1901.0 0.0"
$time 80.0 "$node_(7) 500.0 2001.0 0.0"
$time 84.0 "$node_(7) 500.0 2101.0 0.0"
$time 88.0 "$node_(7) 500.0 2201.0 0.0"
$time 92.0 "$node_(7) 500.0 2301.0 0.0"
$time 96.0 "$node_(7) 500.0 2401.0 0.0"
$time 100.0 "$node_(7) 500.0 2501.0 0.0"
Step 11: Plots is enabled in NetSim GUI.
Step 12: Run simulation for 100s.
Results:
Figure 4‑68: Plot of Throughput (Mbps) vs Time (sec)
Discussion
As the UE moves away from the gNB, the Application throughput starts reducing. The maximum throughput of 10 Mbps is obtained until 40 sec. At 40s the UE is 1000m away from the gNB. Then the throughput drops to 9.3 Mbps at 40 sec and at time 48 sec (when UE is 1200m away from gNB), the throughput drops to 6 Mbps and at time 52 sec (when UE is 1300m away from gNB), the throughput drops to 3.26 Mbps and subsequently keeps dropping as till the end of the simulation as the UE continues to move further away from the gNB.