Impact of numerology on a RAN with phones, sensors, and cameras

Open NetSim, Select Examples ->5G NR -> Impact of numerology on a RAN with phones sensors and cameras then click on the tile in the middle panel to load the example as shown in below Figure 4‑61.

Graphical user interface, text Description automatically generated with medium confidence

Figure 4‑61: List of scenarios for the example of Impact of numerology on a RAN with phones sensors and cameras

Network Scenario[^3]: To model a real-world scenario, we base our simulation on the setup shown in Figure 4‑62. The link between the gNB and the L2_Switches that represents the Core Network (CN) is made with a point-to-point 10 Gb/s link, without propagation delay. The Radio Area Network (RAN) is served by 1 gNB, in which different UEs share the connectivity. We have 25 smartphones, 6 sensors, 3 IP cameras. The bandwidth is 100MHz and Round Robin MAC Scheduler. The position of the devices in the reference scenario depicted in Figure 4‑62 is quasi-random.

Figure 4‑62: Network set up for studying the with 25 smartphones, 6 sensors and 3 cameras communicating with respective cloud servers

In terms of application data traffic, the camera (video) and sensor nodes have one UDP flow each, that goes in the UL towards a remote node on the Internet. These flows are fixed-rate flows: we have a continuous transmission of 5 Mb/s for the video nodes, to simulate a 720p24 HD video, and the sensors transmit a payload of 500 bytes each 2.5 ms, that gives a rate of 1.6 Mb/s. For the smartphones, we use TCP as the transmission protocol. These connect to data base servers. Each phone has to download a 25 MB file and to upload one file of 1.5 MB. These flows start at different times: the upload starts at a random time between the 25th and the 75th simulation seconds, while each download starts at a random time between the 1.5th and the 95th simulation seconds.

Flows

(No of devices)

Traffic Rate (Mbps) Segment / File Size (B) RAN Dir. TCP ACK Dir.
Camera (UDP) 3 5 500 UL -
Sensor (UDP) 6 1.6 500 UL -
Smartphone Upload (TCP) 25 - 1,500,000 UL DL
Smartphone Download (TCP) 25 - 25,000,000 DL UL

Table 4‑60: Various parameters of the Traffic flow models for all the devices

The numerology  μ can take values from 0 to 3 and specifies an SCS of 15 × 2μ kHz and a slot length of $\frac{1}{2^{\mu}}$ ms. FR1 support μ = 0, 1 and 2, while FR2 supports μ = 2, 3. We study the impact of different numerologies, and how they affect the end-to-end performance. The metrics measured and analysed are a) Throughput of TCP uploads & downloads, and b) Latency of the UDP uploads

Settings done in example config file:

  1. For the above scenario set the following given properties:
gNB Properties -> Interface (5G_RAN)
Pathloss Model None
Frequency Range FR1
CA Type Inter Band CA
CA_Configuration CA_2DL_2UL_n40_n41
CA1
Numerology 0, 1, and 2
Channel Bandwidth 50 MHz
DL_UL Ratio 1:4
CA2
Numerology 0, 1, and 2
Channel Bandwidth 50 MHz
DL_UL Ratio 1:4
MCS Table QAM64
CQI Table TABLE1

Table 4‑61: gNB >Interface (5G_RAN) >Physical layer properties

Link Properties (All wired links)
Uplink/ Downlink Speed (Mbps) 10000
Uplink/ Downlink BER 0
Uplink/ Downlink Propagation Delay (μs) 5

Table 4‑62: Wired Link Properties

  1. The following Application properties set to the above scenario:
Sensor UL UDP
Generation Rate (Mbps) 1.6
Transport Protocol UDP
Application Type Custom
Packet Size (Bytes) 500
Inter Arrival Time (μs) 2500

Table 4‑63: Sensor Application Properties for UL UDP

Camera UL UDP
Generation Rate (Mbps) 5
Transport Protocol UDP
Application Type Custom
Packet Size (Bytes) 500
Inter Arrival Time (μs) 800

Table 4‑64: Camera Application Properties for UL UDP

Phone DL TCP
Transport Protocol TCP
Start Time (s) 1.5  + 4(t), Where, i = 0, 1, 2, ……, 48
Stop Time (s) 95
File Size (Bytes) 25,000,000
Inter Arrival Time (s) 200 (Simulation ends at 100s and hence only one file is sent)
Application Type FTP

Table 4‑65: Phone Application Properties for DL TCP

Phone UL TCP
Application Type FTP
Transport Protocol TCP
Start Time (s)

25 + 2(i−1) 

Where, i = 1, 2, ……, 25

Stop Time (s) 95
File Size (Bytes) 1,500,000
Inter Arrival Time (s) 200 (Simulation ends at 100s and hence only one file is sent)

Table 4‑66: Phone Application Properties for UL TCP

  1. The Tx_Antenna_Count was set to 2 and Rx_Antenna_Count was set to 4 in gNB > Interface 5G_RAN >Physical Layer.

  2. The Tx_Antenna_Count was set to 4 and Rx_Antenna_Count was set to 2 in UE > Interface 5G_RAN >Physical Layer.

  3. Run simulation for 100 sec. After simulation completes go to metrics window and note down throughput and delay value from application metrics.

Result and Analysis:

Numerology(μ) = 0

Camera

Uplink

Sensor

Uplink

Smartphone
Uplink Downlink
Throughput (Mbps) Delay (μs) Throughput (Mbps) Delay (μs) Throughput (Mbps) Throughput (Mbps)
4.99 1841.54 1.6 2288.68 86.92 101.68
4.99 1838.88 1.6 2290.10 86.92 101.68
4.99 1836.21 1.6 2283.00 86.92 101.68
1.6 2284.42 86.92 101.68
1.6 2285.84 86.92 101.68
1.6 2287.26 86.92 101.68
86.92 101.68
86.92 101.68
86.92 101.68
86.92 101.68
86.92 101.68
86.92 101.68
86.92 101.68
86.92 101.68
86.92 101.68
86.92 101.68
86.92 101.68
86.92 101.68
86.92 101.68
86.92 101.68
86.92 101.68
86.92 101.68
86.92 101.68
86.92 101.68
86.92 101.68

Table 4‑67: Throughput and delay for Camera, Sensors and Smartphones, When μ=0

Numerology(μ) = 1

Camera

Uplink

Sensor

Uplink

Smartphone
Uplink Downlink
Throughput (Mbps) Delay (μs) Throughput (Mbps) Delay (μs) Throughput (Mbps) Throughput (Mbps)
4.99 932.39 1.60 1538.35 173.78 156.43
4.99 930.75 1.60 1539.77 173.78 156.43
4.99 929.10 1.60 1532.68 173.78 156.43
1.60 1534.10 173.78 156.43
1.60 1535.52 173.78 156.43
1.60 1536.94 173.78 156.43
173.78 156.43
173.78 156.43
173.78 156.43
173.78 156.43
173.78 156.43
173.78 156.43
173.78 156.43
173.78 156.43
173.78 156.43
173.78 156.43
173.78 156.43
173.78 156.43
173.78 156.43
173.78 156.43
173.78 156.43
173.78 156.43
173.78 156.43
173.78 156.43
173.78 156.43

Table 4‑68: Throughput and delay for Camera, Sensors and Smartphones, When μ=

1

Numerology(μ) = 2

Camera

Uplink

Sensor

Uplink

Smartphone
Uplink Downlink
Throughput (Mbps) Delay (μs) Throughput (Mbps) Delay (μs) Throughput (Mbps) Throughput (Mbps)
5.00 477.71 1.60 782.24 347.30 151.75
5.00 476.29 1.60 783.66 347.30 151.75
5.00 474.87 1.60 776.56 347.30 151.75
1.60 777.98 347.30 151.75
1.60 779.40 347.30 151.75
1.60 780.82 347.30 151.75
347.30 151.75
347.30 151.75
347.30 151.75
347.30 151.75
347.30 151.75
347.30 151.75
347.30 151.75
347.30 151.75
347.30 151.75
347.30 151.75
347.30 151.75
347.30 151.75
347.30 151.75
347.30 151.75
347.30 151.75
347.30 151.75
347.30 151.75
347.30 151.75
347.30 151.75

Table 4‑69: Throughput and delay for Camera, Sensors and Smartphones, When μ=2

Figure 4‑63: The average uplink throughput for camera and sensors remains the same as numerology is increased. This is because the flow is UDP.

Figure 4‑64: Smartphone Uplink, and Smartphone Downlink average throughput vs. Numerology (µ)

Figure 4‑65: Camera Uplink, and Sensor Uplink Latency vs. Numerology. The latency drops as the numerology increases

For UDP applications the μ does not impact the throughput. However, higher μ leads to an obviously lower delay. The variation of delay vs. μ is as follows:

Avg Delay (Camera) Avg Delay (Sensor)
μ=0 1.838 ms 2.286 ms
μ=1 0.930 ms 1.536 ms
μ=2 0.476 ms 0.780 ms

Table 4‑70: Variation of delay vs. numerology for Camera and Sensors

The TCP throughput is inversely proportional to round trip time. Therefore, for applications running over TCP the throughput increases with higher numerology. This is because higher Numerology leads to reduced round-trip (end-to-end) times.