## 4 Impact of Network Latency on Teleoperation
### CAV Teleoperation Requirements
\begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline
**References** & **Scenarios** & **Latency Thresholds** & **Data Rates** \\ \hline
[93] & Real-time streaming on LTE & DL median 100 ms streaming frames & 0.5 Mbps, 1 Mbps, and 4 Mbps \\ \hline
[103] & Remote driving using 3G & DL: avg. 121 ms video streams & N/A \\ \hline
[29] & Conduct remote driving prototype in a controlled lab environment. The delay is manually simulated to match LTE measured delay & 100 ms for video transmission & UL: 16.02 Mbps, DL: 7.43 Mbps \\ \hline
[4] & 14-mile drive in Scotland, UK, across the city’s outskirts, mixing urban, secondary roads, and a highway over 4G networks & Avg. video streaming 648 ms \(640\times 480\) pixels and 563 ms \(640\times 480\) pixels video & N/A \\ \hline
[41] & ROS-based video streaming during remote driving, WiFi with TCP and UDP protocols & UDP video streaming 720P with 50 ms & N/A \\ \hline
[91] & Single-cell 5G network that covers a 3-lane highway scenario & UL 100 ms, DL 20 ms & UL: 32 Mbps, DL: 0.4 Mbps \\ \hline
[104] & Driving locations for multiple paths & 170 ms minor impact, 700 ms significant impact. & N/A \\ \hline
[105] & Remote driving in a slalom course, setup with several traffic cones & 3G: video 205 ms and control 217 ms; 4G: video 183 ms and control 110 ms & N/A \\ \hline
[21] & Parking, snake, pylon and long track & At least 300 ms & N/A \\ \hline
[32,106] & Direct remote steering, indirect remote driving instructions & UL: 100 ms, DL: 20 ms & UL: 32/36 Mbps, DL: 0.4 Mbps \\ \hline
[32,107] & Virtual digital twin remote driving & UL: 10–50 ms, DL: 10–66 ms & UL: 8–50 Mbps, DL: 5 Mbps \\ \hline
[32,108,109] & Remotely controlled manoeuvring, path-based driving; unexpected blockage on desired route/parking lot of vehicle, overcoming obstacle, trajectory-based driving, rural road or highway & UL: 40–80 ms & UL: 10–50 Mbps, DL: 0.5 Mbps \\ \hline
[32,110] & Vehicle enters a roadblock or blocking scenario & UL: 120 ms, DL: 80 ms & N/A \\ \hline
[24,32] & Direct remote steering, indirect remote driving instructions & 300 ms & UL: 8–30 Mbps, DL: 0.3 Mbps \\ \hline
[32,111] & Information/support message exchange V2X, absolute speed of up to 250 km/h & UL: 5 ms, DL: 5 ms & UL: 25 Mbps, DL: 1 Mbps \\ \hline
[112] & Vehicle-to-everything (V2X) use cases & Maximum of 5 ms & UL: 25 Mbps, DL: 1 Mbps \\ \hline
[100] & Teleoperated driving with 5G & UL and DL 40 ms & UL: 3–32 Mbps, DL: 0.5 Mbps \\ \hline \end{tabular}
\end{table} 
Table 4: _Cont._uplink latency in the range of 50 to 120 ms and downlink latency in the range of 20 to 80 ms (with some outliers). As the latency becomes higher, such as greater than 300 ms, the operator performance seems to degrade, making it difficult. Further degradation is seen above 700 ms and 1 s, making teleoperating almost impossible. Similarly, regarding data rate, it can be inferred that CAVs have significantly higher uplink data needs than downlink needs. This is because CAV sensor perception (such as camera, lidar, and radar sensors) takes up more data than the control commands. The average uplink data rate can range from 8 to 50 megabits per second (Mbps), as camera data themselves take about 8 Mbps, while data rates for the downlink are in the range of 0.25 to 5 Mbps. Correspondingly, there are network QoS and other environmental requirements for CAV teleoperation not covered in Table 4, such as a bandwidth of about 30 to 100 MHz, depending on urban or rural environments, a throughput greater than 3 Mbps [65], visual quality with a minimum or average resolution of 640 \(\times\) 480 along with approximately 150\({}^{\circ}\) view angle FOV, and a fluent image of 25 to 30 frames per second (FPS) is sufficient for teleoperators [90]. Further, the service reliability is preferred to be 99% for uplink and 99.999% for downlink [32; 91]. Suppose the teleoperation service is scaled up in the coming years.