# A 5G-Based VR Application for Efficient Port Management
## 4 Demonstration and Performance Evaluation
### Remote Control of Mechanical Equipment Demonstration  
The trolley and crane system are shown in Figure 13. This experiment builds a simplified system to verify the feasibility of the proposed structure and the optimization of this structure. The construction of the system will be gradually enhanced in future projects. The VR system is connected to the PLC device and the AGV device, and commands are sent to the PLC device and the AGV device to implement the ship-to-shore cargo integration process. The overall process is as follows:  
* The laden ship and the AGV cart start from their respective starting points, go to the unloading point and stop when they arrive. * After both the ship and the AGV arrive at the unloading point, the robotic arm R1 starts to unload the cargo. * After the unloading is completed, the cargo carrier and the AGV trolley go to the loading point and stop when they arrive. * After both the cargo ship and the trolley arrive at the loading point, the mechanical arm R2 starts loading. * After the loading is completed, the carrier and the trolley return to the starting point, and the next round of the process is about to start. The real-time data of the trolley and the cargo ship are synchronized in the VR environment and the corresponding commands, such as forward, turn, and crane to grab the goods, etc., can be sent directly to the VR system. Figure 14 shows the delay measured by the time difference between sending the command in VR and the reaction time of the actual trolley and crane. We compare the latency and packet loss rate of this system in 5G and 4G network environments, and the latency rate obtained from the experiment is shown in Figure 14. The latency of the 4G network is on average 80 ms, which is far from the satisfaction level of most industrial operation requirements. The latency of the 5G network is below 20 ms, which is negligible for VR users. This latency can be further reduced to below 5 ms in a dedicated industrial 5G network designed for time-sensitive applications such as remote control and autonomous driving. Figure 13: _Cont._  
Operators can act remotely at the port side through the 5G + VR system, which greatly reduced the movement of operators and will further reduce the occurrence of accidents. For example, a remote-control operator can control a crane to move goods after arriving at a designated area. The crane can effectively avoid a series of problems such as the grab bucket instability caused by improper manual operation in the VR hoisting process. According to the investigation, the maximum data transmission rate of 4G and WiFi is generally not more than 30 M/s, while the transmission rate of 5G is above 200 M/s. The comparison of upload rate, download rate, network fluctuation, and delay between 4G and 5 Gz is shown in Figure 15. The test site is in Hongshan District, Wuhan, China. With the low latency and high-speed advantages of 5G communication technology, operators can support real-time control of the entire hoisting process, avoiding errors caused by delays in the operation process. The demonstration of grabbing goods in the VR scenario is synchronized with the demonstration of a real crane. Figure 14: System latency under 5G and 4G network. Figure 13: Real and Virtual model of crane grasping cargo. (**a**) Distant view; (**b**) Close view; (**c**) Virtual Distant view; (**d**) Virtual close view. From the above 5G and 4G network comparison experiments we can conclude that, whether in terms of effectiveness, reliability, latency or packet loss, etc., 5G networks are far better than that of 4G to meet the needs of the smart port. We experimented with driverless cars and remote control in a VR environment with a 4G network, and the network latency was basically above 100 ms, which is completely unable to meet normal production and life needs. Additionally, in the 5G network environment, the latency is almost stable below 30 ms.