# Key Issues on Integrating 5G into Industrial Systems
## 3 Typical Applications in Industrial Systems
### AGV for Automatic Loading  
With ongoing changes in manufacturing and, in particular, the growing importance of internal logistics based on AGV, the use of wireless communication across industries is no longer an option but a necessity [37]. The entire workflow of the AGV system hardly requires manual intervention, so AGV has the characteristics of high automation, good flexibility, no noise, and no pollution. Therefore, AGV has a wide range of implementations in many industries. Generally, AGV consists of the following elements: a vehicle body, driving and steering components, guidance devices, load transfer devices, safety devices, power supply devices, onboard control systems, and communication devices. AGV mainly communicates with its upper control system during its operation and the communication content between them mainly includes task commands, vehicle status information, operation instructions, traffic management information, and information for interaction with peripheral devices.  
Compared to wired networks, wireless communication has the following advantages: low installation costs, little mechanical wear and tear, and the ability to provide crucial information even with moving AGVs. At present, most AGV scenarios adopt Wi-Fi technology to deliver communications between AGV cars and their upper control systems. However, due to the use of unauthorized frequency bands in Wi-Fi, it is very susceptible to interference, especially when there are a large number of metal shelves in factories, which can cause serious attenuation of Wi-Fi signals, resulting in on-site wireless networks' poor reliability, long latency, and high packet loss rate, or even AGV's disconnection [38; 39]. Similarly, due to excessive transmission delay, 4G is difficult to support real-time transmission of AGV data. Compared to Wi-Fi and 4G, the technology of 5G has such performance advantages as large bandwidth, high reliability, and low latency, which can better support AGV scenarios and promote their large-scale applications.  
However, as a wireless communication technology not designed for industrial settings, 5G still faces certain problems when applied in AGV systems. Firstly, the transmission power of 5G base stations is limited and the star-shaped topology can generate 5G communication blind spots that make it difficult to cover the edge areas or lead to communication barriers with base stations, resulting in poor signal quality for AGV vehicles that are far away from base stations [40; 41]. Meanwhile, as a wireless communication method, 5G is inevitably affected by interferences from its surrounding environments, which may lead to the loss of individual data packets and incomplete status information uploading by AGV vehicles, thereby endangering the generation of control instructions by the upper control  
Figure 2: The cyclic scanning working mode of PLC.  
system for the next steps. Similarly, partial control instructions may be received by AGV, thereby affecting its normal operation. Secondly, 5G is a consumer-level communication technology, which is not as dedicated to ensuring communication certainty as industrial-level communication protocols. It competes with base stations and can cause certain losses in system efficiency. The best-effort communication protocol is currently a hindrance to 5G. These problems may be solved in the future by improving the performance specifications of 5G [42]. Therefore, the problems that exist in the application of AGV are also a focus of this study.