5G Industrial Base Stations: Empowering 5G to Reach Deeper into Industrial Production

With the deepening application of the "5G+ Industrial Internet", 5G networks are playing an increasingly important role in enhancing the efficiency of traditional manufacturing and implementing the digital transformation of manufacturing. The 5G+ Industrial Internet has become an important force to promote the digital, intelligent, and green transformation of the industry.

In the current phase, 5G has moved from being used as an industrial campus network solution for auxiliary production to becoming an industrial field network solution for production line operations. Industry customers are integrating 5G into on-site production process control and have suggested centralizing the production line control rooms and moving them off-site, as well as using wireless PLC controllers to eliminate the need for cords. While the upper computer is moved up to a centralized place, the data will stay within the shopfloor or factory. This requires the 5G network performance to be comparable to that of the wired network, which places new requirements on the 5G network, including deterministic connection, reliable guarantee, coordination between the network and industry service, and integration of the computing resources.

To meet these requirements, ZTE has proposed the NodeEngine-based industrial base station solution. This solution, based on the basic network connections of the traditional base stations, provides enhanced assurance of deterministic connection capabilities, making it possible for 5G to penetrate into the operational technology (OT) domain of the industrial production line. It also provides capabilities such as simple commissioning, flexible network architecture, and integrated virtual PLC to ensure the value investment.

5G Industrial Base Station Solution

To meet the wireless and centralized requirements of the PLC in industrial production lines, the 5G industrial base station provides a cloud-network integrated base station solution. With a computing board added to the traditional base station, it provides functions such as precise clock synchronization, enhanced connection capabilities, deterministic delay guarantee, and support for centralized and cloud-based PLC. In addition to traditional base station functions, 5G industrial base stations offer four key features:

• Intrinsic determinism: Provides punctual and accurate data transmission services

Intrinsic determinism means the ability to provide punctual and accurate data transmission services between industrial base stations and 5G industrial CPE. This is achieved by integrating various technologies with the 5G air interface enhancement technology, such as clock synchronization for terminals and networks, precise gate control for jitter elimination, frame replication and elimination for reliability (FRER), PLC packet priority and scheduling timing orchestration, and mapping packets with different priorities to TSN priorities. To ensure latency performance, several techniques are introduced such as mini-slots, DS frame structure, URLLC service preemption, uplink pre-scheduling, SR period parameters, and DRX function. Moreover, a series of enhanced designs are performed on the 5G air interface to trade redundancy resources for high reliability. For instance, control channel enhancement, low CQI/MCS table, and repeated transmission are introduced at the physical layer to improve fault tolerance of modulation and demodulation, and reliability of data transmission, and PDCP replication is introduced at the PDCP layer to improve data redundancy.

• Reliable autonomy: Improves data transmission reliability

For 5G networking in industrial fields, dual-module connections are established through industrial CPEs while dual-frequency networking is used between industrial CPEs and industrial base stations. The FRER technology is enabled to greatly improve data transmission reliability. In addition, industrial base stations also provide "isolated site autonomy", which allows existing services to operate normally when the control plane of the base station is disconnected from the 5GC core network.

• Network-service collaboration: Enables the network to coordinate and adapt to services

On the industrial sites, there are various service scenarios, such as PLC control, AGV transport, machine vision, and data collection, which involve many service types that vary greatly. To ensure a refined guarantee of services in the wireless network, it is necessary to understand the service features and the requirements of each service for network transmission.

Industrial base stations have the capability of "accurate identification". By introducing the AI algorithm and analyzing data streams, these stations can dynamically identify service types and automatically match them with the requirements of QoS templates. Characteristics of the service flow may be further identified, such as the survival time period of the PLC service, the I frame and the P frame of the video service flow, and the size, period, and arrival time of the packet. These features can be combined with air interface scheduling technology for refined processing. This elevates the control from the traditional service flow level to the service packet-level granularity, enabling the network to coordinate and adapt to services and achieve the precision effects.

• Computing and network integration: Centralized and cloud-based PLC computing power sharing platform

In traditional industrial production lines, a physical PLC acts as a bridge between application systems such as device data and IT network information processing, and plays a crucial role in data structuration and logic control. However, this approach has some disadvantages. First, the protocols between PLCs of different manufacturers are not open, which poses challenges to the coordination and extension required by software-defined flexible manufacturing. This requires an upgrade to the application system, resulting in latency and service reliability problems. Second, the private fieldbuses of different vendors are incompatible, making interconnection inconvenient, and the field device layer is tightly coupled with the PLC, increasing the operation and maintenance costs for enterprises. Finally, the digital and intelligent transformation of enterprises requires on-site network intelligence and big data. Traditional PLC devices cannot support visual data processing services. At present, the machine vision services in the on-site network require the addition of dedicated industrial computers and servers, resulting in the complexity of on-site networking.

To address these issues, industrial base stations provide an integrated computing and network solution that decouples the computing and I/O of PLCs through the virtualization technology (Fig. 1). This allows the PLCs, machine vision, big data, and other services to share the computing platforms based on general hardware computing power. Additionally, the PLC IO function can be extended to the industrial gateway, which, together with the intrinsic determination capability of industrial base stations, normalizes the IT and OT networks to achieve flat networking on the site. This facilitates collaboration and interaction of on-site devices, achieving multi-service integration and collaboration.

Conclusion

Driven by policies and technologies, there is a growing trend towards the convergence and normalization of OT and IT in the on-site network field. ZTE's 5G Binjiang Factory in Nanjing has been exploring the application of the 5G industrial field network solution in intelligent manufacturing. On the QCell assembly line, an on-site network service platform has been built using the industrial base station solution and the 5G industrial gateway. This platform enables unified access management of southbound devices and buses in the OT domain, and IT services such as virtual PLC runtime environment and computer vision detection. This platform also provides machine vision applications, including the logic control of the manufacturing line and electronic fence, as well as northbound data interface services.

The 5G industrial base station solution makes full use of the benefits of 5G networks and address issues such as many layers of industrial Ethernet networks, many fault points, and service adjustment difficulty. This solution enables wireless PLC and allows production control to shift from PLC local multi-point, and discrete management to centralized and integrated management. It facilitates the transition of business logic from the non-compatible and closed ecological mode of traditional PLC manufacturers to the software-based and open ecological mode of cloud-based PLC. Thus, the industrial site network evolves from silos and OT local control to OICT integration that allows for flexible manufacturing and digital and intelligent production.