computing are promising solutions for low-latency and time-critical applications. In this context, a novel mobile network architecture is presented in [213], where the radio access network (RAN) relies on Fog computing to address latency issue and leads to a more reliable system.
Cybersecurity and privacy: It is an important concern in IIoT scenarios as a heterogeneous connected environment and becomes more critical in post-Covid working trend due to worker expansion and remote working. Recent advancements in blockchain technology, wireless communication, and Edge computing offer trusted, distributed, and P2P network for failure prediction in IIoT that could improve security and intelligence of such systems [204].
Despite the fact that wireless communication is well established for some industrial use cases, heterogeneity of the connectivity landscape and its integration in the system pose critical issues in the industrial Internet. In this section, we identified some principal challenges of future wireless communication in Industry 4.0 and discuss them in the following sections.
1.9.1 Diverse Communication Requirements for Different Industrial Use Cases
As we discussed in Section 1.3, the requirements of wireless industrial Internet for various types of applications widely vary in terms of energy efficiency, deployment complexity, latency, and MAC protocols. Many wireless technologies, standards, and protocols are used in IIoT and smart manufacturing systems, and managing their coexistence in a system is still an open question. For instance, deterministic transmissions are highly important in control, process, and operation systems and should be guaranteed in coexistence with various wireless networking technologies. Additionally, issues arise due to the nature of wireless medium such as limited spectrum, shared bandwidth, reliable durability, and availability.
Altogether, E2E communication is highly challenging in industrial environment, and it highlights the necessity for management and optimization of wireless networks in Industry 4.0. The main objectives of network management for wireless industrial Internet are (1) real-time and dynamic wireless network optimization and management to offer flexible communication; (2) network resource allocation at different levels of system (equipment, production, operation and enterprise planning levels) to ensure required QoS; and (3) monitoring workflows to improve a network’s visibility and performance.
1.9.1.1 Possible Solutions
One approach to guaranteeing the required QoSs in compliance with service-level agreements is to deploy a unified middle-ware that integrates various wireless technologies tailored for individual applications. Emerging technologies such as NFV, SDN, and distributed Edge computing could be leveraged for a smart and uniform platform to enhance network management and visibility [214]. The middle-ware could also provide standard interface to integrate workflows, cellular technologies, and private networks [215]. A 5G cellular network is an example of standardized technology that copes with diverse requirements and QoS levels.
1.9.2 Challenges in Cellular and Mobile Technologies for Industrial Networking
A major wireless communication technology in the industrial Internet is cellular and mobile technologies such as 5G and B5G (Beyond fifth-generation), which are better suited to high-performance and fast motion applications in harsh environments. 5G offers E2E communication through public and private/dedicated connectivity in a highly flexible, reconfigurable, reliable, and power efficient manner. This makes it suitable for a wide range of distributed industrial use cases. Even though 5G significantly transforms wireless communication in terms of the technical requirements such as low latency, high bandwidth and data rate, and dynamically adapts with a proliferation of equipment, operations, and processes in IIoT environments, additional efforts are needed to encounter synergy between communication networks, operations, and system maintenance. In Section 1.5, we discussed cellular and mobile technologies in detail, and next we focus on the future vision to address its challenges.
1.9.2.1 Possible Solutions
Industrial 5G is not still fully widespread and available; however, various operators and companies propose solutions for future smart manufacturing based on 5G. For instance, an industrial 5G router is proposed in [216] that could provide private stand-alone 5G network in an industrial environment. A 5G starter kit is also developed in [217] as a future-proof wireless and cellular networking solutions for industrial communication and IIoT that could be deployed within sites and buildings and between factories. Various frameworks offer 5G connectivity fully aligned with the vision of Industry 4.0 and offer advanced discrete automation, flexible control over smart robot motion, and AR lenses for remote monitoring in future mining and ports [218, 219].
5 Gang is another novel networking architecture for future industrial communication that leverages SDN, Edge, and slicing technologies to combine 5G, wireless communication standards, and wired technologies in production facilities [220]. It retrofits conventional machines and advanced equipment to the network via minimal human intervention and efficiently adapts their configuration to the system requirements. Based on the capacity and needs of a smart factory, 5 Gang could work on both private and public cellular networks, and its architecture could be deployed on existing 5G architectures.
Apart from the distinguishing features of 5G and the rapid deployment of Industry 4.0, the connection density and throughput of 5G is expected to fall short of the stringent requirements of the upcoming Industry X.0. Furthermore, an increasing number of smart devices and applications in industrial environments require better power efficiency in the next generation of cellular networks. To address these challenges and to fill capability gaps of 5G, a 6G mobile network is proposed to support future cellular networks by the year 2030. To highlight the vision of connectivity with 6G, Table 1.3 compares the main parameters of 5G and 6G mobile networks. Since the standard performance metrics of 6G have not yet been identified by standardization bodies, we have shown only some provisional values [221, 222]. It should be noted that 5G assists in the deployment of Industry 4.0, but 6G will foster the potential use cases of smart industry and will exploit advanced technologies to resolve 5G limitations in the future.
Table 1.3 Comparison of 5G and 6G Cellular Networks [221, 222].
| Key Performance Indicators (KPI) | 5G | 6G |
|---|---|---|
| Peak data rate | 20 Gbps | ≥ 1 Tbps |
| Peak spectral efficiency | 30 b/s/Hz | 60 b/s/Hz |
| Area traffic capacity | 10 Mb/s/m2 | 1 Gb/s/m2 |
| Connection density | 106 devices/km2 | 107 devices/km2 |
| Network energy efficiency | not specified | 1 Tb/J |
| Latency | 1 ms | 10–100 μs |
| Jitter | not specified | 1μs |
| Mobility | 500 km/h |
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