  The on-going digital transformation is key to progress towards a new
generation of more efficient, sustainable and connected industrial systems
allowing the so-called factories of the future. This new generation, commonly
referred to as industry 4.0, will be accompanied by a new wave of use cases
that will allow companies from logistics and manufacturing sectors to increase
flexibility, productivity and usability in the industrial processes executed
within their factory premises. Unlike typical use cases from other vertical
sectors (e.g. energy, media, smart cities), industry 4.0 use cases will bring
very stringent requirements in terms of latency, reliability and high-accuracy
positioning. The combination of 5G technology with enterprise network solutions
becomes crucial to satisfy these requirements in indoor, private environments.
In this context, the concept of 5G non-public networks has emerged. In this
article we provide an overview of 5G non-public networks, studying their
applicability to the industry 4.0 ecosystem. On the basis of the work (being)
developed in 3GPP Release 16 specifications, we identify a number of deployment
options relevant for non-public networks, and discuss their integration with
mobile network operators' public networks. Finally, we provide a comparative
analysis of these options, assessing their feasibility according to different
criteria, including technical, regulatory and business aspects. The outcome of
this analysis will help industry players interested in using non-public
networks to decide which is the most appropriate deployment option for their
use cases.
