Private Mobile Networks
A new trend, mobile private networks may become an important item in the telecommunications landscape. It relies on the implementation of 5G (or LTE) systems dedicated to specific enterprises and purposes in which the infrastructure is under the responsibility of the enterprise itself or of the venue owner (or deployed by an operator for specific use), and the frequency band is licensed locally.
What is a Private Mobile Network?
Private (or non-public) mobile networks concept is based on the use of new mobile radio systems (like LTE or 5G) for dedicated local applications, e.g. in a specific company, factory, mine, seaport or airport. There are already implementations of this type based on the LTE system, as well as some initial deployments of 5G. Speaking of private networks, it should be noted that it is a change in the approach to providing mobile services. Those networks are intended for business markets (i.e., the recipient and customer is an enterprise or institution), they are associated with a specific location, requirements, and applications.
An important aspect is “privacy”, i.e. communication closes within the enterprise and does not rely on the operator’s public mobile network. In this type of solutions, as an example, an operator with a spectrum license for global (national) use leases the band to the enterprise (alternatively there are other options for spectrum use as discussed in the next section, like CBRS or direct local licensing for the regulator), and the enterprise (or a third party — a systems integrator) implements the infrastructure and uses the resulting private network to provide service. There are, of course, examples in which traditional operators implement private networks. For instance, in Germany, Deutsche Telecom is expected to manage a large portion of those networks .
What Spectrum do They Use?
One can notice the similarity of private networks to the current market of cable operators and integrators providing Wi-Fi networks for enterprises. It should be mentioned here that the private mobile networks will not replace corporate Wi-Fi networks. To enable the implementation of local, private 5G (or LTE) networks, new band licensing models are also required. These are licensing schemes for shared spectrum bands, or dynamic spectrum access models. One such mechanism is CBRS (Citizens Broadband Radio Service), operating in the 3.5GHz band , which has recently been commercially introduced in the US, and which involves making the band locally available for use by players other than spectrum owners or incumbents. In the UK, Ofcom also introduces the possibility of local licensing of the band in the frequency range 3.8–4.2 GHz , while in Germany a similar model appeared for the 3.7–3.8 GHz band .
Where Private Mobile Networks Based on 5G Can Be Used?
Applications for private networks based on the 5G system are in the area of high-performance requirements, i.e. in the so-called “Industrial IoT” (IIoT), e.g. in production plants, logistics centers, mines or seaports. Another place for this type of solution is mission-critical systems, public safety or railway systems, where transmission reliability and safety are of high importance. What is worth mentioning here is the concept called “Neutral-Host Networks” (NHN) . One option of this solution is that the infrastructure and / or license to use the frequency band belongs to (and is managed by), e.g. the facility owner, while telecom operators provide services to their clients using leased infrastructure and resources. It is a special kind of network sharing, where the infrastructure provides an open-access basis to all operators to improve coverage and capacity indoors and hotspots.
Private 5G Networks Challenges and Open RAN
Compared to currently used Wi-Fi networks, 5G systems are more complex. The set of functionalities within 5G systems includes, among others: support for millimeter waves, advanced multi-antenna techniques (Massive MIMO), network virtualization (NFV, Network Function Virtualization), programmable networks (SDN, Software Defined Networking) or Service-Based Architecture. In this context (of systems that are more complex), there is a niche for next-generation integrators specializing in the implementation of private 5G networks that would develop their competences in these areas.
The second challenge is that the aforementioned mechanisms (like CBRS/DSA) and regulations allowing for dynamic access to frequency bands or licensing taking into account the local nature of such access, as well as the pricing model for those types of licensing, are at their early stage and have not been yet verified on a mass scale.
Finally, up to now, there is a closed telecommunications infrastructure market, and thus its availability (e.g. price) for small-scale implementations. This is where the Open RAN model comes in hand as a solution, but it is also still at the early stage of commercialization. It is strongly supported by operators and new infrastructure providers, as part of the O-RAN Alliance  (or TIP — Telecom Infra Project ). This concept is based on separating the software from the equipment, i.e. virtualization of the radio network functionality and the ability to run the system on CoTS (Commercial-of-the-Shelf) equipment and open interfaces.
The private mobile network (also called local or non-public) is dedicated to a specific enterprise or application and uses the advantages of the 5G (or LTE) system, such as high security, privacy, high reliability, performance or throughput where required being independent on the public mobile networks provided by national operators. Massive implementations of this type may cause the transformation of the entire industry, leading to the granulation of the telecommunications market. In this evolved ecosystem, the following units will play a role: traditional and local telecommunications operators, next-generation integration companies, traditional suppliers, a new type of infrastructure producers, as well as broker companies proposing local access to the spectrum (a.k.a. spectrum brokers).
Note: see another blog post with an embedded video on private mobile networks 5G Core Summit – Cloud, Fog, Private 5G
This blog-post is based on my article from mensis.pl. Please find the original article in Polish at: https://mensis.pl/sklep/magazyn-mensis-pl-nr-62-2019-wersja-elektroniczna/
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Marcin Dryjanski received his Ph.D. (with distinction) from the Poznan University of Technology in September 2019. Over the past 12 years, Marcin served as an R&D engineer and consultant, technical trainer, technical leader, advisor, and board member. Marcin has been involved in 5G design since 2012 when he was a work-package leader in the FP7 5GNOW project. Since 2018, he is a Senior IEEE Member. He is a co-author of many articles on 5G and LTE-Advanced Pro and a co-author of the book „From LTE to LTE-Advanced Pro and 5G” (M. Rahnema, M. Dryjanski, Artech House 2017). From October 2014 to October 2017, he was an external advisor at Huawei Technologies Sweden AB, working on algorithms and architecture of the RAN network for LTE-Advanced Pro and 5G systems. Marcin is a co-founder of Grandmetric, where he served as a board member and wireless architect between 2015 and 2020. Currently, he serves as CEO and principal consultant at Rimedo Labs.