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IEEE CTN
Written By:

Wade Sarver, Solution Manager at Nokia and Consultant at Techfecta

Published: 26 Apr 2022

network

CTN Issue: April 2022

A note from the editors:

In December of 2012 Rio Tinto revealed that it was ready to build a private LTE mobile network at its West Angelas iron ore mine in Western Australia.  With this news, mining companies started a race to deploy cellular based private networks that since then have provided significant benefits to their operations, including production automation, improved safety, and better overall corporate financial performance.  Today there are dozens of mines around the world running either private LTE or even private 5G networks.  But mining is not the only vertical that has benefited from a move to private cellular networks, in fact, private cellular networks have been gaining traction globally in large part driven by this promise of better performance and a more secure enterprise network.  For the last decade many companies have been developing solutions that can support a multiplicity of verticals, and industry associations have come together with the purpose of developing requirements and architectures that can drive standards, and the development of product solutions.   Spectrum is being released globally for this use, while traditional operators are also developing solutions utilizing license and unlicensed spectrum.  

In this article, Wade Sarver provides his “boots on the ground” perspective on private cellular networks, based on his vast experience supporting businesses develop solutions to match their requirements, and getting them to understand the adjustments needed in their organizations to operate these networks effectively.  So, what’s the state of maturity for these solutions?  Read on to find out.

Miguel Dajer, CTN Editor in Chief

A Wireless Private Network Overview from the Eyes of a Network Planner

What Is a Private Network?

It is a network purposely built to meet an entity’s needs for improved communication services over more traditional solutions. The “entity” may be a private or even public business, a campus, building, warehouse, or anything that requires a communications network to perform tasks specifically defined for the particular type of business. Private networks have been around for a long time, from traditional wired IT networks plus Wi-Fi to the more ambitious 4G, and now 5G, private solutions.  As spectrum is released globally for private unlicensed use, we will see more efforts around these types of solutions as they offer new benefits to the enterprise.  In the rest of this article, I will provide the reader with my personal experiences and perspectives on this important and up-and-coming segment of wireless communications.

Figure 1:  High Level Private LTE architecture diagram (source: https://www.private-lte.net/)
Figure 1: High Level Private LTE architecture diagram (source: https://www.private-lte.net/)

Who Has Private Networks?

Probably you! The biggest difference between public and private LTE/5G is that the private cellular network (PCN) gives organizations an unparalleled level of reliability and control over their data and how the network is used. All businesses today, big and small, have a private network, this been common practice for the longest time. In fact, it’s so common that when someone speaks of private networks today, people forget they already have a private network; their thinking automatically goes to private LTE (PLTE) or 5G (P5G). This is how much the definition of “private” networks have become synonymous with wireless networking. In the US, the FCC has been trying to democratize spectrum by offering a part of C Band, Citizens Broadband Radio Service or CBRS, as a shared spectrum managed by a Spectrum Access System or SAS (learn more here), and also by opening up new spectrum for unlicensed use.  This democratization will help move traditional enterprise private networks to a more flexible solution with the inclusion of these cellular-based solutions.

A Tiny SAS Primer

As just mentioned, the FCC has released CBRS spectrum in the 3.5 GHz band range that has a unique setup. This spectrum can be deployed without obtaining an official license per se, but by signing up for coordination through the SAS services (learn more here), and its purpose is to ensure that the spectrum in the General Authorized Access (GAA) portion of the spectrum is coordinated and shared properly. We call this arrangement “lightly licensed” because it’s giving out spectrum that is actively managed by SAS providers ensuring that interference is mitigated, and access is coordinated.  It is a good system and a great experiment for the FCC, enabling the common business to create new business models. Think of it this way: it’s a subscription service for frequency coordination.

Figure 2: A view of the three tier access priorities managed by SAS  (Source: https://www.comsearch.com/products/dsa/cbrs/)
Figure 2: A view of the three tier access priorities managed by SAS (Source: https://www.comsearch.com/products/dsa/cbrs/)

So Why the Push for Private Carrier-Grade Networks?

Why not just Wi-Fi?  The pros and cons of having a carrier-grade wireless private network have been documented extensively, here I provide you with my perspective based on personal experiences designing and deploying these networks:  

Pros:

  • Carrier-grade network. This means that the network is connected to core and edge servers offering more advances in the future than Wi-Fi.  Additionally, Wi-Fi solutions operate in unlicensed spectrum and therefore are at risk of interference, whereas dedicated and licensed private networks utilize managed spectrum that helps avoid such issues.
  • Security. Carrier-grade networks are perceived (and probably have) better security than Wi-Fi solutions.  Unlike Wi-Fi based private networks, cellular-based networks required a SIM to allow access followed by authentication. Wi-Fi networks have become more secure over the last few years, but still don’t match the level of a carrier-grade cellular network. 
  • Latency. With 5G, latency is much reduced. This helps with the responsiveness of different services, but the real value is with the IIoT applications and URLLC type services required in many verticals.
  • Network slicing. This 5G capability is used to reserve portions of the network for specific use cases. Just think of a slice being used for IoT and another slice being used for video.
  • Mobility. This is a slight benefit as mobility is well implemented in cellular systems, but it is unclear whether all types of enterprises will significantly benefit from it.
  • IIoT. LTE and 5G offer much better IoT solutions compared to Wi-Fi. Wi-Fi does have solutions for some applications like video and for certain devices like thermostats, but it doesn’t offer as much for applications requiring low power (e.g., metering, control, motion sensors, etc.).
  • Fewer wireless access nodes. CBRS spectrum offers a higher power capability than Wi-Fi. This yields a network design with fewer access points, albeit more complex ones, and this is particularly true in larger campus-type applications with indoor and outdoor requirements.
  • Roaming. Users can roam from the private network to a public network in a very secure manner.
  • IT/OT integration. A private network, being separate from an enterprise’s IT network, can potentially make it easier to deploy applications in the OT (operational technology) world - machines, electromechanical devices, manufacturing systems, and other industrial equipment.

Cons:

  • Bandwidth. At least today, Wi-Fi has more spectrum and offers more broadband access than PCNs
  • Cost. A carrier-grade network will add cost: CapEx (radios and edge servers) and OpEx (licensing, software upgrades, and core services).
  • Internal management. For a team to build and maintain their own network, they have to gain new skill sets. This is an additional expense that needs to be considered. Wi-Fi needs to be managed, but most IT departments are trained to handle it, whereas PLTE and P5G networks require different skill sets let alone a very different set of tools. If a team wants to build their own core and not offload it, then additional expenses for maintenance and management are to be expected.

We Have Spectrum, Now What?

Auction 105 was the first CBRS auction to take place, on July 23rd, 2020. This marked the availability of 150 MHz of spectrum that can be used for a number of shared services including private networking.  Similarly, in November 2019, Germany opened 100 MHz in the 3.7-3.8 GHz band for 5G local spectrum licenses, and other countries are following suit.  It’s exciting to see the new business cases that are planning to use this type of spectrum. So many, in fact, that even traditional carriers are making plans to play in this spectrum, utilizing CBRS spectrum alongside their own.  As a side note, although we have been focusing on CBRS type spectrum, private networks can also be deployed in traditional licensed and unlicensed spectrum.

Figure 3. Band 48 Allocation (source: https://www.private-lte.net/)
Figure 3. Band 48 Allocation (source: https://www.private-lte.net/)

5G is ushering in new business models that were not viable with prior “G” generations. With private enterprises able to access high-quality spectrum and deploy carrier-grade networks, opportunities are opening for enterprises to create their own solutions in areas like transportation, logistics, manufacturing, mining, and utilities, that are not properly served by traditional carriers.  This spectrum affords businesses a great opportunity to try new models. Even companies in agriculture for instance, are excited (articles on 5G and agriculture can be  found here and here). This doesn’t mean the end of Wi-Fi, but rather it provides an alternative.  It’s not displacing other networks, but working in harmony with them. CBRS enables building one’s own business case, for specific needs, with solutions that remove most limitations.

Private Cellular Networks Sound Complicated

Deploying a PCN sounds complicated, but it’s not that much different than Wi-Fi. In fact, private cellular is in some ways easier to deploy because it uses an exclusive spectrum that’s not prone to interference and offers greater coverage. The complexity of a private 4G/5G network results from the traditional way in which corporations run IT departments and what these departments are used to manage. “There’s tremendous interest in private wireless, but they still see it as somewhat complex and that’s why we are trying to simplify that for them,” said Kurt Schaubach, CTO of Federated Wireless, which is one of the companies certified to manage CBRS spectrum. Companies like Federated are trying to simplify complexities by launching “connectivity-as-a-service” solutions to offload customers from the complexities of managing these networks.

Use Cases, Who Would Want One of These Networks?

A lot has been published about 4G and 5G support for verticals, the same type of use cases can translate to the private cellular domain. The list below are domains I have been involved in, with some more real than others in terms of readiness.  Many entities are just curious about what can be done and test the waters by issuing RFQs/RFPs, others are more serious and indeed plan to start making a migration to architectures based on PLTE or P5G.  This exercise creates opportunities to understand the gaps in technology and the internal readiness of businesses to undertake the journey. 

Educational Outreach

What is educational outreach? It’s where a school will build and extend its network to reach students at home. “Private networks can bridge the digital divide bringing equity and broadband, providing Internet service to students who are learning remotely, who live near a service provider, a carrier, or where Internet service is not good, or they just cannot afford it”, said Prash Ramani from Motorola Solutions. In states like California, legislation requires that all or no student be taught; this was exacerbated during the peak of the COVID pandemic, which drove school districts to spend money to expand their network to students' homes using PLTE. Given the complexities of managing such network, school districts are utilizing third parties to manage the traffic off-loads.  Schools pay to install the radios, mounting structures, and edge routers, while their local network supports the teachers. The students have a CPE on CBRS that can mounted on a suitable location, usually a window, providing Wi-Fi inside the home. In this case, PLTE acts as backhaul extension of the school’s network.  As an example, the city of South Bend recently announced a partnership agreement to trial CBRS-based connectivity to students (link here).

Enterprise/Campuses/Warehouses

Enterprise, which is a broad category, is herein defined as a business that can have a building, offices, warehouses, a campus or a combination. There is a variety of use cases under this category, but they all have a common trait: one network to service all the needs of the enterprise.  A PLTE or P5G network allows the network owner to manage certain capabilities like coverage, types of devices that can connect, access priorities, and which applications should be protected with specific KPIs for throughput, latency, and packet error rate. This level of reliability and control is critical for applications that require guaranteed connectivity and performance, such as IoT-enabled devices in a factory setting or warehouse facilities where always-on connectivity is a must.

Technology firms like private cellular because they have complete control of their network. RFPs from these types of business are showing the desire to move “all” functions to private cellular, including elements like video cameras, thermostats, people trackers, alarms, heating and cooling control, security systems, and a variety of sensors. Today’s technology isn’t ready to make this a complete reality, but understanding these requirements pushes the standards bodies, OEMs, carriers and hardware and software vendors to pay attention and develop solutions.

Entertainment Venues

One of the largest use cases for private networks is in entertainment venues, including sport stadiums, concert venues, amusement parks, etc.  A private network, specially P5G, would provide a more immersive experience to the spectator.  Another possibility is the transmission of events in 3D, in a way trying to provide an almost “in-person” experience, something that the metaverse (XR) is trying to accomplish. To date the actual deployments have been very limited as the killer applications require 5G, which still lacks the ecosystem depth found in 4G based networks.

Hospitals and Medical Campuses

The medical community is showing more and more interest in the PCN as it can provide always on, high reliability communications capabilities. In this application, traditional Wi-Fi networks will continue to exist (as the “regular” highway lane) while the PCN will be the specialized, faster highway lane (Comstock, 2021)

Several potential uses are commonly requested in RFPs:  1. Communication, with the desire to have reliable communication on the go; 2. Telehealth, where doctors may experience outages during a video conference with patients; typically, their device will be connected to the hospital’s Wi-Fi network, and that link can be compromised by interference and loading from other devices and services; 3. In-hospital retail for point-of-sale systems in hospital gift shops and cafeterias; even though these aren't clinical operations, long lines or delays caused by point-of-sale systems going down can negatively impact patient experience; 4. Augmented reality and virtual reality, an emerging application that uses AR and VR, especially in the surgical and clinical consulting space.  There are other applications, but these are the one most requested and discussed during the RFP process.

Industry 4.0:  Logistics and Manufacturing

Industry 4.0 is where most of the excitement exist today for PCNs. Industry 4.0 factories include IIoT devices like remote vehicles, robots, and automated equipment. All these devices need predictable wireless connectivity that can be supported with SLAs on latency and packet error rate and with constant coverage (Celona). In an industry where downtime is unacceptable, maintenance needs to be accurately predicted to ensure the factory activities are always working. Organizations like 5GACIA in Germany are creating ecosystems that will drive economies of scale for P5G based solutions. In their website they indicate that “5G-ACIA is the central global forum for shaping 5G in the industrial domain. On one platform, various industries from all over the world jointly create a new ICT and OT ecosystem and set the frameworks for a highly attractive emerging market”.  One of the key services for industry 4.0 relates to automated “robots”, with robots being a broad term that includes automated vehicles, assembly machines, etc.  Few manufacturers have experience designing and installing a mobile network and the variety of needed solutions makes it that no turnkey, plug-and-play P5G network solution is available. Even if there were, they'd still have to be extensively customized to ensure that everything functions as per the requirements.  In the end, PCNs will help meet the challenges with interference-free operation, higher reliability, predictable SLAs, and tighter security to keep the Industrial IoT infrastructure operating efficiently.

Mining

A mine is one of the earth’s most inhospitable environments – wet, dusty, with toxic gases, and surrounded by thick rock, and is an ideal candidate for PCNs. Safety is one of the main priorities in a mining operation, which includes heavy machinery operators and underground mining safety. Over the last few years, PLTE and now P5G networks have been deployed in mines across the globe, in most cases safety has been improved dramatically by merging reliable communication with automation and safety solutions. Heavy machinery can now be operated remotely from a control center and underground mines can be actively monitored for air quality, seismic activity, etc.  Efficiency can also be enhanced as vehicle automation allows for better planning and control of their movement in the mine site. Companies like Rio Tinto have implemented large scale PLTE across their mines for a decade, achieving increased safety and productivity (Daeuble).

Public Safety & Smart City

Perhaps the farthest away from realization of all the potential takers for private cellular are municipalities.  Although there are some very advanced activities in some large US cities (e.g., New York and San Francisco), the reality is that most municipalities in the US are still far away from embracing private cellular solutions. Even today, most municipalities still struggle to offer basic Wi-Fi access for green spaces as an example.  At the same time, municipalities are taking a much more proactive approach to public safety applications in part driven by the availability of grants for such projects. I have spent many days working on solutions for many municipalities, large and small, with very little follow through. Examples of successful undertakings include the city of Tucson, which has built a PLTE network tied to its public safety, education and transportation systems (link here). It is important to point out that municipalities are also able to join FirstNet as a way to provide an advanced network purposely built for first responders and public safety applications. FirstNet is a special case of a “private” public cellular network built specifically for this use case.

Summing Things Up

PCNs, when used in conjunction with traditional Wi-Fi/wired networks, give organizations complete control over their communications needs, enabling performance, coverage, and security to be customized to meet business requirements. Additionally, private cellular connections offer lower latency and more consistent service levels because the network is not subject to traffic spikes and throttling on the carrier’s network. Globally, spectrum is being allocated for private use, companies are rushing to provide solutions, and use cases are expanding daily.  Businesses adopting PLTE or P5G see this as a way to make their operations more efficient and future proof, that is why private networks are seen as a requirement, not a luxury. But many challenges remain: SAS systems need to be fully vetted, solutions have to prove that they indeed deliver the stated benefits (some are more mature than others) with platforms that can address the needs of a diverse set of verticals, IT organizations need to come up to speed to manage these more complex solutions, new non-traditional vendors are now part of the enterprises’ supply chain and a global ecosystem needs to develop in order to drive costs, this includes global allocation of spectrum for private use.  It’s nice to have more tools in the toolbox, especially in my day-to-day field of operation and that’s how I look at PCNs, as another tool in the toolkit.

References

  1. Celona. (n.d.). Private LTE Use Cases: Is It Right For Your Organization? Retrieved from www.celona.io: https://www.celona.io/cbrs/private-lte-use-cases-is-it-right-for-your-organization
  2. Comstock, J. (2021, august 23). 5 use cases for private 5G networks in hospitals. Retrieved from Healthcareitnews: https://www.healthcareitnews.com/
  3. Daeuble, S. (n.d.). The rise of private wireless explained. Retrieved from www.ft.com: https://www.ft.com/partnercontent/nokia-private-wireless/the-rise-of-private-wireless-explained.html

Statements and opinions given in a work published by the IEEE or the IEEE Communications Society are the expressions of the author(s). Responsibility for the content of published articles rests upon the authors(s), not IEEE nor the IEEE Communications Society.

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