For decades, many utility companies around the world owned private cellular networks to support internal applications such as remote meter reading. Today, private networks are an increasingly popular choice for myriad additional types of organizations, including manufacturers, logistics companies, sports venues, municipalities, and universities.
Then and now, the primary reason is that ownership gives organizations far more control over coverage, cybersecurity, traffic prioritization, and quality of service (QoS) than if they were just another customer of a public network. Another common reason is that private cellular networks offer more flexibility and capabilities than the legacy Wi-Fi and/or copper networks that they replace.
For example, many manufacturers traditionally used Wi-Fi for connecting fixed and mobile IoT devices around the factory floor. But in a 2021 Analysys Mason survey, 76% of manufacturers said they plan to switch to private 5G because it provides greater security and reliability than Wi-Fi.
Network Architecture and Implementation Options
Businesses typically own and operate their Wi-Fi LANs, so it’s helpful to use those to understand the major components of a private cellular network:
- The radio access network (RAN) in a cellular network consists of the cell sites, also known as base stations. Cell sites are akin to access points in a Wi-Fi network.
- The core network consists of nodes such as packet gateways that connect the RAN to the internet and to other mobile networks. These nodes are like the switches and routers in a Wi-Fi network.
There are three options for implementing a private cellular network:
- Build and operate both the core network and RAN, just like a public wireless carrier, but on a much smaller geographic scale.
- Lease a virtual, private slice of a mobile operator’s public 4G or 5G network. The business gets exclusive access to this slice, so its data doesn’t mix with traffic from the operator’s other customers. This eliminates the expense and expertise of building and operating a network while still providing autonomy and control.
- A hybrid, where the business owns the network at its facilities but uses a private slice of a public network elsewhere. An example is a logistics provider whose trucks, trailers, and shipping containers use its private network at its warehouses and ports. When those assets leave those facilities, they switch to the private slice of the public network.
A Spectrum of Choices
One reason why so many businesses have Wi-Fi networks is because the spectrum is free. The big drawback is that everyone else can use that unlicensed spectrum, so their Wi-Fi traffic is competing for scarce frequencies with other nearby users.
Private cellular networks use licensed spectrum, just like mobile operators, which each pay between nine and 11 figures for that right. But in many countries, enterprises, schools, and other qualified organizations can get licensed spectrum for free or at a relatively low cost. For example, in the U.S., private cellular networks have free access to the Citizens Broadband Radio Service (CBRS) band. (For a deeper dive, see https://www.ericsson.com/en/small-cells/cbrs)
The CBRS band is at 3.5 GHz, which is noteworthy because it highlights another implementation consideration: choosing the right band for a particular use case. One rule of thumb is that the higher the frequency, the more bandwidth it can support. Another rule of thumb is that signals don’t travel as far at higher frequencies than they do at lower ones. As a result, a private network that uses a higher band like CBRS will need more base stations, which is an additional cost.
For example, 700 MHz is a good fit for private networks that need to cover a large outdoor area, such as a port or campus. The CBRS band is a good fit for small-scale and/or indoor applications, such as a factory.
4G, 5G, or 6G?
Spectrum also is a factor when choosing which cellular generation to use. For example, 5G standards support far more bands than 4G, such as the millimeter wave (mmWave) spectrum that provide gigabit speeds. (For a deeper dive, see “4G vs. LTE vs. 5G: How Mobile Technology is Evolving” and “Enhancing Connectivity: The Role of Multi-Band Cellular Antennas in Expanding Network Coverage.”)
Device costs, latency, and standards roadmaps are additional considerations when choosing between 4G and 5G. (For a deeper dive, see “Going the Distance: LTE 450 Enables Long-Range Mission-Critical Communications for the Long Haul” and “Choosing Between 4G LTE and 5G: What Network Evolution Means for Industrial Connectivity.”)
6G network infrastructure and devices probably won’t start to become commercially available until 2030. They’ll also carry a hefty price premium simply because the technology hasn’t had time to start descending the cost curve.
Even so, preliminary standards work suggests that private 6G will be a good fit for many business applications, such as Industry 4.0 automation. That means it’s worth following now to keep up with its development to see where it fits into long-range plans. (For more information, see “What Is 6G? All You Need to Know About 6G Technology” and “Potential Applications of 6G in Industrial Automation and Smart Factories.”)
