LTE and 5G private networks are not yet plug-and-play. They still need the engineering touch to solve business problems, said Cradlepoint’s Todd Krautkremer and Donna Johnson.

5G may, in the long run, prove more beneficial to business and industry than to consumers. Private networks, whether 5G or LTE, let organizations connect devices within factories, ports, campuses, exhibit halls, or other locations.

What do you need to set up a private cellular network? It’s more difficult that using Wi-Fi, at least for now. Should devices connect directly to the network or connect to a router or gateway to the cellular network? Cradlepoint now part of Ericsson, provides cellular routers that connect to private networks. 5G Technology World spoke with Todd Krautkremer, CMO, and Donna Johnson, VP of Product and Solution Marketing about what you need to develop a private network and how to connect your devices.

5GTW: What’s the status of private networks today?
Krautkremer: We are seeing private use cases and an $8B market opportunity by 2024/2025. Citizens Broadcast Radio Service (CBRS) technology in the U.S. has made spectrum easy to get for private networks. In other parts of the world, you must make special arrangements with carriers or governments to obtain spectrum. In the US, CBRS is well structured and works reasonably well in practice. Large sites with large numbers of connections have exceeded the capabilities of Wi-Fi.

Schools are looking towards private network because they serve students who may live several miles away. Underprivileged and under-connected families need broadband access to get distance learning, and private networks can help. Sadly, the broadband connectivity problem isn’t going away anytime soon given the resurgence of COVID.

We see private networks as possibly operating in smart cities, where the challenge is the large number of endpoints that need to connect to networks. Part of that is because of security. Making those connections with other technologies is expensive and difficult to maintain.

Getting access to spectrum through the CBRS makes private cellular networks viable. We expect that market to grow over the next three to four years. The technical goal is to make connectivity through cellular or Wi-Fi 6 easily deployable. 5G must become as deployable as Wi-Fi. I expect private cellular networks to take off over the next three-to-five years.

5GTW: What do you need to use CBRS in a private network?
Johnson: For CBRS (3550 MHz to 3700 MHz), you need a Citizens Broadband Service Device (CBSD), which must be registered in a database so that the cloud-based Spectrum Access System (SAS) can manage channel access. The CBRS frequencies are shared with the U.S. Navy, which gets priority over other users when it needs the airwaves.

Krautkremer: CBRS in the U.S. and other cellular networks throughout the world have specific frequencies. Not every modem, even LTE modems, will support every frequency. When you build a private network that uses CRBS, the modems you choose must support the frequencies you’re going to use. Having a legacy sensor that supports 4G connectivity doesn’t guarantee that it with work on the CBRS spectrum or on the frequency that’s available, which depends on your country.

5GTW: In addition to RF issues, what do engineers need to know about developing private cellular networks?
Krautkremer: For engineers, private networks are currently like a Tinkertoy in the sense that you get different parts from different vendors. You get your enhanced packet core (EPC) from one vendor, your user equipment from another vendor, and management software from another, then try to put it all together to solve a business problem. Companies are motivated to do that now. We know from previous technologies that consolidation takes place and eventually, you can get the network components from a single vendor. We see that coming. Right now, it takes a lot of engineering expertise to assemble a private network.

Johnson: Engineers love private networks. They can still pull pieces together and have a lot of control over how to configure the network. There’s a lot of tweaking that you can do right now regarding frequencies, locations, antenna optimization, and so on. It’s not a turnkey project. There’s plenty of room for customization. If you have the skills, you can create a highly optimized network to fit your use case. Over time, we’ll see this become a little more plug-and-play, much in the way that Wi-Fi networks work today.

When building a private network, you must start by knowing which frequency you’ll use. CBRS is a well-known frequency in the U.S. (Ed note: The Deutsche Messe exhibition site in Hannover, Germany will use a private network that operates between 3.7 GHz and 3.8 GHz.) Telecom carriers can allocate some of their licensed spectrum to private networks within a local area.

Krautkremer: We’re doing that now with a carrier in Canada.

5GTW: What about the digital aspects of private networks?
Johnson: Think inward from the network edge. Start with “what are you going to connect to the network?” If you use a router at the network edge, then you can connect devices over Wi-Fi, Ethernet, Bluetooth and even serial cables. The router then connects to the private network over the cellular connection. Alternatively, you can also connect individual devices to a private network. For that, each device needs a SIM that lets devices connect to a specific network. You may need a connection to the internet because your data could exit the private network.

5GTW: What are the ways the devices can connect to private networks?
Johnson: Devices can connect to a router, or they can connect directly to the private network.

Krautkremer: Devices need a private network SIM.

Johnson: When going through a router or gateway, IoT devices don’t need to know that they’re on a private network. They can connect using Bluetooth, Wi-Fi, Ethernet, or even a serial cable. For vehicles, devices might use an OBD2 connection to get vehicle information. Think of these connections as a LAN within a LAN. Not every device needs direct connectivity to the private network. A router or gateway eliminates the need for every device to use a SIM.

5GTW: Can organizations use a combination of public and private networks?
Johnson: Yes. School districts, for example, might use a private network, but they decide which information should be available on the internet.

One of the early use cases for private 5G networks is in sporting arenas. A private network could be used to broadcast HD video throughout the arena. In that instance, a carrier might allow use of its spectrum for a private network, but within a confined area.

Krautkremer: The private network might connect to small cells that provide users with connectivity. Users can use their existing SIM to gain access to the private network through their public network connection. AT&T recently announced such a 5G network in Seattle.

Johnson: We also see applications in factories, ports, and other facilities. If you have the technical knowledge, you’ll find that using a private network will be more cost effective than using a public network. Carriers encourage the use of private networks because they relieve the public network of some connections. Too many people trying to stream 4k video in a stadium may, for example, cause others users to lose connectivity.