Industries of every kind are embracing automation and digitalization as part of Industry 4.0. Connecting thousands of IoT sensors, autonomous vehicles and machines, and connecting workers to AI-driven analytics requires robust private wireless networks. And by robust, I mean something more than just Wi-Fi. Cellular technologies, 4.9G/LTE and 5G, have the technical capability and robustness, but the radio spectrum they use has up to now been licensed and sometimes expensive to access. That is, until CBRS.

CBRS or Citizen Broadband Radio Spectrum is the result of a joint effort in the US between the FCC and industry to share existing radio spectrum - historically used by the US navy for radar on the coasts, satellite comms and some fixed wireless providers - and make it available for private use, some of it requiring licensing (called Priority Access Licenses or PAL) for wider areas, and some of it not (called General Authorized Access or GAA).

CBRS mainstream deployments starting in the US

In late 2020, the FCC announced the results of the CBRS auction of spectrum to the priority access licenses (PAL) users. The FCC’s CBRS PAL auction is like the starting gun going off for spectrum sharing. And together with the GAA availability in early 2020, these were the shots that have been heard around the world. Although CBRS only applies to the US, other countries are watching with interest to see how this spectrum sharing experiment will turn out – and so far, it is pretty good. The FCC raised $4.5 billion in the auction, awarding PAL licenses to 271 companies. The question everyone is wanting an answer to is how will the sharing scheme work in practice?

The scheme that was developed by the FCC and the CBRS alliance was to designate three user tiers. The incumbent users were the highest priority tier. A second licensed tier were the PAL license holders, now awarded to 271 companies in the recent auction. The third tier, General Authorized Access (GAA) is available to any private users. Most enterprise or industrial users will be in the GAA designation, although some PAL licenses have also been picked up by some enterprises, in segments like utilities, where the need for private wireless goes beyond industrial sites. Some companies have also picked up PAL licenses in order to offer critical connectivity services to enterprises in their licensed geographical areas.

For the GAA users, sharing this valuable slice of radio spectrum unleashes the opportunity to accelerate and intensify their Industry 4.0 goals. As we’ve seen in countries that released vertical spectrum, free, or low cost, vertical spectrum lowers the bar to entry and enables enterprises to use 4.9G/LTE and 5G private wireless with its ultra-low latency and high bandwidth performance for both fixed and mobile applications.

For CSPs, access to this low-TCO spectrum enables them to expand their coverage and provide lower cost private wireless services — also to enterprise customers. For MSOs, it opens up the possibility of providing wireless enterprise services as well. Overall, the market for CSPs and MSOs in the CBRS space is expected to amount to an investment in radio access networks of more than $2B by 2024 according to Dell’Oro Group.

This sharing approach requires the implementation of a specific architecture and specific network systems. The shared use of the spectrum requires the CBRS access points (so called CBRS Devices or CBSDs) to connect to a Spectrum Access System (SAS), which manages the users’ priorities and grant access to the spectrum to avoid interference with other CBSDs. If placed in incumbent areas, the system should also rely on an Environmental Sensing Capabilities (ESC) system, which monitors the use of the spectrum by the naval incumbent and informs the Spectrum Access System (SAS).  

Integrated SAS CBRS solution speeds delivery

The one downside of CBRS is the complexity of implementation because enterprises must deal with multiple players for equipment, SAS and ESC capabilities. As the market leader in private wireless, we are excited to partner with KeyBridge in providing the sole integrated CBRS solution for CSPs, MSOs and our enterprise customers. KeyBridge brings their certified SAS and ESC, and we bring the private wireless solutions, either 4.9G/LTE or 5G, including CBRS end points, CBRS certified radio, backhaul/transport, core and applications.

The Nokia-KeyBridge integrated approach to CBRS not only facilitates integration efforts, as everything is pre-tested and comes from a single vendor, but it also allows us to optimize the solution in important ways that provide greater reliability.

Mission-critical CBRS service reliability - beyond FCC requirements

For enterprise customers that are leveraging CBRS for Industry 4.0, reliability is critical. To avoid any CBRS service interruptions for low priority users, Nokia has also implemented a set of Nokia Bell Labs innovations that go beyond the baseline FCC requirements. The first one is a smart distributed SAS geo-redundancy mechanism that forms part of the KeyBridge SAS solution and offers a seamless connection to a secondary SAS in case the connection is lost to the primary SAS.

The other is the implementation of Nokia Domain Proxy for even greater reliability. Implemented at the edge cloud, the Nokia Domain Proxy aggregates multiple CSBD links to the SAS, which brings high operational benefit for big private wireless network deployments. It also doubles redundancy to ensure that users maintain their spectrum grant, even in the rare case where access to the primary and secondary SAS is interrupted. The end result is extreme reliability to support business and mission-critical communications.

As the world watches the launch of CBRS, we are confident that the shared spectrum model will prove to be a big success. We believe that the Nokia-KeyBridge approach and Nokia innovations will add to the successful uptake of CBRS in the US by offering a more reliable and easier to implement private wireless service. In the long term, this will convince other countries around the world to develop shared spectrum approaches of their own. All of which is good news for enterprises and industries, as well as CSPs and MSOs worldwide.