Last week, the FCC approved five companies to begin initial commercial deployments of the Citizens Broadband Radio Service (CBRS), which introduces a flexible model for spectrum sharing in the 3.5GHz band.

This development represents a major milestone in what has been a huge talking point in the US over the last few years. Nevertheless, CBRS is not widely understood elsewhere even though its implications are potentially wide-reaching. This makes it important to explore what CBRS means for mobile operators, as well as those companies outside of the industry, which will use CBRS as a testbed for deploying their own connectivity solutions.

How does CBRS work?
The CBRS initiative opens up 150MHz of the 3.5GHz band (3550MHz to 3700MHz) using a three-tiered approach to spectrum management:

  • Incumbents: Includes military, satellite providers and wireless ISPs. These users have the most rights over the CBRS spectrum.
  • Priority Access Licences (PAL): Holders pay to buy rights to a portion of the spectrum (70MHz), but can only use the spectrum when it is not in use by incumbents. The PAL spectrum auction takes place in 2020 using county-sized licence areas.
  • General Authorised Access (GAA): Users will be allowed localised access to up to 80MHz of spectrum as long as it does not interfere with incumbents or PAL holders. GAA spectrum will be made immediately available for commercial deployments.

The five companies approved by the FCC to start commercial deployments (Amdocs, CommScope, Federated Wireless, Google and Sony) are Spectrum Access System (SAS) administrators. Their role is to manage requests to use the spectrum at particular times and in certain areas, ensuring there is no interference between the three tiers.

How does CBRS benefit mobile operators?
In GSMA Intelligence’s report Region in Focus: North America (released this week), we look at the latest telecoms and broader TMT trends in the region, including a detailed look at CBRS’s potential impact on mobile operators. One key benefit will be the chance for operators to use CBRS spectrum to boost mobile capacity in congested locations. This is similar to how some operators deployed the unlicensed 5GHz band via Licensed Assisted Access (LAA).

Mobile operators seeking to enhance capacity will benefit from 3.5GHz spectrum emerging globally as a key 5G licence band. This means we can expect to see a steady release of new smartphones compatible with CBRS, including the latest iPhones and Samsung Galaxy devices.

Yet, CBRS’s potential extends beyond smartphones. It presents mobile operators with a chance to deliver home broadband services through fixed wireless access (FWA) technology. These deployments can be expected as early as this year, with AT&T already working with Samsung and CommScope to rollout FWA services using CBRS spectrum.

New opportunities, new players
CBRS will also drive change in other areas. For example, the use of localised spectrum licences makes it easier to deploy a location-specific mobile network, which allocates a dedicated slice of bandwidth for the sole use of a specific customer.

Demand for location-specific networks is likely to come from several enterprise verticals such as the manufacturing sector, which could use CBRS to support the high-speed mobility required by robots and vehicles as part of factory automation. There is also likely to be interest from industries involved in handling sensitive and personal data, attracted by the increased security offered by isolating their data from public networks.

CBRS also enables other solutions, such as neutral host networks. These are most common as localised deployments in busy places requiring ultra-high bandwidth (for example airports, shopping centres and stadiums). Several companies are trialling neutral host solutions including Wi-Fi hotspot operators (for example Boingo), equipment vendors and other localised network providers (Dense Air). CBRS allows neutral host networks to be deployed without mobile operators sharing licensed spectrum, easing commercial and technical obstacles.

Mobile operators are most likely to lead initial CBRS deployments. At the same time, operators can’t assume to be the default providers of connectivity. CBRS lowers the cost of entry to new providers, and many enterprises are taking this opportunity to experiment with deploying their own solutions. For example, Amazon plans to deploy CBRS at its Sunnyvale campus in California, building on a demo at AWS re:Invent 2018 where it showcased real-time surveillance cameras and smart meters.

What to expect next?
The initial commercial deployments of CBRS must run for a minimum of 30 consecutive days. SAS administrators will then report their findings to the FCC, ensuring their systems worked to prevent interference between users. After this, we will be closely watching out for further CBRS deployments as well as other key milestones, including:

  • PAL auction: PALs come with longer licence terms, larger coverage areas and greater rights than the GAA tier. However, the cost of acquiring PALs is likely to reflect these benefits. As such, the PAL auction will be a true barometer of demand for spectrum from those companies outside the mobile industry, which are deploying CBRS solutions in the GAA tier.
  • CBRS in 5G: CBRS will initially use LTE, with support for 5G coming later in the CBRS roadmap. This poses a dilemma to companies interested in deploying CBRS: move early on LTE or wait for 5G support? Many customers began planning their deployments when 5G was still a way off (reflecting the significant delays encountered by CBRS). It is therefore unlikely they will wait until CBRS supports 5G to commence deployments. This underlines the strong early demand seen by SAS administrators (such as Federated Wireless), which indicates LTE meets the initial CBRS requirements of most customers.
  • More spectrum sharing initiatives: If successful, CBRS could lead the FCC to pursue similar initiatives in other frequency bands. There will also be implications beyond the US, with many countries contemplating the merits of spectrum sharing initiatives. Some of these have already come to fruition, albeit in different forms to the three-tiered approach of CBRS. UK regulator Ofcom is enabling spectrum sharing through Shared Access and Local Access licences across four bands, while Germany’s Bundesnetzagentur has a gone a step further through reserving 100MHz of mid-band spectrum for local use.

James Joiner – analyst, Core Mobility Research – GSMA Intelligence

The editorial views expressed in this article are solely those of the author and will not necessarily reflect the views of the GSMA, its Members or Associate Members.