As policymakers consider how to squeeze more spectrum from an already crowded landscape, inventive and innovative solutions can enable more efficient use of the finite amount available. One such solution lies in the band of spectrum known as Citizens Broadband Radio Service, or CBRS.
- CBRS is a pioneering spectrum-sharing regime established in the 3.55 GHz to 3.7 GHz spectrum band, which was previously primarily used by the Department of Defense (DoD).
- After years of analysis by the executive branch, the FCC, and other stakeholders, the FCC opened the band to commercial wireless use via shared-licensing, which allowed the DoD to continue its operations.
- As a result, the CBRS band has become a case study for how sharing can be implemented successfully.
NCTA interviewed CableLabs’ Mark Poletti, Senior Director of Wireless Mobile Networks, to get an expert’s insight into this innovative band and what the band’s success could mean for future spectrum solutions.
What have been the benefits of CBRS?
The main benefit of CBRS is that it effectively shares spectrum between licensed, licensed by rule and incumbent users.
- It’s an innovative alternative way to keep incumbents from being moved while allowing new users to use and share the band.
- It also efficiently uses the spectrum when licensed users aren’t using it. For example, General Authorized Access (GAA) users can use Priority Access License (PAL) channels when PAL users aren’t using them. This provides economic incentives to operators to have access to the entire 150 MHz of spectrum without having to pay for licensed spectrum.
- In-building private networks are an example of places where the PAL channels may not be in use – such as factories, warehouses, campuses, etc. – where an operator can get access to the full band without having a license.
- This allows for the accessibility of the entire band to be more fully utilized compared to a traditional licensed band, which can only be used by the license owner.
The other benefit is that the Spectrum Access System (SAS) provides centralized spectrum management, so it protects the incumbents from interference from coexisting users and also protects interference from PAL users.
- This centralized management system has proven to be an effective way to share the spectrum efficiently.
How has it been successfully deployed?
CBRS’ success is exemplified by the numbers:
- Over 400,000 4G and 5G Citizens Broadband Radio Service Devices (CBSD) are deployed.
- 17,000 PAL licenses are issued.
- 350+ FCC-approved 4G and 5G CBSDs are in use.
What does the success of CBRS say about other bands that could be reclassified for shared use?
The success of CBRS is a very good baseline for which other bands can build upon, particularly as policymakers assess how to enable more federal and commercial spectrum sharing.
