CBRS
Citizens Broadband Radio Service: US 3.5 GHz shared spectrum band with three-tier hierarchy (Incumbent, PAL, GAA) managed by SAS.
CBRS is the US framework that opened up 3.5 GHz (3550–3700 MHz) for shared use, and it's the reason private 4G/5G took off faster in the States than in markets where you'd have to buy licensed spectrum outright. The clever part is the three-tier hierarchy that lets very different users coexist in the same band:
- Incumbents — the original occupants (notably US Navy radar and some satellite earth stations) get absolute top priority and must be protected.
- PAL — Priority Access Licences, auctioned to operators for protected, exclusive use in a county, sitting below incumbents.
- GAA — General Authorized Access, the free, licence-exempt tier anyone can use opportunistically, protected from no one.
Holding it all together is the SAS, an automated coordinator that hands out and reclaims channels in real time so nobody steps on a higher tier. For an enterprise, the appeal is the GAA tier: usable spectrum with no auction and no operator, which is why so much private 5G in the US runs on CBRS.
Frequently asked questions
- Do I need a licence to use CBRS?
- Not for the GAA tier — General Authorized Access is licence-exempt, which is why enterprises can stand up private networks on CBRS without an auction. Your devices and the operator must register with a SAS, but there's no spectrum fee. If you want protected, interference-managed spectrum you bid for a PAL (Priority Access Licence). Either way the SAS coordinates everything so you don't interfere with incumbents or higher tiers.
Related terms
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