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CBRS (US, FCC Part 96)

Fairwave defaults to lab/no-RF mode. Transmitting on cellular bands without proper authorization is illegal in most jurisdictions. You are solely responsible for licenses, SAS grants, indoor restrictions, and type approval. HyperonX and contributors provide software as-is for lawful private networks, research, and shared-spectrum regimes only.

CBRS is the one US path where a community network can operate lawfully and unencumbered on 3.5 GHz - provided the hardware and software chain is certified and SAS-connected.

FCC Part 96 Basics

  • 3.5 GHz band (3550–3700 MHz) shared with incumbent federal users and Priority Access Licensees (PAL).
  • GAA (General Authorized Access) - unlicensed-by-individual authorization obtained via SAS; no auction, but must register with a SAS and receive grants.
  • PPA (PAL Protection Area) - protection arrangements for PAL holders.
  • Certified CBSD - every Citizens Broadband Radio Service Device must be certified by the FCC and registered with an approved SAS.
  • EIRP caps: GAA ≤ 30 dBm / 10 MHz nominal (with exceptions); PAL higher. The SAS grant, not the cap, is the binding constraint at runtime.
  • GPS required - Part 96 mandates location integrity; a GPS/GNSS reference (PPS) is part of the CBSD requirement.

SAS Providers

The FCC approves SAS instances; among the commercial providers historically: CommScope (Sony is a co-sponsor), Federated Wireless, Google, and others approved at any given time. The current approved list lives with the FCC. Fairwave ships no SAS client of its own in v0.1 - the requirement is to use a certified SAS client (either the CBSD vendor's or a third-party approved one).

Why a Certified SAS Client Is Required

  1. A grant from a non-approved SAS is not a grant at all - it is interference.
  2. Fairwave's own mock SAS (cbrs/mocksas) is for development and CI only: it grants instantly, checks nothing, and has no regulatory standing. It must never be used to clear a deployment to transmit.
  3. Grants, heartbeats, and shutdown commands come from the real SAS; Fairwave's tx/arm policy should require sas_grant_ref before arming the cbrs profile.

CBSD Radio Path

A certified small-cell radio path is mandatory (Part 96 certification on the device). A generic USB SDR is not a CBSD and cannot be gated into CBRS legality by software. See docs/hardware/bom-tiers.md for the certified-path BOM.

flowchart LR
    CBSD["Certified CBSD radio"] -->|SAS protocol| SAS["Approved SAS"]
    SAS -->|grant + heartbeat| CBSD
    CTRL["fairwave-control"] -->|policy: sas_grant_ref| CBSD
    CBSD --> RAN["srsRAN eNB (band 48/ n48)"]

Mock SAS Stub

  • mocksas exists so CI can test gate logic without a network connection.
  • It logs everything it "grants" - treat that as an audit artifact, not a licence.
  • Deploy gate: fairwave policy set --profile cbrs --sas-endpoint <approved>; the mock endpoint should be rejected by policy in a production profile.

Deploy Checklist (CBRS)

  1. Confirm the radio path carries a Part 96 certification (device model registered).
  2. Register the CBSD with an approved SAS; obtain SAS client credentials/cert.
  3. Install GPS reference; verify PPS lock before startup.
  4. Configure fairwave policy profile cbrs: band 48, EIRP cap per grant class, sas_endpoint = approved SAS, sas_grant_ref required.
  5. Start stack; confirm SAS heartbeat and grant before any TX.
  6. Set tx/arm with the grant reference; verify agent safe_tx.
  7. Log grants and heartbeats; keep them (audit/evidence).
  • Regional table: docs/spectrum-and-law/regional.md
  • BOM: docs/hardware/bom-tiers.md
  • Checklist: docs/spectrum-and-law/compliance-checklist.md