> For the complete documentation index, see [llms.txt](https://docs.gxc.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.gxc.io/private-5g-spectrum.md).

# Private 5G Spectrum

A private cellular network needs spectrum, and unlike Wi-Fi, you do not simply switch it on. Every band Onyx supports carries its own licensing model, its own regulator, and its own set of obligations that continue for as long as the network operates.

This page covers what spectrum Onyx can use, how you get access to it in each region, and what the regulator expects of you afterwards. Read it before [*Step 1 — Capacity*](/plan-your-network/capacity.md): the band you can actually obtain constrains channel bandwidth, which constrains throughput, which sets the radio count.

## The three ways to get spectrum

Private cellular spectrum comes from one of three models. Which one applies to you depends entirely on where the site is.

<table><thead><tr><th width="200">Model</th><th>How access works</th><th>Where it applies</th></tr></thead><tbody><tr><td><strong>Shared / coordinated</strong></td><td>A central database authorises each radio dynamically and can modify or revoke that authorisation at any time. No auction, no licence fee.</td><td>CBRS in the United States (n48/B48)</td></tr><tr><td><strong>Local licensed</strong></td><td>The regulator issues a site- or area-specific licence directly to the enterprise, typically for a fixed term and a fixed fee.</td><td>n77/n78 in much of Europe and Asia-Pacific</td></tr><tr><td><strong>Operator-provided</strong></td><td>A mobile network operator leases capacity from its own licensed holdings for use on your private network.</td><td>Widely available; the usual route for FDD bands such as n26 and n28</td></tr></tbody></table>

{% hint style="warning" %}
**NOTE**: Spectrum availability is the single most common reason a design has to change late. Confirm which band you can actually obtain — and at what channel bandwidth — before committing to a capacity plan. A design sized for 100 MHz on n78 does not survive being moved to 20 MHz on CBRS.
{% endhint %}

## Bands supported by Onyx

### 5G NR

<table><thead><tr><th width="110">Band</th><th width="90">Duplex</th><th width="230">Frequency</th><th>Access Points</th></tr></thead><tbody><tr><td><strong>n48</strong> (CBRS)</td><td>TDD</td><td>3550–3700 MHz</td><td>G105 (indoor), G505 (outdoor)</td></tr><tr><td><strong>n78</strong></td><td>TDD</td><td>3300–3800 MHz</td><td>G105 (indoor), G505 · G506 (outdoor)</td></tr><tr><td><strong>n77</strong></td><td>TDD</td><td>3800–4200 MHz (G506)<br>3700–4200 MHz (G105, future release)</td><td>G506 (outdoor), G105 (indoor, future release)</td></tr><tr><td><strong>n41</strong></td><td>TDD</td><td>2496–2690 MHz</td><td>G509-n41 (outdoor)</td></tr><tr><td><strong>n79</strong></td><td>TDD</td><td>4700–5000 MHz</td><td>G509-n79 (outdoor)</td></tr><tr><td><strong>n28</strong></td><td>FDD</td><td>UL 703–748 MHz · DL 758–803 MHz</td><td>G509-n28 (outdoor)</td></tr><tr><td><strong>n26</strong></td><td>FDD</td><td>UL 814–849 MHz · DL 859–894 MHz</td><td>G509-n26 (outdoor)</td></tr></tbody></table>

### LTE

<table><thead><tr><th width="110">Band</th><th width="90">Duplex</th><th width="230">Frequency</th><th>Access Points</th></tr></thead><tbody><tr><td><strong>B48</strong> (CBRS)</td><td>TDD</td><td>3550–3700 MHz</td><td>G100 (indoor), G101 · G501 (outdoor)</td></tr><tr><td><strong>B3</strong></td><td>FDD</td><td>UL 1710–1785 MHz · DL 1805–1880 MHz</td><td>G229 (indoor)</td></tr><tr><td><strong>B1</strong></td><td>FDD</td><td>UL 1920–1980 MHz · DL 2110–2170 MHz</td><td>G249 (outdoor)</td></tr></tbody></table>

For transmit power, MIMO configuration, channel bandwidth options, and link budget per model, see the individual specification sheets under [*Onyx Hardware*](https://docs.gxc.io/hw/onyx-hardware/gxc-5g-and-lte-hardware).

## What the band choice determines

Band selection is not only a licensing question. It propagates through the whole design.

**Duplex mode sets the uplink ceiling.** The TDD bands — n48, n77, n78, n41, n79 — share one channel between uplink and downlink on a configurable slot pattern, so uplink capacity is a design decision. Onyx supports patterns from 77% DL / 21% UL (`DDDDDDDSUU`) through to 34% DL / 63% UL (`DSUUU`). The FDD bands — n26, n28, B1, B3 — give uplink and downlink permanently separate channels, so the split is fixed but guaranteed.

**Frequency sets the coverage radius.** The sub-GHz FDD bands (n28 at 703–803 MHz, n26 at 814–894 MHz) propagate substantially further and penetrate structure better than the mid-band TDD options at 3.3–5.0 GHz. Their channel bandwidths are correspondingly narrow — 40 MHz on n28, 20 MHz on n26, against up to 100 MHz on n78. Coverage and capacity pull in opposite directions here.

**Channel bandwidth sets the throughput.** This is the number that carries into [*Step 1 - Capacity*](/plan-your-network/capacity.md). CBRS grants in particular are frequently narrower than the maximum the hardware supports, because the SAS issues what is available rather than what you request.

{% hint style="warning" %}
**NOTE**: Every cell sharing a band at a site — and any neighbouring operator in the same band — must use the same TDD pattern and frame timing. The slot pattern is a site-wide decision, not a per-application one. Where two applications need incompatible splits, separate them onto different carriers rather than compromising both.
{% endhint %}

## CBRS in the United States

CBRS is the most common route to private cellular spectrum in the US, and the one with the most operational obligation attached. It operates in 3550–3700 MHz under *47 CFR Part 96*, regulated by the FCC.

### The three-tier model

Access is prioritised across three tiers, and the Spectrum Access System (SAS) enforces that priority continuously.

| Tier                                         | Users                                                                                   | Protection                                                                    |
| -------------------------------------------- | --------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------- |
| **Tier 1 — Incumbents**                      | US Navy radar, Fixed Satellite Service earth stations, other federally authorised users | Full protection. When incumbent activity is detected, all lower tiers vacate. |
| **Tier 2 — Priority Access Licence (PAL)**   | Licensees holding exclusive rights won at FCC auction                                   | Protected within the licensed geographic area; yields to incumbents.          |
| **Tier 3 — General Authorized Access (GAA)** | Licence-by-rule, open to anyone                                                         | Shared, non-exclusive, no interference protection.                            |

Most private deployments, including most GXC Onyx deployments, run on **GAA**. There is no licence to buy and no auction to enter — but there is also no protection, and a grant can be modified or withdrawn.

### What this obligates you to

CBRS is not permission granted once. It is authorisation maintained continuously.

* **Every radio must register with an FCC-approved SAS before it transmits.** Onyx handles this through an integrated Domain Proxy, so registration and grant management happen from the Onyx Portal rather than radio by radio. GXC's primary SAS provider is Federated Wireless, though the platform is designed to work with any FCC-approved SAS.
* **A Certified Professional Installer must certify each installation.** The FCC requires a credentialed CPI to verify and digitally sign the installation parameters — location, antenna height AGL, azimuth, downtilt, gain, and deployment category — before those records go to the SAS. CPI certification is issued to an individual, not a company, and that individual is accountable for the accuracy of every record they sign.
* **Grants must be maintained by heartbeat.** Each radio sends periodic heartbeats through the Domain Proxy. Miss the interval, or have spectrum availability change, and the SAS may suspend, modify, or terminate the grant.
* **The SAS can reconfigure your network without warning.** Environmental Sensing Capability sensors watch for federal incumbent activity. When a Dynamic Protection Area activates, the SAS automatically reassigns frequencies, reduces transmit power, or suspends transmission until the incumbent clears. Onyx handles this automatically — but plan for a network whose operating frequency and bandwidth can change during normal operation.

{% hint style="info" %}
**NOTE**: Plan your capacity against the bandwidth you are likely to be *granted*, not the maximum the band allows. A GAA deployment that only works at its peak grant is a deployment that stops working when a higher tier needs the spectrum.
{% endhint %}

For the complete registration workflow — CPI account setup, deployment creation, CBSD records, signing, Onyx Portal configuration, grant verification, and troubleshooting — see [*4G & 5G Onyx CBRS SAS Registration*](https://docs.gxc.io/docs/application-notes/4g-and-5g-onyx-cbrs-sas-registration).

## Outside the United States

Local licensing for private networks is now established in many markets, most commonly in n77 and n78. Terms vary widely — some regulators issue per-site licences on application, others allocate regional blocks, and some route private allocations through incumbent operators.

Two things are consistent enough to plan around:

* **Mid-band TDD (n77/n78) is the mainstream private allocation.** If a market has a dedicated private-network band, it is usually here.
* **Equipment authorisation is separate from spectrum authorisation.** Holding a licence does not by itself permit you to deploy a given radio. Each Onyx AP ships with regulatory compliance information for its supported markets; see the *Appendix — Regulatory Compliance* in that model's hardware installation guide.

{% hint style="info" %}
**NOTE**: Regulatory frameworks for private spectrum change faster than most documentation. Confirm current terms with the national regulator, and contact GXC before finalising a design that depends on a specific allocation.
{% endhint %}

## Compliance and certification

* **FCC Part 96** — Onyx is FCC-certified for Part 96 compliance, supporting shared CBRS spectrum use in the United States.
* **Integrated CBRS Domain Proxy** — enables compliant, interference-free shared-spectrum operation through encrypted communication with the SAS.
* **Per-model regulatory compliance** — each AP, mesh node, and FHM hardware installation guide includes a regulatory compliance appendix covering the markets that model is approved for.

For the platform's wider security posture and certifications, see [*Security and Compliance*](/security-and-compliance.md).

## Related reading

* [*4G & 5G Onyx CBRS SAS Registration*](https://docs.gxc.io/application-notes/4g-and-5g-onyx-cbrs-sas-registration) — the full CBSD registration workflow, end to end
* [*Step 1 — Capacity*](/plan-your-network/capacity.md) — how channel bandwidth and TDD pattern turn into a radio count
* [*Onyx Hardware*](https://docs.gxc.io/hw/onyx-hardware/gxc-5g-and-lte-hardware) — per-model frequency, power, and regulatory detail
  * [*Glossary*](/glossary.md) — CBRS, SAS, CBSD, CPI, GAA, PAL, DPA, and related terms

## Contact GXC

To get in touch with GXC, please visit <https://gxc.io/contact-us/>.


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