CBRS Band
Understanding CBRS Band
Frequency Spectrum and Channelization
The CBRS band occupies 150 MHz of spectrum spanning from 3550 MHz to 3700 MHz. In 3GPP standards, this frequency range is designated as Band 48 (for 4G LTE) and Band n48 (for 5G NR). The band sits in the mid-band range, which is highly valued for modern cellular networks because it offers a balance between the broad coverage of low-band spectrum (below 1 GHz) and the high data capacity of millimeter-wave spectrum.
The CBRS band is channelized into fifteen 10 MHz wide channels. To support high-capacity applications like video streaming and industrial IoT, CBRS hardware supports Carrier Aggregation (CA) and Channel Bonding, allowing a single connection to aggregate up to four 10 MHz channels (40 MHz total bandwidth) or more, depending on SAS availability. PAL licenses are limited to a maximum of 70 MHz of the band, leaving at least 80 MHz available for GAA usage in any given location.
RF Coexistence and Out-of-Band Emissions
Because the CBRS band is shared with government radar systems and commercial satellite downlinks, RF equipment operating in this band must comply with strict emission limits. Out-of-Band Emission (OOBE) limits are set by the FCC to prevent adjacent-channel interference. CBSDs must suppress power outside their allocated channel to prevent bleed-over into neighboring operations. In particular, the upper edge of the band (3700 MHz) borders the C-band satellite receive band, requiring strict filters on outdoor CBRS antennas.
Key Mathematical Relations
Technical Specifications Comparison
| Spectrum Block (MHz) | Channel Range | Primary Incumbents | PAL Allocation Limit | GAA Availability |
|---|---|---|---|---|
| 3550 - 3650 MHz | Channels 1 - 10 | US Navy radar, Satellite Earth stations | Up to 70 MHz maximum | Available on all unused channels |
| 3650 - 3700 MHz | Channels 11 - 15 | Grandfathered wireless ISPs, Satellites | None (GAA only) | Fully available for GAA access |
Frequently Asked Questions
What is the difference between LTE Band 48 and 5G n48?
Physically they occupy the same 3550–3700 MHz frequency range. Band 48 defines the LTE physical layer parameters, while n48 defines the 5G New Radio (NR) parameters, including support for wider subcarrier spacing.
Does the CBRS band exist outside the United States?
No, CBRS is a unique FCC regulatory framework for the US. However, other countries are adopting similar localized sharing frameworks for the 3.3 to 3.8 GHz mid-band spectrum (often called industrial 5G).
Is C-band (n77) the same as the CBRS band?
No. While they overlap, C-band (n77) in the US covers 3.7 GHz to 3.98 GHz and is exclusively licensed to major carriers. CBRS (n48) is a shared band covering 3.55 GHz to 3.7 GHz.