CBRS, or Citizens Broadband Radio Service, is a band spectrum defined by the Federal Communications Commission (FCC). It is intended for commercial use to address wireless access demand. In 2015, the FCC adopted rules for CBRS, defining shared commercial use of the 3550-3700 MHz band (referred to as the 3.5 GHz band). The FCC finished the process of establishing CBRS in 2017.
On September 16, 2019, the FCC's Wireless Telecommunications Bureau and the Office of Engineering and Technology released a public notice. It reported that the Spectrum Access Systems (SASs) operated by Google, Federated Wireless, CommScope, Amdocs, and Sony have passed the commission's SAS lab testing requirements and are approved to begin their initial commercial deployments for CBRS. This approved the unlicensed portion of the 3.5 GHz CBRS band, known as the General Authorized Access (GAA) tier. The licensed part of the CBRS band (the Priority Access tier) may go up for auction as early as June 25, 2020.
In layman's terms, once the CBRS 3.5 GHz band is actively used, more devices can be online with better coverage. Even as IoT (Internet of Things) applications continue to drive an increase in internet-enabled devices and cell phone usage continues to demand more bandwidth.
Owners of buildings who have struggled with coverage or capacity will soon have access to a CBRS network, providing an additional solution, adding to the DAS (Distributed Antenna System) and existing WiFi coverage.
DAS currently provides an effective solution for increasing or boosting native cell signals within a building or across campuses and has been for decades. WiFi has provided wireless access for PCs and mobile devices over that same period. CBRS provides additional signal capacity; the offering includes a General Authorized Access level and a Private LTE with priority access licenses and general authorized access availability.
CBRS and PRIVATE LTEs
Currently, WiFi remains the prominent wireless technology for enterprise networks. CBRS may soon change that. Private LTE CBRS is built for large-scale industrial and commercial use to help answer the increasing demand for wireless solutions in buildings and across campuses. A private (CBRS) LTE will provide additional built-in Quality of Service (QoS), enabling prioritization based on the application.
LTE (Long Term Evolution) refers to 4g and subsequent cellular network generations (5g, 6g, etc.), designed to provide greater speeds than were available from 3G networks.
A Private LTE is a cellular network that includes cell sites and core network servers dedicated to supporting the connectivity of a specific organization's requirements independent of service providers' cellular networks.
The 3 Tiers of CBRS
Tier I - Incumbent Access
Incumbent Access users are grandfathered licenses for protection against harmful interference from Priority Access Licensees (Tier 2) and General Authorized Access (Tier 3) users. They include authorized federal users in the 3550-3700 MHz band, Fixed Satellite Service (space-to-Earth) earth stations in the 3600-3650 MHz band.
Tier 2 - Priority Access
The Priority Access tier consists of Priority Access Licenses (PALs) that will be licensed on a county-by-county basis through competitive bidding. Each PAL consists of a ten megahertz channel within the 3550-3650 MHz band. PALs are 10-year renewable licenses. PALs must protect and accept interference from Incumbent Access users and receive protection from General Authorized Access users.
Tier 3 - General Authorized Access (GAA)
The GAA tier is licensed-by-rule to permit open, flexible access to the band for the widest possible group of potential users. GAA users can operate throughout the 3500-3700 MHz band. GAA users must not cause harmful interference to Incumbent Access users or Priority Access Licensees and must accept these users' interference. And GAA users have no expectation of interference protection from other GAA users.
There is no question that the demand for wireless access will continue to grow, driven by cell phone advances and a growing number of IoT applications. Once fully implemented, it is equally certain that CBRS will be a major part of that growth.