Tech Trends: CBRS May be the Key to 5G

June 8, 2020
The Citizens Band Radio Service accelerate the implementation of new high-speed networks
This article originally appeared in the June 2020 issue of Security Business magazine. When sharing, don’t forget to mention @SecBusinessMag on Twitter and Security Business magazine on LinkedIn.

As I was thinking about when to take that next step and upgrade my iPhone, I decided that it would make sense to wait until the next generation comes out (called iPhone 12 by some), since it has been hyped for its planned 5G capabilities. The phone is expected to use Qualcomm’s SnapdragonX55 modem chip, which supports up to 7Gb/s peak download and 3Gb/s upload speeds using both mmWave and sub-6 GHz frequency bands.

In my article about 5G transmission in July 2019 (, I wrote about low-frequency 5G network technology that uses existing cellular and Wi-Fi bands to improve on LTE – achieving speed increases of 25-50 percent. Higher frequency mmWave networks are optimal for short range, low latency and very high capacity transmissions, but with a more limited range and with limited indoor penetration; thus, they are best suited to dense urban and other environments.

I have since become acquainted with Matt Brown of HetNet Wireless (, which specializes in the design and test of wireless networks. I wondered aloud if I could ditch my wired Internet service in favor of tapping into a local 5G network – so began my education in CBRS.

What is CBRS?

In many countries, the mid-band spectrum – particularly the 3.5 GHz band – is a key piece of the 5G spectrum strategy. In the United States, a 150 MHz-wide portion of the 3.5 GHz band known as the Citizens Broadband Radio Service (CBRS) band, has been tapped for shared access applications and is now part of the 5G specification.

Sharing takes place along three dimensions – frequency, location and time. It will also make an impact on the wireless scene via 4G LTE private networks, providing adjuncts to cellular networks inside buildings.

Several companies have discussed building private LTE and 5G networks within large organizations and across corporate campuses using CBRS technology. “The auction for the 3.5GHz spectrum has been pushed back to July 23 due to COVID-related issues,” Brown says. “I expect that technology and spectrum constrained carriers will focus on denser urban areas to supplement their current networks and capacities.”

The FCC has established rules for access to this spectrum, employing three tiers:

  • Incumbent Access – primarily U.S. Navy radar operators and satellite ground stations;
  • Priority Access – via competitive auction, Priority Access Licenses (PALs) will be assigned for 10 MHz channels between 3550-3650 MHz in a single census tract (roughly, a neighborhood) for three years. Up to seven total PALs may be assigned in any given census tract with up to four PALs going to any single applicant; and
  • General Authorized Access (GAA) – users may use unassigned areas of the 3550-3700 MHz band not assigned to a higher tier user or on unused Priority Access channels.

To implement CBRS, an area must employ a Spectrum Access System (SAS) and have access to an Environmental Sensing Capability (ESC) network to dynamically manage the spectrum use. The SAS is an automated frequency coordinator that manages spectrum sharing on a dynamic, as-needed basis across the three tiers of access. It is a cloud hosted service that connects with Citizens Broadband Radio Service Devices (CBSDs) provisioned in the operator’s or private network.

The ESC is a network of sensors used to detect federal frequency use in the Priority Access band in protection zones where U.S. Navy radar systems can operate, primarily along the seacoasts. The ESC informs the SAS of radar operation, and the SAS reacts to ensure there is no interference with government operations.

A particularly interesting use case is that of private LTE networks. CBSDs would be deployed to individual building owners, often through a Mobile Network Operator (MNO) or Mobile Virtual Network Operator (MVNO), a smaller operator who buys space from one of the major network wireless carriers.

Fees for spectrum allocation are paid through the SAS, which administers either the PAL or GAA. One such company is Geoverse (, which advertises a “managed state-of-the-art connectivity solution including all aspects of design, commissioning, and operation delivered for a simple subscription price.”

Why it Matters

In addition to higher network speeds, there are a number of advantages to using this technology instead of Wi-Fi. One LTE small cell may supplant several Wi-Fi access points and provide better coverage, and the technology allows for configurable Quality of Service (QoS) – enabling prioritization of network traffic, including mission-critical and latency-sensitive traffic.

MNOs may offer roaming capabilities to enable devices to seamlessly move between private networks and established carrier networks. Also, security may be provisioned via SIM-based authentication, enabling users' mobile phone accounts for login to online services.

One example use-case that has been widely discussed involves colleges and universities, which are a natural for high-speed private wireless networks covering dormitories, academic buildings and university services, such as campus public safety.

Push-to-talk (PTT) functionality is also important to many campuses, according to CommScope. The company says new PTT over CBRS solutions will provide the higher quality that comes with a broadband voice network, along with added security and the ability to function as Wi-Fi hotspots.

“Motorola has developed a two-way PTT radio utilizing CBRS and offers it on a licensed agreement,” Brown says. “Other manufacturers are sure to follow with less prohibited products. This would enable deployment of a wireless network throughout a campus, with the ability to partition off space for security, maintenance, and other services’ radios.”

Other potential applications include manufacturing plants, corporate campus and building networks, stadiums, IoT networks and smart cities.

Ray Coulombe is Founder and Managing Director of SecuritySpecifiers and the CONSULT Technical Security Symposium. Reach him at [email protected], through LinkedIn at or follow him on Twitter, @RayCoulombe.