As the world grows increasingly dependent on wireless devices, networks, and services, one thing has become readily apparent: open radio frequency spectrum—that is the space in which wireless signals can be sent—is an incredibly valuable asset. Long-time telecom industry observers and participants have known this to be true for some time, but events like the COVID-19 pandemic are now making a much wider audience of people—everyone from general tech industry leaders, government officials, and even technically literate consumers—understand its importance.
The challenge is that, in a country like the US with an incredibly long, rich history in wireless innovations—from the early days of over-the-air radio and TV transmissions through the era of CB radios to today’s 5G cellular networks—the once open roadways of radio signal transmission have become as packed as the highways big-city rush hours. And, just as there are few easy answers to deal with traffic congestion, finding ways to send significantly larger amounts and more types of wireless data over the physically limited capacity of viable radio spectrum is a problem. (If you’d like to learn more about frequency and radio spectrum issues, check out “The 5G Landscape, Part 2: Spectrum and Devices”, which provides a thorough explanation in plain English.)
Thankfully, over 10 years ago, members of the US Federal Communications Commission (FCC) and other governmental officials foresaw some of these RF congestion problems and started work on an experimental project that would allow frequencies, which are typically restricted to use by one specific company, governmental agency or industry, to be shared among many different companies. The first fruits of that 10-year spectrum sharing experiment is the new CBRS (Citizens Broadband Radio Service) which, despite the similar name, has absolutely nothing to do with the CB radios often used by truckers. CBRS also goes by the friendlier (though still slightly obtuse) OnGo name. It uses a sophisticated signal rationing technology to dynamically assign up to 150 MHz of RF spectrum that had been previously allocated solely to the US Navy across two potential tiers of users: companies that pay for a dedicated Preferred Access License (PAL) and General Authorized Access (GAA) for general purpose unlicensed use, much as WiFi works today (See “CBRS Vs. C-Band: Making Sense Of Mid-Band 5G” for more.)
The details of how it all works can get complicated quickly, but the bottom line is that the spectrum sharing technologies that enable CBRS serve as a novel means to free up some precious spectrum assets. Those assets are expected to be used to create new types of products and services—such as private cellular networks for companies—and to increase the robustness of existing networks. Most of the initial efforts to use CBRS will take advantage of and work alongside 4G LTE wireless networks and technology, but because the CBRS frequencies (between 3.5 and 3.7 GHz) are in the highly-coveted “mid-band” range of 5G frequencies, the transition to enable it for 5G use is expected to happen quickly.
One important additional detail about CBRS-capable transmitters, not previously mentioned, is that there are two different types: Class A, which is limited to 1 watt of transmission power and designed primarily for indoor applications, and Class B, which allows for up to 50 watts of transmission power and is expected to be used more for outdoor applications. This higher power level means that CBRS radios could potentially be used to supplement the bandwidth of existing cellular wireless networks. The challenge for carriers is that over 22,600 separate CBRS PAL licenses will be auctioned off this summer on a county-by-county basis. Stitching together all the necessary CBRS and traditional macro cell tower signals into a single unified service will be no small feat, but it certainly represents an important opportunity for telco providers to increase the bandwidth of their networks.