CBRS stands for Citizens Broadband Radio Service, which is a wireless communication spectrum in the United States that was created by the Federal Communications Commission (FCC) in 2015. CBRS is a shared spectrum that allows commercial and private entities to use the frequency for various wireless applications, including 4G and 5G cellular networks, Wi-Fi, and other wireless services.

The CBRS spectrum operates in the 3.5 GHz band, which was previously used by the military and other government agencies. The FCC has opened up this spectrum for commercial use through a three-tiered access system. The first tier consists of incumbent users, such as the military and other federal agencies, who have primary access to the spectrum. The second tier consists of priority access license (PAL) holders, who can use the spectrum in a specific geographic area for a set period of time. The third tier is general authorized access (GAA), which allows anyone to use the spectrum on an as-needed basis.

CBRS offers a cost-effective and flexible solution for wireless communication, particularly in rural areas and for enterprise networks. It allows for increased competition and innovation in the wireless industry by providing access to a shared spectrum that was previously unavailable for commercial use.