Citizens Broadband Radio Service is a new block of 150MHz-wide spectrum in the 3.5GHz band (also known as C-band) primarily used by the federal government for radar systems. The Federal Communications Commission (FCC) assigned a frequency in the 3550 MHz to 3700 MHz range to enable private 4G-LTE networks a shared spectrum for public use in commercial wireless services. Each CBRS domain must have a spectrum access system making it lightly licensed. The CBRS band can boost users' 4G download speeds and is ideal for fixed or mobile 5G new radio (5GNR) delivery. This band remains strategic for future 5G roll-outs and replaces existing distributed antenna systems, providing high-speed data offload and in-building coverage. CBRS can replace last-mile fiber access to customer sites, deliver fixed-wireless services, and even point-to-multipoint connections. CBRS access points enable 10x cover over wider spans, outdoors or indoors. The many benefits of CBRS include enhanced mobility and range, Capacity, Optimized services, Interoperability, and speed.
FCC designates three tiers of users: Incumbent users, Priority Access Licensees (PAL), and Generally Authorized Access (GAA). PAL allows licensees to use the band in particular US counties. PAL has priority over GAA and licenses offered via auction (PAL were subject to auction, and ISP carriers like Verizon, Comcast, and others got approval). GAA can use any unused spectrum and yield to PAL and incumbents. It gives users the right to use the band if they don't interfere with the other two user categories.
CBRS 3.5 GHz, colloquially known as 'Band 48 CBRS', became available in the United States with a unique sharing paradigm. Among these three tiers of users, including satellite ground stations, the federal military incumbents have exclusive rights to the band. Verizon, for example, has deployed CBRS use band 48 for using 4G LTE technology, where band 48 is a subset of band 77. You may be using mid-band if your mobile is compatible with LTE 48, It is just not 5G. A CBRS-based private wireless network can offer continuous mobile coverage over a relatively large area compared to a Wi-Fi-based network.
These levels create new demand for operators looking to enter the mobile wireless market, facilitate a private LTE network for large enterprises, or cost-effectively expand capacity. It can also leverage the CBRS spectrum for IoT connectivity in an optimized, highly reliable, low latency, on-premise solution. Private LTE CBRS design is suitable for coverage in large enterprises, with higher power specifications and handoff capabilities that enable access points to deliver a higher range than Wi-Fi. The higher power levels allowed in that band will cause interference problems for the lower channels of the CBRS band. It has limitations in a macro-cell context.
A network of sensors—the Environmental Sensing Capability (ESC)—detects the use of CBRS. Devices that use the CBRS band first request a cloud-based Spectrum Access System (SAS) to reserve unused channels in a particular geographic area. The SAS can grant the requests if there are free channels. When permitted devices complete their tasks, the channels return into the pool that the SAS can draw from to grant further requests.