CITIZEN BROADBAND RADIO SERVICE (CBRS) is a new technology in the US that leverages the 3.5 GHz band to introduce a new framework for spectrum sharing among incumbent users (military, satellite earth stations and WISPs) and new commercial users. For the first time, the spectrum will be flexibly and dynamically shared ensuring interference protection while coordinating user access. A novel three-tier sharing paradigm coordinates spectrum access among Incumbent, Priority Access License (PAL), and General Authorized Access (GAA) users.
Incumbents are protected from PAL. The PAL users are protected from GAA users. This is made possible by the Spectrum Access Systems (SASs) that have been created to dynamically monitor and authorize use of specific spectrum resources for PAL and GAA users based on geolocation databases and management policies. The SAS maintains a database of all CBRS base stations, the Citizens Broadband Radio Service Devices (CBSDs), including status and location coordinating channel assignments and managing potential interference.
Environmental sensors known as the Environmental Sensing Capability (ESC) will be deployed in strategic locations, mostly along coastal regions, to detect incumbent activities, alerting the SAS which then directs CBSDs to move to free CBRS channels.
The CBRS defines two classes of base stations: class A and class B.
- Class A base station is an indoor or low power outdoor small cell with a maximum conducted power of 24 dBm (per 10 MHz) and maximum EIRP of 30 dBm (1 watt). This is mostly used for indoor GAA.
- Class B base station is meant for outdoor use with a maximum EIRP of 47 dBm (50 watts). With a very high-gain antenna, outdoor CBRS base station can potentially be used for fixed wireless purposes.
The CBRS has made it possible for private network providers to offer 5G/LTE/3G services on unlicensed spectrum. This has provided much needed impetus to deploy private LTE networks today in “wiFi mode” with much better coverage, throughput and performance. This capability is especially important for providing connectivity, multi-media services and IoT applications in remote / rural areas and in market segments such as mining, agriculture, oil & gas and other industrial segments. CBRS also enables the ability for customers to deploy mobile edge compute networks with intelligence closer to the end user. This facilitates many business and mission critical applications which were hitherto hampered by congestion and delays of the core network. These MEC networks can also be better managed and monetized since analytics are immediately available to the enterprises deploying the network. Lastly, cellular IoT application deployment has become possible with NB-IoT base stations and devices being effectively deployed over CBRS.
Azcom Technology provides access networks solutions to the CBRS market with a family of base station products. Class B IP67 compliant Pico and Micro Cells with 4W and 10W total output powers respectively, along with NB-IoT and NIB capabilities are well suited to build private enterprise networks where performance, resource usage, priority access, security are fully under control of the enterprise.
For higher powers (20 W per channel or more), more powerful Class B solutions with remote radio head distributed architecture are also available. Maximum EIRP can be achieved with a low/high gain omni-directional antenna.
Deploying LTE on CBRS band is convenient and attractive for private enterprises because they have a solution that is potentially independent of the licensed mobile operators. CBRS solutions can be especially convenient for deployments in warehouses, factories, oil & gas, mining, farms, utilities, production critical industries, transportation, logistics, shipping ports, campuses and locations not covered by public infrastructure.