Citizens Broadband Radio Service (CBRS) – Everything You Want to Know

Citizens Broadband Radio Service (CBRS) is a shared wireless spectrum that was opened up by the Federal Communications Commission (FCC) in 2020. The spectrum is in the 3.5 GHz frequency band and allows both licensed and unlicensed access.

The CBRS spectrum is shared between different tiers of users. The highest priority access goes to incumbent military radar systems and other ‘grandfathered’ users. The next level is for priority access licenses (PALs) that were auctioned off to commercial entities that want dedicated spectrum access over a specific geographic region. The lowest tier is general authorized access (GAA), which allows any users to access the spectrum for free without a license when the higher tiers are not using it.

A key benefit of the CBRS band is that it offers mid-band spectrum that balances capacity and coverage area much better than other bands available today. Mid-band can carry substantial data loads over moderate distances, making it ideal for 4G/5G cellular, private networks, fixed wireless broadband access, and more. Unlocking this spectrum is helping bridge the digital divide and enabling next-gen technology. The unique three-tier sharing model also allows more intensive use of this spectrum compared to exclusivity licenses.

Shared spectrum refers to radio frequency bands that are made available for use by multiple types of users simultaneously. This is in contrast to exclusively licensed spectrum that is assigned to specific companies for particular services. Shared spectrum models have emerged to accommodate growing wireless demand within limited available frequencies. One such model is the three-tiered approach used for the CBRS band.

Several spectrum sharing frameworks have emerged to facilitate efficient utilization. Common approaches rely on databases to manage spectrum assignments by location and time. For example, spectrum access systems track priority levels and usage across a shared band, dynamically allocating vacant frequencies when and where needed. Geographic and time-based partitioning also help segment users, while power limits reduce interference.

Shared spectrum enables more intensive wireless usage within confined spectrum confines. It fuels innovation by opening access to valuable mid-band frequencies for enterprises and public applications. Key examples now harnessing shared spectrum include the CBRS band in the 3.5GHz range as well as the 6GHz and 5GHz unlicensed Wi-Fi bands.

In 2010, the US National Telecommunications and Information Administration (NTIA) identified the 3.5 GHz band as a potential solution to providing additional capacity, paving the way for a new era of shared spectrum usage.

In 2012, the Federal Communications Commission (FCC) officially christened the band as the Citizens Broadband Radio Service. This innovative approach marked a departure from traditional spectrum allocation, opting for a dynamic, three-tiered system. The core principle: government users would have primary access (incumbents), while commercial entities could compete for temporary licenses (PAL) or operate on a first-come, first-served basis (GAA).

In 2017, Kansas City and Las Vegas became the first major cities to trial CBRS, deploying pilot networks.

Finally, in 2020, the landmark CBRS auction brought the system to life. Priority Access Licenses (PALs), offering dedicated 10 MHz channels within the band, were snapped up by a diverse range of players, from established telcos to innovative startups. This marked a significant step towards unlocking the full potential of CBRS and democratizing access to valuable spectrum resources.

The OnGo Alliance (formerly the CBRS Alliance) is an industry organization formed to advocate for and promote the development, commercialization, and adoption of LTE and 5G-based solutions in the 3.5 GHz CBRS band in the United States. The Alliance was formed in 2016.

The main aims of the CBRS Alliance include driving technology developments to enable cellular-based solutions in the 3.5 GHz band, building an ecosystem of interoperable solutions via testing and certification programs, educating businesses and regulators on the benefits of CBRS spectrum, expanding the availability and use cases for CBRS spectrum through private licenses and shared access, and educating the world on the advantages of shared spectrum technology.

To achieve these goals, the CBRS Alliance engages in advocacy and public policy efforts to improve regulations around CBRS, facilitates testing and interoperability events for CBRS devices, operates the OnGo certification program for interoperability of solutions using CBRS spectrum, and works closely with organizations like the Wireless Innovation Forum (WInnForum) to oversee the Spectrum Access System (SAS) for CBRS frequency management and tiered access coordination between commercial users.

Authorized by the FCC and NTIA, the Citizens Broadband Radio Service enables commercial access to the 3550-3700 MHz band through a three-tier spectrum sharing system:

• Incumbent Access Users: U.S. Navy radar systems and several grandfathered operators continue to have priority rights to the band as they did historically. They operate across the entire CBRS band and have full protection from interference.
• Priority Access Licenses (PALs): Up to 70 megahertz can be assigned as 10-year renewable PAL licenses. These were allocated via a competitive 2020 FCC auction for terms up to a decade and have protection from General Authorized Access interference. The FCC has conducted two such PAL auctions already.
• General Authorized Access (GAA): The remaining CBRS band capacity is available for unlicensed use. These users must tolerate interference from incumbents and PALs. GAA access is dynamically granted and coordinated by the Spectrum Access System to maximize availability.

The Spectrum Access System (SAS) is the advanced frequency coordination system developed by diverse solution providers and certified by the Wireless Innovation Forum. It facilitates assessment of channel availability, grants/denies access to PAL & GAA users based on priority status and location and mitigates interference risks.

The CBRS network architecture includes several key components that provide a secure, reliable, and efficient wireless communication infrastructure. These components include:

• CBRS Devices: CBRS devices (CBSDs) are wireless devices that operate on the CBRS spectrum, including user devices such as smartphones, tablets, and laptops, industrial devices including drones, AGVs, and HD cameras, as well as infrastructure devices such as access points, base stations, LTE/5G and IoT routers, USB and ethernet adapters, and CPEs. These devices are designed to communicate with each other over the CBRS network and provide high-speed, low-latency wireless communication for a wide range of applications.
• Spectrum Access System (SAS): The SAS is a vital component of the CBRS network architecture that manages access to the CBRS spectrum. SAS systems are used to dynamically assign frequencies to CBRS devices and prevent interference between different CBRS networks. The SAS also monitors the CBRS spectrum for unauthorized use and ensures that all spectrum users comply with FCC regulations. The SAS is a cloud-based system that a third-party administrator operates.
• Environmental Sensing Capability (ESC): The ESC is another essential component of the CBRS network architecture. It is a network of sensors deployed primarily in coastal areas to detect the presence of naval radar signals in the 3.5 GHz band. If naval radar signals are detected, the ESC sends a message to the SAS, taking steps to prevent interference with naval operations. The ESC ensures that CBRS networks can coexist with military radar systems without causing interference.
• CBRS Radio Access Network (RAN): The CBRS RAN is the radio element of the CBRS network that connects user devices to other parts of a network through a radio link. The Radio Access Network (RAN) serves as a connection between user devices, such as cell phones, computers, and remotely controlled machines, and the core network. This link is established through a fiber or wireless backhaul connection. The link goes to the core network, which manages subscriber information, location etc.
• 4G/5G Mobile Core Network: The mobile core network is the backbone of the CBRS network architecture and provides connectivity between CBRS devices and the Internet or other networks. It includes the necessary infrastructure to transport data between the CBRS RAN and the Internet and the security and authentication mechanisms needed to protect the network from unauthorized access.

Three companies currently provide an ESC network: Federated Wireless, Key Bridge Wireless, and Google (formerly in partnership with CommScope).

The SAS providers include Google, Federated Wireless, Sony, Amdocs, and Key Bridge Wireless. CommScope retired from the SAS community in 2023.

CBRS offers organizations enhanced connectivity, cost savings, improved security, and greater control over their wireless networks.

By utilizing the 3.5 GHz frequency band, CBRS provides wider coverage and improved penetration compared to Wi-Fi, especially in large, congested facilities. Organizations can deploy private LTE/5G networks with dedicated bandwidth, bolstering reliability and security. Whether indoors or outdoors, CBRS enables flexible infrastructure deployments.

Additionally, CBRS reduces spectrum licensing costs and potentially monthly carrier fees by minimizing dependence on public infrastructure. Organizations can scale networks gradually according to current needs, avoiding major upfront investments.

Private networks facilitate tighter data security and consistent performance levels, without the public network interference that can disrupt mission-critical applications.

Beyond connectivity, CBRS unlocks innovation opportunities through custom applications and services. By supporting real-time data and workflows, it also streamlines operations and boosts productivity. Moreover, robust and secure networks enhance customer experiences.

For any organization handling sensitive information, requiring reliable performance, or operating in complex settings, CBRS grants invaluable independence and control. This technology warrants consideration as digital demands intensify.

CBRS and Wi-Fi are both wireless connectivity technologies but have key differences that make them suitable for varying needs.

Spectrum Access

• CBRS operates in the shared 3.5 GHz band, divided into access tiers with some licensing requirements.
• Wi-Fi utilizes unlicensed bands at 2.4 GHz, 5 GHz, and 6 GHz, and are prone to interference.

Range and Capacity

• CBRS provides wide-area coverage, with robust penetration for high capacity.
• Wi-Fi has shorter range and faces capacity limits from obstruction.

Deployment and Operation

• CBRS requires specific spectrum licensing and more complex infrastructure.
• Wi-Fi can be easily set up with no licensing but has less control over band sharing.

Network Architecture

• CBRS enables private LTE/5G systems with dedicated bandwidth allocation.
• Wi-Fi is built for wireless internet access, lacking native quality of service.

Performance and Security

• CBRS offers reliable performance and enhanced security with dedicated spectrum.
• Wi-Fi is impacted by interference and vulnerabilities.

Cost Considerations

• CBRS has higher build-out expense than Wi-Fi.
• Wi-Fi is generally more affordable but can require more maintenance.

Future-Proofing

• CBRS infrastructure can be upgraded to 5G standards (if started with LTE).
• Wi-Fi often requires replacement for next-generation compatibility.

CBRS is changing the way organizations connect and manage their Internet of Things (IoT) devices. Unlike Wi-Fi, CBRS offers a wider range of benefits, making it a compelling choice for various IoT applications.

CBRS overcomes Wi-Fi’s limited range with expansive coverage spanning large indoor and outdoor areas. Geographically dispersed IoT devices stay seamlessly connected regardless of location while strong signal penetration reaches devices in difficult environments like warehouses or underground.

CBRS allows the creation of dedicated LTE and 5G networks, freeing organizations from competing for shared bandwidth. The result – consistent high speeds, real-time data transmission, and reduced interference from other wireless signals.

Private CBRS-based networks safeguard sensitive IoT data from unauthorized access compared to Wi-Fi. This extra security gives peace of mind when handling confidential data or managing critical infrastructure. CBRS networks also smoothly scale to match the expanding needs of IoT deployments.

The CBRS spectrum offers several network solutions designed to provide businesses and organizations with reliable, high-speed wireless communication tailored to their specific needs.

• Fixed Wireless Access: CBRS-based Fixed wireless access (FWA) network solution provides high-speed broadband access to homes, businesses, and other locations not served by traditional wired broadband infrastructure. FWA is ideal for providing connectivity to remote or rural areas and backup connectivity in case of network outages.
• Private LTE/5G Solutions: CBRS-based Private LTE and 5G solutions provide businesses and organizations with dedicated wireless networks optimized for their specific needs. Private LTE/5G networks use CBRS devices such as base stations and access points to provide wireless connectivity over the CBRS spectrum, with higher security, reliability, and performance levels than traditional Wi-Fi or cellular networks. Private LTE/5G networks can be tailored to support various applications, including industrial automation, remote monitoring, and mobile workforce solutions.
• Neutral Host Solutions: CBRS-based Neutral host solutions provide shared wireless connectivity to enhance in-building public cellular coverage for businesses and organizations. Neutral host solutions are ideal for public venues such as airports, stadiums, office buildings, and convention centers, where individual and business subscribers of mobile service providers require cellular connectivity for voice and data services.

There are several key differences between CBRS devices designed for indoor use versus outdoor use.

Extensive outdoor coverage demands devices with higher power output. These effectively blanket larger areas and provide robust signal over longer distances, making them ideal for open spaces. Their directional or omnidirectional antennas strategically focus the signal or provide even distribution, catering to diverse coverage needs. Indoor devices, designed for smaller areas, utilize lower power output and omnidirectional antennas, delivering consistent coverage within buildings or rooms.

Outdoor CBRS devices prioritize endurance against the elements. Their robust enclosures and weatherproof materials shield them from rain, snow, extreme temperatures, and direct sunlight, guaranteeing reliable operation throughout the year. Conversely, indoor devices focus primarily on aesthetics and functionality within controlled environments, potentially lacking weatherproofing features and susceptibility to environmental extremes.

The enhanced capabilities of outdoor devices come with a cost premium. Their weatherproofing and power output translate to a higher price point compared to their indoor counterparts, which benefit from simpler designs and lower power requirements, resulting in lower costs.

There are many applications can that be implemented with a CBRS network for industries such as smart cities, healthcare, education, transportation, manufacturing, and warehousing. Some popular use cases are given below.

CBRS private LTE/5G networks can enable a range of applications for Smart Cities, enabling them to leverage shared spectrum for innovative wireless services.

• Enable real-time communication between vehicles, infrastructure, and traffic management systems.
• Use sensors and devices such as video cameras and gunshot detection sensors to monitor public safety.
• Provide connectivity for first responders and emergency services.
• Connect environmental sensors to monitor air and water quality.
• Provide high-speed, reliable, and secure wireless Internet access to citizens and visitors.
• Provide environmental monitoring applications for air and water quality.
• Connect sensors in waste bins to monitor fill levels.
• Connect smart parking meters and sensors to monitor parking availability.

CBRS private 4G/5G networks have the potential to transform healthcare by enabling innovative wireless applications that can improve patient outcomes and streamline healthcare operations.

• Telemedicine for video consultations, remote patient monitoring and care.
• Support mobile clinics, ambulances, and emergency medical services.
• Wearable sensors and implantable devices.
• Clinical communications among doctors, nurses, and administrators.
• Support virtual training and education programs.
• Location-based services: asset tracking and patient monitoring.
• Monitor hospital operations such as energy consumption, temperature control, and equipment maintenance.

CBRS networks can provide a range of applications for education, enabling innovative wireless services that can enhance the learning experience and improve educational outcomes.

• Digital learning initiatives, e.g., online courses, virtual classrooms, and educational applications.
• Improve campus safety with safety sensors and devices like video cameras and emergency call stations.
• Monitor campus operations such as energy consumption, temperature control, and facility maintenance.
• Enhance campus connectivity by enabling students and faculty to access educational resources and collaborate on projects inside and outside the classroom.
• Enable real-time communication among teachers, students, and administrators.
• Provide connectivity to outlier buildings and sports facilities.
• Offer support for contactless purchases including lunchrooms and vending machines.

CBRS networks can provide a range of transportation applications, enabling innovative wireless services that can improve transportation efficiency, safety, and reliability.

• Monitor traffic flow using cameras, sensors, and GPS tracking systems.
• Track vehicle and fleet performance, such as fuel consumption, engine performance, and maintenance schedules.
• Passenger Wi-Fi to enable entertainment, work, and communication during travel.
• Monitor parking availability.
• Support public transit applications for real-time transit information and fare payment systems.
• Provide reliable and secure wireless communication during emergencies.
• Connect autonomous vehicles.
• Improve freight and supply chain management.

CBRS networks can provide a range of manufacturing applications, enabling innovative wireless services that can improve operational efficiency, productivity, and safety.

• Connect sensors and devices to monitor industrial equipment, inventory levels, and asset locations.
• Provide real-time production monitoring.
• Provide sensors and devices to monitor worker safety with wearable and environmental sensors.
• Provide secure and reliable wireless communication among workers.
• Connect sensors and devices to monitor equipment performance, such as vibration sensors and thermometers.
• Enable energy management systems.
• Connect autonomous robots.

CBRS networks can provide a range of applications for warehousing, enabling innovative wireless services that can improve operational efficiency, inventory management, and worker safety.

• Connect sensors and devices to monitor inventory levels and asset location.
• Provide sensors and devices to monitor worker safety with wearable and environmental sensors.
• Enable real-time voice and data communications.
• Connect security cameras and sensors to monitor warehouse perimeter and access points.
• Enable warehouse automation using robotic picking and sorting systems and conveyors.
• Enable automated guided vehicles (AGVs) and automated storage and retrieval systems (ASRS).

While CBRS networks offer numerous advantages, there are some limitations to be aware of, which can nonetheless be addressed:

• Lack of Awareness: Many organizations and individuals are unaware of the benefits and potential of CBRS technology. This can make it challenging to gain traction and adoption.
• Competition from other technologies: Due to its competition with other well-established wireless technologies, such as Wi-Fi and cellular networks, some potential users may perceive CBRS as not yet mature enough for deployment.
• Spectrum Availability: In some locations, spectrum availability could be a challenge as availability of the CBRS spectrum can vary by location.
• Integration with Existing Systems: Integrating CBRS technology with existing wireless networks and systems can be complex, especially in large organizations with complex infrastructures.
• Limited Range: A CBRS network operates in the 3.5 GHz frequency band, which has a shorter range than lower frequency bands. This means CBRS coverage is generally limited to smaller geographic areas than other wireless technologies like public cellular networks. However, the limited range of CBRS networks can be beneficial for organizations that only need coverage in specific areas, allowing them to optimize network performance and reduce costs.
• Power Limitations: CBRS networks are subject to power limitations, which can impact coverage and signal strength.

• Spectrum availability: Although spectrum availability may be limited and obtaining PALs can be expensive, it’s an opportunity to create a fair and efficient use of the spectrum that benefits a broad range of users.
• Interference management: The 3.5 GHz CBRS band is shared with incumbent military and satellite users, so managing interference is crucial but complex.
• Rural deployment : The business case for deploying CBRS networks in sparsely populated rural areas can be difficult, yet extending wireless coverage to underserved communities is a goal. Creative business models may be needed.
• Device ecosystem : Although increasing, the ecosystem of CBRS-compatible devices is still limited compared to more established wireless bands. More certified devices from chipset and handset makers would drive adoption.
• Cost to migrate services: Transitioning existing wireless systems like private LTE networks to use CBRS can require investment in new hardware, software upgrades, and integration services. This can slow adoption where legacy equipment still has usable life.
• Understanding of shared spectrum : Concepts around spectrum sharing and SAS management are still unfamiliar to many organizations. Education on the technology, regulations, and benefits is important to drive utilization.

The OnGo Alliance looks at security from six domains: physical, authentication, encryption, network, software & application, and patching. Vulnerabilities can differ between industries. Protection must be checked at both the network and ecosystem levels.

As a cellular network, built-in security is part of LTE and 5G standards far and above alternative connectivity methods such as Wi-Fi.

For more information about CBRS and security, read the OnGo Security Whitepaper.

CBRS networks and solutions are poised to experience significant growth as private network demand continues to rise. Here are some trends and developments that are shaping the CBRS landscape and will impact its future:

• CBRS adoption is rapidly spreading across various industries and sectors. Healthcare, manufacturing, WISPs, airports, oil & gas, warehouses, hospitality, education, public safety, agriculture, utilities, military, large venues, and rural areas are all benefitting from secure and high-performance private cellular connectivity. CBRS is also enabling high-speed broadband connectivity in rural and underserved areas while providing a lower-cost neutral host connectivity option at public venues. The versatility of CBRS is making it a popular choice for enterprises looking for reliable and cost-effective connectivity solutions.
• The growth of the CBRS ecosystem over the past 3 years has been impressive, with more than 40 equipment vendors, 187 commercial CBRS base station models, and over 160 OnGo Alliance members joining the movement. The ecosystem has also been strengthened by the participation of 228 PAL auction winners, 450 authorized end-client devices, and over 900 different operators leveraging the freely available CBRS spectrum (GAA). Additionally, the presence of more than 4,000 certified professional installers has further boosted the growth of CBRS networks. This growth not only demonstrates the increasing popularity of CBRS technology but also shows the commitment of industry players to develop and advance the CBRS ecosystem.
• According to a forecast report by Dell’Oro group, LTE is expected to continue driving a significant portion of investments in the near term, with 5G NR-based CBRS Capex projected to dominate by 2026. This indicates a growing interest and adoption of CBRS technology in the coming years. While CBRS RAN revenues may account for less than 5 per cent of the North America RAN market by 2026, it is still a positive indication of the potential growth and expansion of CBRS networks in the region. The initial dominance of Fixed Wireless Access and capacity augmentation for Mobile Broadband (MBB) applications in the CBRS RAN capex mix presents opportunities for businesses to expand their services and offerings in these areas. As the enterprise share is expected to improve in the outer part of the forecast period, this presents further opportunities for growth and diversification in the CBRS market.

CBRS is a new and innovative technology that has the potential to transform the wireless industry. With its shared spectrum model, CBRS provides a cost-effective and reliable solution for businesses and organizations in need of wireless connectivity. As the technology continues to gain traction, we can expect to see further advancements and innovative use cases emerge. However, it’s important to note that CBRS also faces regulatory and technical challenges that need to be addressed for the technology to reach its full potential. Overall, CBRS is a promising development that warrants attention from businesses, wireless service providers, and technology enthusiasts.