What Is CBRS and How Does It Help IoT?

The Internet of Things continues to grow fueled by applications that solve problems for enterprise customers. One of the biggest barriers to IoT solutions in enterprise settings is reliable and low-cost wireless connectivity. Where Wi-Fi, Bluetooth, LoRa, Zigbee and others have tried to solve the problem before, CBRS (Citizens Broadband Radio Service) is posed to offer a viable alternative for enterprise IoT connectivity.

What is CBRS?

Specific to the United States, Citizen’s Broadband Radio Service (CBRS) is a piece of the radio spectrum between 3550 - 3700 MHz. This is a valuable area of the spectrum because it allows good propagation (ability to penetrate walls and go medium distances) with the benefits of higher bandwidth services, such as LTE and 5G.

CBRS spectrum can be used to deploy a stand-alone, private LTE or 5G network inside a building.

Before CBRS, ensuring a robust cellular network inside of a facility, like a hospital, required installing a carrier-specific Distributed Antenna System (DAS). These systems are costly and only work with one carrier. CBRS systems have the potential to offer a “neutral host” for LTE/5G connections which would connect cellular devices (like phones or IoT sensors) via the CBRS radio infrastructure and then on to the carrier’s packet core network. For phones (and there are not many out yet) that support CBRS, they could use these in-building networks independent of what mobile operator they are using. 

For an IoT device inside of a building, using CBRS could prove a much more reliable connection than trying to connect from the basement HVAC controller to a cell tower 2 miles away, for example. 

Business Benefits

Neutral Host IoT Connectivity

For a direct-to-cellular IoT device (like a pharmacy temperature monitor in a hospital) that is installed in an enterprise, using CBRS as the primary cellular connection could be free if the device was provisioned to participate directly on the enterprise CBRS system. No need to pay Verizon, if the enterprise is providing all of the components for connectivity.

Alternative to Wi-Fi

CBRS 4G/5G systems use radio technology that is much more advanced than Wi-Fi and can cover 3-4x the range even at equivalent power levels. And since security and access are controlled via SIM cards, many of the headaches of managing Wi-Fi access and security are alleviated for IT teams. 

Better Performance Than LoRa or Zigbee

IoT specific wireless technologies like LoRa or Zigbee often use an application layer routing design, which means that some of the flexibility and robustness of the IP network are unavailable. Things like firmware upgrades and service changes are much easier for direct-to-IP connections like those enabled with CBRS 4G/5G.

Broadband Phone and Data Services

IoT is not the central Applications for CBRS. It is the ability to improve phone performance in buildings that is the main value driver. IoT networking becomes a nice-to-have add-on for CBRS investments, at least at this stage. Alternatives to Wi-Fi for other devices, like laptops and TVs are likely to be seen in the future of CBRS enabled buildings.                                          

CBRS Applications

Good IoT applications for CBRS are ones that require a lot of bandwidth and probably aren't battery-powered. Such as:

• Video - Surveillance or Computer Vision Applications
• Real-time control- Building Automation, HVAC
• Push-to-talk- Security, operational voice such as in healthcare
• Mains powered sensors- Temperature, Air Quality 
• Gateway based IoT - Indoor positioning, where sensors talk to a local gateway

Indoor Positioning Example

CBRS could be a potential candidate for secure, high-bandwidth backhaul and long-range connectivity for campus-wide IoT solutions of the future. What makes CBRS attractive compared to Wi-Fi is the range the can be supported from a single access point, mobility support for users on the move, and spectral efficiency/capacity to support a large amount of traffic. 

Architecture for Private LTE Networks

For high-reliability Applications or those in environments already plagued by complex IT systems and crowded unlicensed band usage, like hospitals, CBRS could open up a new capability to install IoT solutions. Indoor positioning systems that rely on Bluetooth or Ultrawideband often have high frequency, real-time data flow requirements that can be challenging for Wi-Fi-based backhaul. CBRS small cells connecting to CBRS IoT gateway devices could provide a new way of solving the backhaul problem.  

For CBRS-based IoT networks, the near term challenges are how device management (SIM-based security and provisioning) will be handled and the limited availability of CBRS capable gateways and sensors. Companies like Athonet are working to solve the software and orchestration problems created by new CBRS enterprise deployments. 

Potential Barriers

Country-Specific

CBRS is solidly a USA-only spectrum band. However, other countries are releasing the public spectrum for unlicensed broadband wireless as well. The downside is that each country will require specialized radio hardware to work in a certain band. As these bands take off, cellular module manufacturers are likely to incorporate them. A “private cellular only” module might be on the market in the next few years.

Licensing Details

CBRS is a hybrid of licensed and unlicensed spectrums. 70 MHz out of the 150 MHz total bands are available through auctions, which will likely be consumed by the mobile operators. The remaining 80 MHz is available as General Availability. 80 MHz is still a large amount of spectrum to do private cellular operations. However, just like congestion in the 2.4 GHz band, CBRS GAA spectrum will likely see more and more use over time. 

Customer Availability

For an IoT company looking for connectivity options, CBRS should be on the radar, but it is certainly too new to rely on just yet. Unless an application is very valuable, the cost of deploying a standalone CBRS network just for IoT likely won’t be justified. Waiting for customer sites to adopt CBRS is likely the strategy that the IoT community will have to adopt.

CBRS is an exciting leap forward for publically available spectrum in the US. How it will play out for enterprises and the IoT community will be very interesting. Watch this space.