CBRS OnGo and the Private LTE Ecosystem
Physically separated from macro networks, private LTE networks are used for specific IoT applications and services. These networks enhance connectivity for use cases such as healthcare centers, industrial sites and offshore rigs. Either a mobile network operator or a private company can operate a private LTE network. Private LTE networks can operate in licensed spectrum as well as in shared spectrum.
Shared spectrum is a new kind of spectrum that is now available in North America as CBRS band 48 (3.55 GHz) and is becoming available in other parts of the world, such as Europe, Japan and other countries. Mobile network operators (MNOs) are interested because they can use this newly available shared spectrum to increase capacity and add more carrier aggregation (CA) channels. Other private companies are interested in offering a private LTE network running on this new spectrum.
The Strengths of Private LTE
Many enterprises are considering private LTE because of its unique strengths:
1. Seamless Connectivity
LTE offers the possibility of a smooth handoff from private to public networks for devices on the move. The evolved packet core (EPC) can be extended to achieve this, allowing the home subscriber server (HSS) to function in sites inside and outside the private network’s coverage realm. MNOs can share a network with other operators or use a third-party provider who deploys the EPC and negotiates with carriers to acquire roaming agreements. Enterprises also have the option of operating their EPC and handling any third-party negotiations needed for roaming services.
2. Enhanced Security
Private LTE keeps local data inside the corporate firewall on the premises, ensuring a higher security level. Security is built into LTE at every level, from devices to core, and each feature works together seamlessly. Private LTE is especially suited to connected things on the move, as it allows smooth handoffs to outside networks when they roam beyond the reach of onsite access points — without a loss of security. While cost (compared to Wi-Fi) can be a barrier to using public LTE carrier networks for IoT applications, private LTE brings the security of LTE with price points like Wi-Fi because the spectrum is shared and unlicensed.
3. Low Latency
In a private LTE network, data does not have to travel back to a core carrier network. Instead, it stays on the premises, making it possible for end-to-end latency to be controlled more tightly, a useful feature for smart manufacturing and other latency-sensitive applications. When latency is not essential to the application, an organization might choose to operate on a shared spectrum. Selecting a dedicated spectrum allows enterprises to achieve the lowest possible latency because there will be no interference from other traffic. This real-time functionality and minimized downtime risk enable edge processing — a crucial ability for many developing IoT applications.
4. Wider Range and Better Outdoor Coverage
LTE is inherently a wireless wide-area networking technology (WWAN), whereas Wi-Fi is a local area networking technology (WLAN). The difference between the two is range and outdoor coverage. Devices in an LTE network can operate at much longer distances from their base stations compared to Wi-Fi devices and their access points. Therefore, most of the private LTE networks can be made more extensive than other current wireless technologies, meaning that private LTE can perform better than Wi-Fi. Enterprises with outdoor sites, such as shipyards, mines, stadiums, RV parks, oil rigs, etc., need to install only a few small cells to provide a wide coverage area.
The Citizens Band Radio Service (CBRS) OnGo Network
So far, in the U.S., private LTE networks operate between 3.5 GHz and 3.7 GHz, a spectrum the Federal Communications Commission (FCC) has created as the Citizens Broadband Radio Service (CBRS), commercially known as the OnGo service. Currently, the U.S. Navy utilizes the CBRS spectrum for coastal and offshore communication, but they only use about 1% of the available spectrum, leaving ample opportunity for private use. The spectrum is divided into 15 channels, with seven licensed and eight unlicensed.
The CBRS Alliance manages the OnGo service and certification using a three-tier concept in order of priority level:
- Incumbents (U.S. Navy, fixed satellite)
- Priority Access Licenses (PAL)
- General Authorized Access (GAA)
Incumbents have prioritized access to the spectrum at all times. PAL and GAA users can request access to a channel via the Spectrum Access System (SAS), which manages priority between network users and an OnGo base station database. It uses environmental sensing capability (ESC) to detect when the U.S. Navy radar is active, notifying lower priority users to turn off or switch to another frequency. The SAS also manages priority between PAL and GAA users when the U.S. Navy is not actively using the system. PAL users pay for a license and get priority over GAA users. GAA is cost-effective, and many industries are interested because of its affordability.
Base Stations (CBRS Devices or CBSDs)
As noted, the SAS keeps track of all base stations in the network, including location and priority level, and administers the three-tier system for spectrum sharing. CBRS Devices or CBSDs (base stations or small cells) are separated into two classes:
- Class A is intended for low-power indoor use.
- Class B enables higher-power outdoor use.
Between these two types of components, an enterprise can create an entire private network, and everything related to the core network can fit into an on-premises network closet. Data never leaves the premises, making this a secure network option.
The CBRS Private LTE Ecosystem
While CBRS is relatively new, its ecosystem is already quite large, with many companies making private LTE a reality. Currently, there are five companies licensed to operate the CBRS’s SAS networks: Commscope, Federated Wireless, Google, Sony and Amdocs. These companies have installed their equipment along the coastal U.S. and operate with SAS servers to manage the devices.
Companies such as Expeto and Celona are working on an end-to-end networking stack for private LTE, while infrastructure providers like Ericsson, Nokia and Ruckus are scaling down public LTE equipment for use in Band 48 and smaller deployments. System integrators like American Tower provide an end-to-end system to private LTE network end-users.
End-user device providers, such as Apple, Samsung and Google, are including Band 48 support in their product and multiple SIM profiles, allowing the device to roam between private and public LTE networks. Gateways and routers are utilizing embedded LTE modules from Telit or other providers to complete the ecosystem.
As the CBRS ecosystem continues to grow in the U.S., it could become a model for spectrum sharing practices in other parts of the world. Private LTE is an affordable, efficient augment or alternative to Wi-Fi for many enterprises. As 5G emerges, it will bring much higher speeds and more capabilities to private networks.
Learn more about private LTE networking by watching our webinars titled “What You Need to Know about Private LTE Networking and Enterprise IoT” and “What You Need to Know about Private LTE Networking and Enterprise IoT: Your 100 Questions Answered.”