December marks a year that shared spectrum networks using the Citizens Broadband Radio Service (CBRS) band have been in full commercial operation. Federated Wireless CTO Kurt Schaubach says in a blog post that “well over” 100,000 CBRS radios have been deployed.
At the core of the deployment of shared spectrum is a sensor network that can securely detect when naval radar needs access to a portion of the spectrum. Commercial users can then be moved onto other channels, ensuring maximum spectral efficiency. This is the Environmental Sensing Capability (ESC) network. Both Federated and Google operate as SAS administrators; Google and CommScope jointly developed an ESC.
In public forums and FCC filings, Google recently raised what Federated calls a “disingenuous concern” that the ESC network is a failure, and that regulatory bodies and the industry should consider an alternate approach through which the Department of Defense inform SAS administrators when it’s planning to use shared mid-band spectrum – called Incumbent-Informing Capability (IIC).
According to Federated, IIC is not a new idea. It was discussed at length and ruled out in favor of ESC prior to the CBRS rules being set in 2015. “The FCC and DoD agreed then, and still maintain, that deploying a sensor network is preferable and necessary due to the security and operational risks introduced by deploying an IIC,” writes Schaubach.
IIC networks today require manual input and maintenance, and so introduce the possibility that the largest commercial networks might be taken down by simple human input error. However an IIC can be reliable, secure and accurate if the input can become foolproof, perhaps through automation, notes Schaubach. “IICs may well become the best option for spectrum sharing in the future, which is why the National Telecommunications Information Administration is opening the discussion once again.”
Federated has “extensive” experience building IIC-like technology. It built the Radio Frequency and Interference Monitoring System for NOAA. The company says it’s teaming with world class personnel to develop effective IIC technology. “We know from experience that to do it right will take years of development, testing, and operational training,” notes Schaubach.
“As with any futuristic endeavors, the question is whether we want to do nothing while we wait. Google’s recent public stance is nothing more than an attempt to revise history and bypass necessary steps in the deployment of shared spectrum based on the fact that it’s a lot easier and less costly to submit an FCC filing than it is to successfully deploy an ESC network,” states Schaubach.
Federated’s ESC network has been deployed nationwide since May 2019, with live commercial traffic since September 2019. Since then, the company has been working to eliminate false positive data, and reduce the impact of the ESC network itself on commercial CBRS use. Schaubach says the company is not seeing the problems that Google cites in its FCC filing. “We have heard from customers that Google is having massive problems with the sections of their ESC network that they have only recently deployed, so we believe that’s the root cause of their objection. Many customers who are deploying along the coastlines are switching to our SAS/ESC for just this reason.”