Kurt Schaubach brings 25 years of wireless industry experience to Federated Wireless where he plays a key role in developing technologies and new business strategies to create the next-generation architecture of broadband wireless.
While you might not realize it, the sharing economy — built around software-based systems that manage services by partnering customers with suppliers in real time (such as Seamless, AirBnB and Uber) — strongly mirrors what we’re doing with shared spectrum for the 3.5 GHz band. There is a finite amount of spectrum to support mobile services, while demand for wireless connectivity continues to increase exponentially. As connected devices rapidly grow in number, size and complexity, shared spectrum offers a new mechanism for matching wireless demand with supply to support new services while ensuring spectrum doesn’t sit idle.
During the mid ’90s when mobile phones gained mass adoption, mobile networks were built through competitive auctions for exclusive spectrum licenses. At the same time, large swaths of spectrum were allocated for federal use. Today, nearly 60 percent of low- and mid-range spectrum, which can travel far with great reliability, is reserved for non-commercial use.
In 2012, when the framework for shared spectrum for the 3.5 GHz band was first proposed, the technology to implement it just didn’t exist. Since then, an entire ecosystem has sprung up with over 80 companies across every segment of the industry coming together to join the CBRS Alliance. Here at Federated Wireless we took advantage of advancements in machine learning and cloud computing to develop our Spectrum Controller, a scalable system that dynamically automates connectivity to the 3.5 GHz spectrum band so that it can be securely shared for both commercial and federal use.
Since taking on the challenge of developing a solution to open up access to 3.5 GHz over five years ago, it’s exciting to know that we’ll see spectrum sharing come to market this year. And, over the next five years, we expect to see spectrum sharing rolled out to several more bands both in the United States and globally, inevitably expanding to support 5G technologies.
Software-defined solutions are enabling new possibilities for how spectrum is used and shared, allowing greater efficiency in how we manage what’s available. It’s a safe bet: shared spectrum is the future of wireless connectivity.
Last week marked another milestone in the progress toward CBRS commercialization. Keeping their public commitment to move quickly on resolving final rule changes, the FCC proposed revisions to its rules in the 3.5 GHz CBRS Band. The FCC’s Notice of Proposed Rulemaking (NPRM), Promoting Investment in the 3550 – 3700 MHz Band, seeks industry comment on changes to the rules governing Priority Access Licenses (PALs). The proposed changes include PAL area sizing, longer license terms with the possibility of renewal, and modifications to the rules governing license auctions and secondary market transactions.
Interest in the 3.5 GHz CBRS Band has grown steadily since 2015 when the FCC first established rules. It is now clear that the CBRS band will be the foundation for next generation network deployments serving a myriad of use cases including: Network Densification, Neutral Host, Private LTE, and the Internet of Things. As interest has grown, some have expressed concern that the current Priority Access License rules do not promote long-term investment and robust network deployment. Others in the CBRS ecosystem have countered that the existing rules promote innovation and investment from new entrants by reducing the barriers to entry. This new NPRM is designed to address the concerns of all parties.
The action the FCC took last week was anticipated, and we view it as a positive step forward for several reasons:
The FCC is working expeditiously on rule changes, indicating that it is serious about sticking to the timeline it provided to the industry.
The NPRM is focused almost entirely on the PAL rules. The FCC was careful not to reopen other issues that were previously resolved.
The proposed rules in the NPRM do not have a bearing on the General Authorized Access (GAA) tier of service. Therefore, the ongoing process of SAS and ESC certification can continue without delay, quickly followed by the offering of commercial services in the band.
The NPRM did not provide a specific proposal for PAL license areas – leaving room for continued industry negotiations. The FCC appears to be open to compromise proposals on this matter, including a hybrid approach of both larger and smaller license areas. This indicates that the Commission is listening to the interests of all parties who see opportunity in the CBRS band, from the largest Mobile Network Operators to the smallest rural Wireless Internet Service Providers.
The FCC has restated their commitment to move quickly to gather new comments and adopt final rules. Once the NPRM is published in the Federal Register, there will be a comment period of 30 days, followed by a reply comment period of 30 days. Assuming a publication date of mid-November, comments will be due in mid-December and reply comments in mid-January. FCC leadership will then consider the filed comments, and final rules – in the form of a Report and Order – are anticipated in March 2018.
Again, we see this as a positive step forward, one that gives the industry confidence in the viability of the shared spectrum framework and the opportunity it offers the wireless industry. While final PAL rules are determined and PAL auctions established, the CBRS ecosystem is running trials and validating the deployment models and business models that will lead to commercial GAA services by the middle of next year.
Today I want to focus on the cognitive engine that is the foundation of the CBRS shared spectrum architecture: the spectrum controller. Many of you are familiar with the management function of a controller in a network. For example, a Wireless LAN controller dynamically directs and regulates traffic in a carrier Wi-Fi network, and can be used to set and apply policy. It integrates with a carrier’s operational and business support systems (OSS/BSS) for management and billing. For efficiency and scale, controllers are increasingly implemented as cloud-based software.
The spectrum controller plays a similar role in the CBRS network architecture, with the addition of some unique features. The spectrum controller acts as the Spectrum Access System (SAS) to enforce the three-tier spectrum-sharing framework adopted by the FCC for CBRS. The novel three-tier sharing framework coordinates spectrum access among the incumbent military radars, satellite earth stations, and new commercial users. The three tiers of use are Incumbent, Priority Access License (PAL), and General Authorized Access (GAA).
Figure 1. The Three-Tiered Spectrum Access System (SAS)
The spectrum controller is an advanced, highly automated radio spectrum coordinator, tasked with protecting the higher-tier users from lower-tier users and optimizing efficient use of the available spectrum in the CBRS band for all users. As a result, the 150 MHz of the CBRS spectrum is dynamically shared. The controller maintains a database of all CBRS radio base stations including their tier status, geographical location, and other pertinent information to coordinate frequency and transmit power assignments and to monitor and protect the band from potential interference.
Per the FCC rules, at least 80 MHz of spectrum will be available for General Authorized Access (GAA) use (assuming no Incumbents are present), and in some cases, the full 150 MHz will be available if there are no Incumbents or Priority Access users in an area. The spectrum controller applies a series of sophisticated algorithms to ensure that FCC rules are enforced at all times while giving maximum access to the available spectrum. An important aspect of the architecture is that users of shared spectrum resources are always under the authoritative control of the SAS. This assures protection of the top-tier incumbent users, which is especially important for federal users.
Federal use of the 3.5 GHz band is relatively rare, but vital when needed. That’s what made this band so attractive for commercial use and so viable for the shared spectrum model. To help ensure that Federal Incumbents are always given the highest priority access, the Federated Wireless Spectrum Controller includes Environmental Sensing Capability (ESC) sensors. ESC sensors are deployed along the U.S. coastline so that Naval radars operating in 3.5 GHz are protected from any interference by shared spectrum users. ESC sensors securely detect shipborne Incumbent use and inform the SAS, which reallocates shared spectrum users to other available channels within the 3.5GHz spectrum band.
The spectrum controller also includes incumbent protections for Fixed Satellite Systems and other grandfathered Wireless Internet Service Providers through exclusion zones and the utilization of aggregate interference data. The controller applies this real-time sensing and database information to enforce the hierarchical spectrum sharing regulations and determine spectrum availability and assign spectrum to individual radios or networks of radios. This is all done in a fair, secure, and dynamic manner, without the need for manual intervention and without interruption to either incumbent or commercial services.
In addition to providing these SAS and ESC functions, the spectrum controller also provides insights into design, planning and operational analytics through the entire lifecycle of a CBRS deployment. These capabilities are deployed as scalable cloud-based systems for ease of automation and programmability. An open and standards-based set of APIs ensure the architecture works with any Citizens Broadband Radio Service Device (CBSD). It also allows for interfaces with OSS/BSS systems for the integration of business functions like policy, billing and management. The software-defined spectrum controller is a natural extension of the move to an open and software-defined paradigm.
Figure 3. The Functions of the Cloud-Based Federated Wireless Spectrum Controller
The wireless world is becoming more sophisticated every day in response to the growing demand for cost-effective bandwidth. Federated Wireless is working with the CBRS Alliance to commercialize all the elements of the CBRS architecture so that the spectrum controller and CBSDs can be deployed quickly and with the confidence that they are interoperable and meet industry standards. The standards are in place, the enabling technology is available, the ecosystem is growing rapidly, and FCC certification is imminent. What’s so exciting about this new development in the wireless market is the wide range of existing and emerging applications that it makes possible – enabling new business models to efficiently deliver LTE services.
It was a genuine pleasure to listen to David Redl’s recent Senate testimony in support of his nomination as Assistant Secretary for Communications and Information and Administrator of the National Telecommunications and Information Agency (NTIA). In the NTIA’s role as principal adviser to the President on telecommunications policies, they are responsible for managing federal government spectrum. Redl reaffirmed the NTIA’s commitment to find ways to protect federal mission-critical interests while promoting commercial use of spectrum – the essence of the CBRS spectrum sharing scheme that the NTIA and FCC helped develop.
In case you don’t have time to listen to the entire hearing, here are some of my favorite quotes from Redl’s testimony:
“Spectrum is the invisible infrastructure of our digital economy, and it enables our increasingly mobile society”
“Demand for spectrum continues to grow as smart cities, connected cars, and 5G wireless technologies become closer to widespread deployment.”
“My commitment is that the needs of our national government spectrum users are balanced with the continuing need for additional licensed and unlicensed commercial spectrum.”
“We will continue to search for new efficiencies to protect the federal interest in their missions while promoting commercial use. It will take some ingenious approaches on both sides, but we have to be creative.”
“There is always an opportunity for more efficient use of spectrum, and that’s the ongoing challenge, and frankly the fun, of working on spectrum policy.”
It’s just this kind of passion and commitment to innovation that led to the creation of the CBRS shared spectrum program, which is nearing commercial deployment later this year. We look forward to Redl’s confirmation in this role and to continuing to work with the NTIA and FCC on improving shared spectrum use as our technology continues to mature.
There’s been a lot in the news lately around momentum for the 3.5 GHz shared band. Having just returned from a CBRS Alliance members meeting in Denver where this was the main topic of conversation, I can tell you that the momentum for shared spectrum is already very strong and is building rapidly.
Last week, our team met up with more than 100 representatives of the 40+ companies that make up the CBRS Alliance. What started in early 2016 as a commitment from select industry leaders to foster the development of LTE technology for the CBRS band has quickly turned into a broad industry alliance of passionate experts from leading wireless technology companies seeking to do much more. It isn’t so much about standalone products as it is about putting standards and processes in place to create a strong foundation upon which we can then make shared spectrum a commercial reality. Together, we are proud to represent the entire CBRS ecosystem, and we are now fully formed with all four U.S. mobile operators, top cable operators, tower companies, equipment vendors, and chipset makers.
Figure 1: Lots of interest in the Juni demo, which included a Band 48 MiFi device
As the Alliance continues to grow, folks have been asking us about market readiness. I saw several live demos at the meeting, and I would say maturity levels towards commercialization were clearly evident. Nokia showed a demo of their prototype CBRS (Band 48-compliant) small cell. Ruckus’ CBRS LTE v. Wi-Fi demo showed a substantial performance advantage to LTE. Their 1-watt small cell achieved phenomenal range and throughput. There were other good demos from ZTE and Accelleran, and Juni’s demo of a Band 48 prototype MiFi device generated lots of interest. All of the over-the-air demos were accessing the 3.5 GHz spectrum through the Federated Wireless Spectrum Controller.
What was just as exciting to witness was the interactive and energetic dialogue around the current model for the 3.5 GHz shared band. Strong interest has developed across many market segments in the current model. The existing three-tier SAS framework has numerous merits, perhaps the most important being the assured protected use of federal and commercial incumbents. It became clear during the course of the meeting that many companies are planning to make commercial use of the band later this year. Our own spectrum controller has been put to the test and will be ready for commercial launch later this year. We intend to support full CBRS spectrum access in the U.S. by the end of the year.
Overall, it was a productive meeting that further cemented the Alliance’s commitment to seeing LTE-based solutions utilizing the shared spectrum of the 3.5 GHz CBRS band come alive this year.
Figure 2: CBRS Alliance Executive Team addressing a packed house at the opening plenary
It’s official. This week President Trump appointed Ajit Pai Chairman of the Federal Communications Commission. Pai is a senior FCC Commissioner, and this quick action will help to maintain leadership and stability within this important government agency. I see this as particularly important to the Citizens Broadband Radio Service (CBRS) to maintain momentum toward full commercial use of the band.
In the past Pai has spoken passionately about the need to encourage innovation with shared spectrum: “The FCC would like to test a theory — to see if we can implement a sharing regime that will allow a mix of innovative offerings to flourish. Have we struck the right balance? Will we see a variety of providers and technologies competing in the band? I can’t say for sure. It remains to be seen whether we can turn today’s spectrum theory into a working reality,” – Ajit Pai, April 2016.
Since then, the industry has rallied around the 3.5 GHz CBRS band. Here are just a few of the milestones achieved:
As Pai states, the bright industry minds who are finding elegant new solutions to share spectrum will open up an untouched frontier for business and technical innovation. We are discussing new value chains, new business models, and a host of new services that will be made available when spectrum that was once locked is made available to securely and cost-effectively share. The spectrum sharing experiment that the FCC initiated is becoming reality, and Federated Wireless is leading the way.
Image courtesy of Sira Anamwong at FreeDigitalPhotos.net.
About Kurt Schaubach 
