As cable operators form and evolve their mobile and wireless strategies, a swath of spectrum that’s opening up could very well take them down a new path that can not only enhance their existing offerings but also open doors to new ones.
That all centers on Citizens Broadband Radio Service (CBRS), a 150 MHz-wide batch of what will become shared-use spectrum living in the range of 3.55 GHz to 3.7 GHz. The FCC established rules for enabling that shared-spectrum band in April 2015.
That spectrum has been underutilized, with the bulk of it used by the U.S. Navy for flight operations for aircraft carriers, along with some satellite uplinks.
The FCC rules create a way to reapply that lightly-used spectrum to complement and enhance the limited pool of licensed spectrum that carriers have paid dearly for.
But the rules also support an engineering-focused approach to ensure that usage of the CBRS band doesn’t interfere with the incumbent users in the form of new spectrum allocation servers that are authorized by the FCC. Generally, those servers check for interference issues with the Navy, for example, before providing a spectrum grant in the CBRS band.
CBRS radios will need to be in constant contact with the spectrum allocation servers, and there’s work underway to build a sensor network along the coastline to detect Navy flight operations. If there is an interference issue, the radios would be commanded to move to a clean channel.
“It’s like a grand experiment,” Steve Martin, chief technology officer of Ruckus Wireless, said, noting that the coordinated, shared aspects of CBRS are unique.
CBRS is being set up as a three-tier system, with the top level for the Navy and other incumbents, a middle, priority access license layer that covers a portion of the band that will be tied to future FCC spectrum auctions, and a general authorized access layer. If licenses aren’t taken, that spectrum will also be open to unlicensed use.
That middle layer, Martin said, could be licensed by a service provider to hit a certain area that has a clear channel, and could also be cheap enough for an airport, for example, to license a 10 MHz slice to serve the facility.
One company that’s placing a big bet on CBRS and spectrum controller systems is Federated Wireless, which recently wrapped up a $42 million “B” round that included participation from two big names from the cable industry -- Charter Communications and Arris, which is in the process of acquiring Ruckus Wireless. The system Federated Wireless is building will run on a cloud-based service, network of sensors that identify and protect incumbent users of the CBRS band, spectrum sharing tools, and an “open” ecosystem for CBRS-based products.
“From our point of view, this is an absolutely fascinating area,” Duncan Potter, senior vice president of marketing, said of CBRS.
The rules around CBRS don’t speak to specific types of radios, but it’s viewed as a major opportunity for LTE-based technology. The CBRS Alliance (Federated Wireless, Comcast, Ruckus Wireless, Charter, Comcast and Cox are among its members ) is evangelizing LTE-based solutions in the CBRS band for in-building and outdoor coverage, holding in part that it will help to ensure product interoperability.
“It doesn’t take a lot of effort to move the needle on chipsets and that while ecosystem to support it,” Martin said, noting that the spectrum for CBRS is gaining momentum worldwide as an LTE mobile band. Theoretically, it could be implemented for WiFi, but that would make it unique to the U.S. and make it less commercially desirable, he said.
“The first segment of companies that are going after this are the cable companies, especially the leading cable companies,” Imran Akbar, vice president and general manager, wireless enterprise, at Samsung Electronics America, said.
But what, precisely will CBRS have to do with cable? Plenty of potential use cases are emerging.
The CBRS band could, for example, help MSOs get access to spectrum that augments the spectrum they are using in their MVNO deals. Comcast is using that model for Xfinity Mobile (with Verizon as the partner) and Charter has similar plans underway.
While the MVNO gets them into the mobile business, terms were negotiated years ago, with certain fixed costs, and it’s likely that Verizon wouldn’t be champing at the bit to give everyone a better deal.
It’s possible that cable operators will build CBRS-based small cells and supply the backhaul, effectively accessing capacity and spectrum that is less expensive than what comes way of their MVNO agreements.
Martin said it could make sense for an operator to build out CBRS infrastructure in areas with high concentrations of subscribers. When customers aren’t in reach of that network, they roam to the MVNO network.
“The economics are good for [CBRS] spectrum, and it’s good spectrum, too,” said Ralph Brown, chief technology officer at CableLabs, which is also a member of the CBRS Alliance and contributing to its scope of work. The CBRS work adds to that it’s doing with technologies such as WiFi and 5G. “The broader strategy we’re pursuing is to make sure our members have competitive positions in any one of those [areas], depending on what their business objectives are,” Brown said.
Cable operators might also use CBRS as a fixed wireless technology that helps them reach areas that are not covered by their wired networks, or as a solution for business service customers that want to beef up wireless coverage in their buildings.
Citing the airport example, Samsung’s Akbar said CBRS will open the door to “neutral host companies” that build the infrastructure there and sell access to carriers. That same model could be used in multiple-dwelling unit sites, he added.
Potter said the proximity of HFC and fiber networks make them well-positioned to backhaul CBRS-powered services, noting that their nodes are essentially “beachfront property” for such use.
But the exact timing of when this will all come together, though some in the industry hope it will be ironed out by the FCC in the first half of 2018, with buildouts to follow in the second half.
“We are neck-deep in trials today with cable companies and starting with some neutral cost companies and tower companies,” Akbar said, predicting that CBRS will begin to take off in a big way by 2020.
