Many Questions Remain About Likely Popularity of 3.5 GHz Band

A key deadline looms. The “first wave” of companies interested in becoming spectrum access system (SAS) administrator and environmental sensing capability (ESC) operators is set to file proposals at the FCC Monday. The rules developed by the FCC set up experimental three-tiered access and a sharing model made up of federal and nonfederal incumbents, PALs and general authorized access (GAA) users. The band can't be used within exclusion zones set up to protect Navy radars.

Michael Calabrese, director of the Wireless Future Program at New America, told us he expects wireless industry participation in the band. “There appears to be widespread and serious interest in the band by mobile carriers and their network equipment suppliers,” he said. “A sizeable number have been participating actively in the WinnForum [Wireless Innovation Forum] multi-stakeholder process that is working out implementation details. Since the 3.5 GHz band is already standardized for use in Europe, chips are available and could begin showing up in smartphones and small cell wireless access points next year.” Calabrese has been active in the WinnForum process.

Commissioner Mike O’Rielly openly questioned whether carriers will participate. At the recent FCC meeting at which commissioners approved tweaks to the 3.5 GHz rules, O’Rielly said the three-year license terms for the PALs mean carriers are unlikely to pursue them in an eventual FCC auction (see 1604280062). “Outlook for 3.5 GHz PALs seems questionable at best,” O’Rielly recently tweeted. AT&T also questioned whether carriers will pursue PALs.

But there are signs of activity. In February, Federated Wireless, Google, Intel, Nokia, Qualcomm and Ruckus Wireless announced a "shared commitment to develop, market and promote solutions” using the 3.5 GHz, or Citizens Band Radio Service (CBRS) spectrum.

“The six companies aim to build a robust ecosystem of industry participants and make CBRS solutions as widely available as possible,” said a news release. “For example, private enterprises, venues and fixed operators could autonomously deploy high-quality in-building LTE networks into which all mobile network subscribers can roam. Operators could benefit from a significantly expanded footprint and capacity on new spectrum, while subscribers could enjoy a consistent wireless broadband experience -- particularly in challenging places such as indoor locations, venues and corporate campuses.”

“If people are worried about commercial interest in the band, that’s a good counterpart to it,” a former FCC aide said of the announcement by the six companies. If carriers don’t pursue PALs, “that would actually prove the sharing principles” showing operators now feel they can use unlicensed spectrum and don’t need exclusive licenses in the band, the former aide said.

Other former FCC officials were less optimistic. “The stingy licensing rules established for the PALs is at the heart of the problem,” said a former FCC spectrum official. “On top of that, three-year license terms and lack of renewal will make it just about impossible to attract the investment necessary to develop and deploy service.”

Federated Wireless Chief Technology Officer Kurt Schaubach said it’s no mystery why there's lots of interest in the 3.5 GHz band. The band “provides 150 megahertz of available spectrum usable for mobile and indoor wireless broadband services,” he said. “While the 3.5 GHz band will certainly be a viable option for mobile network operators, the potential industry benefits extend beyond to enterprises, critical infrastructure, and nontraditional service providers.”

The FCC is making progress on putting the spectrum in play, Schaubach said. “The FCC is already accepting applications for SAS and ESC administrators,” he said. “Additionally, as a result of the broad industry participation in the Wireless Innovation Forum, the standards and testing process for the ecosystem are nearly fully developed. We are hopeful that the FCC will complete formal testing of SAS and ESC technology later this year.”

“I think, realistically, we are still at least a year away from deployment,” said Harold Feld, senior vice president at Public Knowledge. “The first step is the development of the SAS databases, followed by development of chips that will utilize the frequencies. The design elements are not too hard, but no one could even begin the necessary work until the FCC settled on rules.”

Feld predicted early use will be experimental. The big question isn’t PALs vs. GAA, but whether exclusion zones will be further reduced to include significant population centers, he said: “We already had robust use” by wireless ISPs “of the 3.65 GHz band. It is easy to see the same users in the same territory wanting to expand their available spectrum for GAA use of the additional spectrum. But that is still a relatively small market. To reach the economies of scale to drive down equipment costs and push innovative uses, the biggest obstacle is finding a safe way to share with the military and eliminated the existing exclusion zones.”

“Clearly, mobile wireless, and uses that don’t require highly reliable throughput, are poised to take advantage of the new access to 3.5 GHz,” said Laura Stefani, wireless and technology lawyer at Fletcher Heald. “But I don’t see the band serving users who need a high-level of security and reliability, such as utilities, gas and oil pipelines, and wireless security systems.”

“Wi-Fi 802.11y has been able to use the 3.5 GHz band for many years, but there has been very little consumer interest in it because of the exclusion zones and other complications,” said Richard Bennett, free market blogger and network architect. Devices with 5G "will provide support for many frequency bands, including 3.5 GHz, by 2020. 3.5 GHz is a nice supplement to the common Wi-Fi bands, but it’s not a game changer.”