FCC moves closer to adopting new 3.5 GHz spectrum sharing rules

The FCC has promised to make more spectrum available for wireless services like Wi-Fi, and it appears well on its way to doing so in the 3.5 GHz band, along with adopting new sensing technologies to avoid interference for incumbent government radar users.

The commission on Friday announced a tentative agenda for its April 17 open meeting, where it's expected to consider a Citizens Broadband Radio Service Report and Order and Further Notice of Proposed Rulemaking that would add new spectrum sharing technologies to make 150 megahertz of contiguous spectrum available in the 3550-3700 MHz band for wireless broadband and other uses. The proceeding has been in the works for more than two years, with several rounds of public comment.

Under a new sharing scheme, the Report and Order will release more spectrum for consumer and industrial uses. The band is seen as ideal for small cells, but FCC staff also said it's possible new, as-yet-unforeseen uses for the band will emerge; hence, it's being referred to as the "innovation band."

In a blog post, FCC Chairman Tom Wheeler said the 3.5 GHz "provides an opportunity to try new innovations in spectrum licensing and access schemes to meet the needs of a multiplicity of users, simultaneously. And, crucially, we can do all this in a way that does not harm important federal missions."

The draft Report and Order describes a three-tiered sharing paradigm, whereby the lowest tier, dubbed General Authorized Access (GAA), is open to anyone with an FCC-certified device. At that level, it will cost nothing to access for commercial broadband users. At the Priority Access tier, users of the band can acquire--via auction--targeted, short-term licenses that provide interference protection from GAA users. At the top of the hierarchy are incumbent federal and commercial radar, satellite and other users that receive protection from all Citizen Broadband Service users, according to the chairman's blog.

The Spectrum Access System (SAS) takes an age-old role in spectrum management--the frequency coordinator--and updates it through the use of cloud computing, Wheeler said in the blog. "Long gone are the days of an engineer working with pencil and protractor (not to mention pocket protector) to coordinate users into a band," he said.

Interestingly, the FCC, National Telecommunications and Information Administration (NTIA) and Department of Defense (DoD) were able to work out a deal whereby the "exclusion" zones along the nation's coastlines are significantly smaller than they previously thought they needed to be in order to protect radar systems. The draft Report and Order provides a roadmap, recommended by NTIA and DoD, for operations along the coasts to use new sensing technologies.

Prior to the draft Report and Order, organizations continued to make their arguments for how the 3.5 GHz rules should be crafted. In a filing just last week, CTIA noted that Google (NASDAQ: GOOG), the National Cable & Telecommunications Association (NCTA), Federated Wireless and the Open Technology Institute/Public Knowledge (OTI/PK) were asking the FCC to effectively bar Long Term Evolution--Unlicensed (LTE-U) from the 3.5 GHz band. CTIA urged the FCC to reject their request and instead adopt rules that don't favor one technology over another.

T-Mobile US (NYSE:TMUS), for one, has said that it is exploring the use of Licensed Assisted Access (LAA) in, among others, the 3.5 GHz band.  

Federated Wireless, the technology startup led by former Sprint VP of Network Development Iyad Tarazi, argued in a recent filing that the commission should not permit the use of Licensed Assisted Access-LTE technology, which it referred to as "LAA-LTE," in the Citizens Band, saying the proposed standard cuts against the commission's mandate for technology neutrality by locking up the band, favoring incumbent carriers that can concatenate use of the Citizen's Band with their licensed spectrum, thereby dominating it and foreclosing use by competitive carriers and other GAA users that don't own spectrum.

According to a senior FCC staff official, the rules as written in the proposed order do not prohibit the use of LTE-U/LAA, and unlike the 5 GHz band, the 3.5 GHz band does not already have hundreds of millions of Wi-Fi users in it that carriers would need to work around.

For more:
- see the FCC blog and release
- see the NTIA's filing showing revised exclusion zones
- see this Wireless Week story

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