AT&T, T-Mobile butt heads with Comcast, Wi-Fi in 5.9 GHz melee

DSRC
Auto makers want the FCC to maintain the entire 75 MHz of spectrum in the 5.9 GHz band for Intelligent Transportation Systems (ITS). (U.S. Department of Transportation)

The 5.9 GHz band, aka “the mess,” is at the center of several fights as the FCC considers rejiggering the band for Wi-Fi after years of the spectrum laying mostly fallow.

The FCC voted last year to advance a proposal that would reallocate large portions of the 5.9 GHz band, dedicating spectrum to both unlicensed and C-V2X technologies. The FCC’s Notice of Proposed Rulemaking (NPRM) would make the lower 45 MHz (5.85-5.895 GHz) available for unlicensed use, which Chairman Ajit Pai said will “fully realize Wi-Fi’s potential.” Reply comments came due Monday, triggering the latest round of arguments.

Last week, the FCC adopted a plan to make 1,200 megahertz of 6 GHz spectrum, which is next door to the 5.9 band, available for unlicensed use. That was considered a watershed moment for the Wi-Fi industry, and while that was a complicated proceeding, the 5.9 GHz band has been described as even more so.

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RELATED: Editor’s Corner—6 GHz looks far more promising these days than 5.9 GHz

In this latest round, the Alliance for Automotive Innovation filed comments urging the FCC to back off its plans for using the 5.9 GHz for unlicensed uses, pointing to Wi-Fi’s win in the 6 GHz band as one reason to do so. The alliance wants the entire 75 megahertz available for automotive purposes, and it suggests that for a period of five years, the industry should study DSRC and C-V2X, after which it will decide which technology will be permitted to use the band.

“After a single technology is selected, a ten-year phaseout period will ensue, whereby the technology that does not prevail will retain its initial exclusive 20 MHz allocation in either the upper or lower portion of the band,” the Alliance told the commission in its filing (PDF). “After this ten-year phaseout, the chosen technology will have full access to all 75 MHz of the 5.9 GHz band.”

WifiForward, which represents the likes of Comcast, Charter Communications and other Wi-Fi stakeholders, said “no way” to that.

“We cannot wait another 20 years to put these unused airwaves to work and it's concerning that some are continuing to drag their feet,” the organization said. “The proposed plan calls for further delays, giving the auto industry another 5 years just to think about which auto safety technology they like best, an indefinite period subject to an uncertain process to actually choose between DSRC and CV2X, and then another 10 years to phase-out whichever technology is not preferred. American broadband and automotive consumers deserve better. The FCC’s work to modernize the 5.9 GHz band is part of the ongoing commitment to next-generation Wi-Fi 6 and 5G connectivity and this spectrum is a vital piece of the puzzle.”

A group of public interest organizations – including New America’s Open Technology Institute (OTI), the American Library Association, the Benton Foundation, Next Century Cities and Public Knowledge – suggests (PDF) it would be a good idea to relocate Intelligent Transportation Systems (ITS) operations to a different, potentially better band to ensure that both Wi-Fi and other unlicensed services and auto safety systems have the spectrum they need to optimize consumer welfare. The 4.9 GHz band, where 50 megahertz of “grossly underutilized spectrum” already is allocated exclusively for public safety, should be a prime candidate for the new ITS band, according to the group.  

“The work-and-learn-from-home crisis has amplified the urgency of boosting capacity for Wi-Fi,” said Michael Calabrese, director of the OTI’s Wireless Future Project, in a statement. “The gigabit-fast Wi-Fi channel the Commission can create by reallocating the lower portion of the virtually unused 5.9 GHz band is high priority because it can be used immediately with existing gear and provides better coverage than any 6 GHz channel for both homes and rural broadband. The STAs the FCC recently granted to WISPs to use that 45 megahertz right now is a proof of concept. We believe all five commissioners are committed to moving this proceeding to a close as rapidly as possible.”

RELATED: FCC gives WISPs access to 5.9 GHz for COVID-19 response

In its filing (PDF), Comcast told the commission that it’s on the right path in allocating more unlicensed spectrum for the nation’s connectivity needs. The demand for Wi-Fi calling has increased dramatically as a result of the COVID-19 pandemic, indicating that mobile networks will continue to rely on unlicensed spectrum. Comcast also noted that Wi-Fi calling minutes on AT&T’s network have increased 76% over average levels, and Comcast’s own Xfinity Mobile has seen a 49% increase in Wi-Fi offloading from its mobile devices compared to levels on March 1.

Comcast reiterated that the overwhelming majority of customers connect to its broadband network using a Wi-Fi connection, and access to more unlicensed spectrum is critical to allow consumers to access the full speeds and capacity of wireline networks and alleviate the threat of a Wi-Fi bottleneck.

T-Mobile, AT&T weigh in

On the flip side, T-Mobile is urging the FCC to make the entire 5.850-5.925 GHz band available for licensed cellular Vehicle to Everything (C-V2X) technologies. It also suggests that because a significant amount of spectrum soon will be made available for unlicensed use via the 6 GHz band, there’s no need to reserve a portion of the 5.9 GHz band for unlicensed operations.

“Commenters agree that in order to ensure the success of C-V2X, the Commission should not split any spectrum in the 5.9 GHz band designated for Intelligent Transportation Systems (ITS) between C-V2X and Dedicated Short Range Communications (DSRC) technologies,” T-Mobile stated in its filing (PDF). “In fact, the Commission should reject calls to reserve any portion of the 5.9 GHz band for DSRC.”

There’s been an ongoing fight between auto makers – some of them want to stick with DSRC and others are clearly for C-V2X – and the cellular industry as to whether DSRC should even continue as a technology. Some say DSRC had its chance – over 20 years – to make a case for itself, and little happened until C-V2X started eyeing the spectrum. C-V2X is a newer technology, and the thinking on the part of its advocates is it’s more future-forward.

RELATED: Israeli startup Autotalks launches global V2X chipset with DSRC, C-V2X

Reallocating C-V2X to a different band outside the 5.9 GHz range is “simply infeasible,” according to T-Mobile. “The commission should therefore preserve the 5.9 GHz band for automotive applications and reevaluate its proposal to allocate spectrum in the band for unlicensed operations.”

AT&T agreed on that score, saying commenters in the docket “overwhelmingly” oppose the reallocation of the lower 45 MHz of the 5.9 GHz band to unlicensed operation because Wi-Fi is not its best and most efficient use.

AT&T also said that while MVNOs, which lack network facilities, may have a vested interest in offloading as much data traffic as possible to Wi-Fi networks, that is often not the case for facilities-based mobile network operators (MNOs). “In the last decade, facilities-based MNOs, which handle the vast majority of data traffic, have increased their spectrum inventories, densified their LTE and LTE-Advanced networks and begun deploying 5G networks, dispelling the notion that facilities-based MNOs want or need to significantly rely on Wi-Fi offload,” the operator told the commission (PDF).

FCC Commissioners Michael O’Rielly and Jessica Rosenworcel were early advocates of taking a fresh look at the 5.9 GHz band for unlicensed purposes. O’Rielly regularly defers to the chairman when it comes to the timing of agenda items, but he sounded optimistic in a tweet this week, saying “there should be no doubt” that reallocating the 5.9 GHz band will generate great benefits for American consumers and the broader unlicensed community. “Let’s get this done this summer,” he said.

 

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