7/7 - Public Interest FCC Comments on Wi-Fi Sharing of 5.9 GHz Auto Industry Spectrum

Regulatory/Legislative Filings
July 7, 2016

On July 7, OTI submitted FCC comments on Wi-fi sharing of 5.9 Ghz spectrum with the auto industry. Read the full comments here. 


The undersigned members of the Public Interest Spectrum Coalition (hereinafter the “Public Interest Organizations,” or “PIOs”) strongly supported the Commission’s 2013 proposal to expand unlicensed public access to 775 contiguous megahertz across the 5 GHz band, thereby enabling gigabit-fast and more affordable Wi-Fi connectivity made possible by the existing 802.11ac Wi-Fi standard. The beneficial and mushrooming impact of unlicensed spectrum on the availability and affordability of mobile Internet access – and on the telecom sector and the U.S. economy more generally – is well documented. Wi-Fi is the workhorse of the Internet that currently carries an average 80 percent of all mobile device data traffic – and does so in an Public Notice, Revision of Part 15 of the Commission’s Rules to Permit Unlicensed National Information Infrastructure (U-NII) Devices in the 5 GHz Band, ET Docket No. 13-49 (rel. June 1, 2016) (“Public Notice”). incredibly democratic and efficient manner through end-user networks and small cell spectrum re-use. Expanding unlicensed and wider-channel access to frequencies above 5 GHz can complement the use of licensed spectrum and facilitate new market entrants, services and applications that rely solely on unlicensed.

First, we strongly support opening the 5850-5925 MHz (U-NII-4) band for shared and unlicensed use, subject only to necessary interference protections for band incumbents. Contiguous unlicensed access to at least the lower 40 megahertz of U-NII-4 band, combined with technical rules harmonized with the U-NII-3 band, will enable access to 80 and 160 megahertz channels which can greatly amplify the potential increases in capacity for Wi-Fi operations. Accordingly, the Public Interest Organizations urge the Commission to lead and expedite a collaborative testing process aimed at a win-win compromise that doubly benefits nearly all Americans by enabling two services – DSRC and U-NII devices – to coexist and share at least the lower portion of the 5.9 GHz band without risk of harmful interference to truly delay- sensitive safety-of-life V2V or V2I communications.

Second, the Public Interest Organizations believe that the re-channelization approach to sharing strikes the best balance between DOT’s legitimate interest in promoting crash avoidance and the Commission’s interest in promoting ubiquitous broadband connectivity and innovation. Since both DSRC safety-of-life applications and expanded broadband capacity can deliver important benefits for virtually all Americans, the Commission should strive to enable both of these compelling public interest outcomes.

The critical factor in striking this balance is the distinction between real-time safety and other non-safety (or non-time-critical) DSRC applications. By dedicating three channels exclusively to DSRC safety applications – including the dedicated 10 megahertz BSM channel needed to implement DOT’s proposed V2V mandate – the Qualcomm proposal virtually eliminates the risk of interference with safety-of-life applications, while at the same time adhering to the FCC’s evolving principles of spectrum efficiency and flexibility that require public safety allocations to be narrowly defined and “limited” to “the amount of spectrum . . . which ensures that those [compelling public interest] objectives are achieved.” Our groups generally support proposals to re-channelize the band so that V2V Basic Safety Messaging and other latency-sensitive safety-of-life DSRC applications will have two or three dedicated safety channels (20 or 30 megahertz) at the top of the ITS band, furthest away from any potential interference from unlicensed operations in U-NII-3 and in the bottom 40 megahertz of U-NII-4.

The Public Interest Organizations urge the Commission to reject the detect-and-avoid approach outlined in the Public Notice. The fundamental problem with the Cisco approach, as currently described, is that it would not permit the economically feasible deployment of unlicensed technologies, particularly Wi-Fi. Vacating the entire band if any DSRC transmission is detected on any channel across a 100 megahertz range (the entire 5.9 GHz band and the adjacent 5825-5850 MHz) is an extreme restriction that may effectively exclude 802.11ac Wi-Fi and future unlicensed innovation from the band. Since a V2V mandate would require that vehicles use the BSM safety channel to constantly communicate their location, heading, speed and other data to surrounding vehicles, the continual and ubiquitous traffic on this single 10 MHz channel could exclude unlicensed devices from the entire 5.9 GHz band, with the exception of those inside well-shielded buildings and away from streets and vehicles. The Cisco detect-and- avoid approach would make unlicensed devices substantially more expensive and restrict the benefits of extended gigabit Wi-Fi connectivity to indoor enterprise Wi-Fi systems (such as hotels, convention center, corporate campuses), while denying those benefits to individual households and other business establishments located close to streets and vehicles.

Third, the Public Interest Organizations strongly agree with Commissioner O’Rielly and others that non-safety of life commercial and informational DSRC applications should share at least the lower portion of the band on an equal basis with unlicensed operators. The Commission’s 1999 ITS allocation order contemplated, and reserved for later judgment, that non-safety functions could operate on an unlicensed basis separate from the safety-of-life DSRC. And certainly after more than 15 years of leaving the band fallow, even the speculative non- safety applications suggested by the auto industry (such as advertising, social media, navigation, in-vehicle displays and electronic payments) have been or soon will be subsumed by more efficient general purpose cellular and Wi-Fi networks –including the high-capacity and low- latency benefits of general purpose 5G networks – at least a decade before NHTSA expects DSRC to achieve a critical adoption rate sometime in the 2030s.

Fourth, and relatedly, the fundamental framework of FCC spectrum allocation policy has evolved since 1999 in a manner that completely contradicts auto industry pleas for an auction-free and effectively exclusive silo of special-purpose spectrum with a designated technology (DSRC) that will be obsolete (if it isn’t already) long before the 20-to-30-year deployment period NHTSA estimates is needed even before it can judge whether DSRC is effective for crash avoidance. Leaving most of the band’s capacity essentially fallow for the indefinite future is distinctly inconsistent with FCC spectrum management principles adopted in the years since the original 1999 ITS allocation. It also runs counter to the Obama Administration’s historic initiative to open underutilized bands for sharing to the greatest extent feasible.

The Commission’s effort since 1999 to move away from silos of special-purpose use and toward more intensively-used and flexible general-purpose use makes the distinction between DSRC’s anticipated real-time safety and non-safety applications critical. In 2002 the Spectrum Policy Task Force (SPTF) Report recommended that the Commission “eschew command-and-control regulation” of spectrum use. The Task Force Report emphasized that exceptions made for public safety or other public interest allocations should be narrowly defined “and the amount of spectrum . . . limited to that which ensures that those [compelling public interest] objectives are achieved.” Embracing this trend, the 2010 National Broadband Plan criticized the traditional approach to allocating spectrum “on a band-by-band, service-by-service basis, typically in response to specific requests for service allocations” and concluded that “the failure to revisit historical allocations can leave spectrum handcuffed to particular use cases and outmoded services, and less valuable and less transferable to innovators who seek to use it for new services.”

Finally, the auto industry’s recent Petition for Reconsideration challenging the out of band emission (OOBE) limits adopted by the Commission for unlicensed use of the adjacent U-NII-3 band reinforces just how easily the interference concerns of the auto industry could be addressed through re-channelization. By re-channelizing to physically separate the real-time life-and-safety channels from unlicensed OOBE, the automakers’ concern about interference to BSMs can be completely satisfied, removing virtually all risk of interference between future Wi-Fi and V2V safety signaling. This can be done without undue delay since there are no DSRC deployments and DOT is expected to give automakers a multi-year transition period before requiring the installation of at least a single-radio DSRC system in every new car sold.

You can download the full comments below: 

Public Interest FCC Comments on Wi-Fi Sharing of 5.9 GHz Auto Industry Spectrum