Auto Service World
News   October 17, 2016   by Steve Pawlett

WI-FI Users Threaten V2V Spectrum


The U.S. auto industry is facing off against the cable television, cell phone and other Wi-Fi-dependent sectors in an effort to preserve the radio spectrum reserved for vehicle-to-vehicle (V2V) communications.

The Federal Communications Commission (FCC) allocated the 5.9 GHz Safety Spectrum band to dedicated short range communications (DSRC) in 1999 for the purpose of intelligent transportation systems (ITS). But with V2V automotive applications slow to develop, Wi-Fi users are demanding a piece of the V2V space.

In June, the FCC took the next step in a regulatory proceeding that has been germinating for a few years. It issued a proposed rule laying out two possible means for sharing the DSRC spectrum and announced a new three-phase testing program designed to determine whether interference with V2V communications can be abated when non-auto companies use the spectrum. The testing was to have begun in September and be finished by early 2017.

In terms of sharing the spectrum, the FCC is looking at two alternatives. The first is called “detect and avoid” which involves detecting the presence of DSRC signals and avoiding using the spectrum in the band when DSRC signals are present. The “re-channelization” approach involves splitting the DSRC spectrum into two contiguous blocks: the upper 30 MHz part of the band exclusively for safety-related communications, and permitting unlicensed devices to share the lower 45 MHz part of the band with non-safety DSRC communications.

Steven Bayless, vice president, technology and market, Intelligent Transportation Society of America, which isn’t opposed to sharing, says V2V applications will need the entire 75 MHz allocated by the commission.

“It cannot be chopped up and served a la carte based on arbitrary distinctions of safety vs. non-safety applications made by other parties with a goal of minimizing DSRC use of the band,” he says.

The auto industry and its suppliers back the detect and avoid option because it allows them to deploy the radio equipment they have been developing for years. Re-channelization would upend those efforts.

Auto industry partisans argue that detect and avoid will more likely protect DSRC from harmful interference and will not require any changes to DSRC’s system design or the FCC’s DSRC rules.

General Motors will be bringing DSRC technology to market this year in the model year 2017 Cadillac CTS. That DSRC technology would comply with the dictates of the new Federal Motor Vehicle Safety Standard (#150) the National Highway and Traffic Safety Administration is scheduled to propose imminently, according to GM. (An advanced notice of proposed rulemaking was issued two years ago).

Delphi is one of the suppliers for the Cadillac CTS. Delphi is ready to install its devices in the aftermarket as well, according to Joseph R. Dockemeyer Jr., technical fellow – Advanced RF Infrastructures and Services, Delphi Automotive.

The cable television and Wi-Fi industries argue that they need part of the DSRC 5.9 GHz band to advance next-generation Gigabit Wi-Fi. “It is the only band that can support this technology,” says Rick Chessen, senior vice president, Law & Regulatory Policy, National Cable and Telecommunications Association. Re-channelization will allow for that.

The potential threat to V2V communications is even more acute now given the FCC’s recent decision to allow more latitude for higher-powered, unlicensed U-NII devices in the U-NII-3 band. That 5850-5895 MHz band sits on the lower border of the 5.9 MHz band at issue. So interference with V2V applications is already a bigger threat than it was a year ago.

The Association of Global Automakers or the Alliance of Automobile Manufacturers had petitioned the FCC asking the agency to overturn its earlier decision to relax U-NII-3 out-of-band emission (OOBE) limits and revise it so it applied only to point-to-point U-NII-3 systems. But in March 2016, the FCC rejected that appeal.

The cable TV, mobile phone and other Wi-Fi sectors dwarf, in terms of users, the automotive V2V sector. So the former clearly have a leg up in terms of their economic justification and, most importantly, political punch in Washington. Comments made by FCC commissioners seem to indicate a preference for re-channelization. If the FCC goes that route, it could pose problems for any meshing with the NHTSA’s soon-to-be proposed FMVSS 150.


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