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The radio spectrum dedicated to transportation safety communications is under review by the FCC, which proposes to re-allocate some of the bandwidth to other uses. (NXP)

Industry group aims to end V2X tech dilemma, FCC bandwidth play

A proposed five-year trial could finally determine a V2X technology winner.

In a competing-technology conflict some have compared to Betamax vs. VHS but with life-and-death implications, the Alliance for Automotive Innovation (AAI) industry trade group proposed a solution this week to end industry discord over how best to execute vehicle-to-everything (V2X) safety communications. This followed an AAI proposal just days earlier intended to convince the Federal Communications Commission (FCC) to abandon a controversial plan to re-allocate a portion of the 5.9-GHz radio “Safety Spectrum” that for two decades has been reserved for transportation-related V2X communications.

The AAI – which is comprised of almost all major automakers as well as several electronics suppliers – said it has established a strategy that will allow the two “competing” V2X technologies, Dedicated Short-Range Communications (DSRC) and cellular radio-based V2X (C-V2X) to co-exist for five years in prescribed portions of the 75-megahertz range of the 5.9-GHz band reserved for the Safety Spectrum. Lack of industry consensus on which technology to deploy has been a significant factor in curtailing fitment of production vehicles with V2X capability and, many believe, also has restrained investment in the infrastructure required to exploit V2X’s potential.

“During the plan’s first five years, LTE C-V2X exclusively will operate in the band’s upper 20 MHz, DSRC exclusively will operate in the lower 20 MHz, and the remaining 30 MHz will be made available on a priority basis to Next-Gen DSRC and Advanced (5G) C-V2X applications as they are developed and deployed,” the AAI explained in a release. “After five years, a single technology will be selected to use the 5.9 GHz band going forward. That will also begin a ten-year phaseout period, during which the technology that does not prevail will phase out of its initial exclusive 20 MHz allocation in either the band’s upper or lower portion.”

Half the battle 
The 5.9-GHz band was first allocated to the Safety Spectrum in 1999. The first significant vehicle and infrastructure demonstrations could be considered to have happened at the ITS World Congress in Detroit in 2014. A proposed rulemaking from the administration of President Obama mandated fitment of V2X in passenger vehicles, but it was not pursued by the Trump administration in 2017. 

Against that backdrop, and despite limited deployments by brands such as Mercedes-Benz and GM’s Cadillac, the auto industry’s reticence to commit to either V2X technology was construed as the signal of disinterest that led the FCC to propose re-allocating the lower 60% of the Safety Spectrum. A December, 2019 news release confirming the Commission’s intention to ensure that the spectrum “supports its highest and best use for the American people,” added a scornful summary of its perspective on the situation: “For the past two decades, the entire 75 megahertz of spectrum in the 5.9 GHz band has been reserved for use by Dedicated Short-Range Communications (DSRC). However, after 20 years, DSRC still has not been widely deployed and this spectrum therefore generally remains unused.”

The AAI’s seeming solution to the V2X technology conundrum is a significant action in creating a clearer roadmap for V2X adoption, but the industry remains faced with the FCC’s proposal to re-allocate the lower 45 MHz of the spectrum – a move that many transportation interests insist will unduly squeeze V2X and seriously compromise its effectiveness for safety communications, including for automated-driving capabilities. Interference from broadband wifi Wi-Fi or other communications on the lower portion of the spectrum could render the V2X effectively “useless,” said John Kenney, director and senior principal researcher at Toyota InfoTech Labs, in January at SAE International’s Government/Industry Meeting in Washington, DC. It was a position that found considerable agreement among session participants.

A complimentary action
Just days before revealing its solution for the V2X technology conflict, the AAI announced its automaker members pledged to fit 5 million V2X radios in vehicles and on roadway infrastructure by 2025. But the deployment came with the stipulation of “the Federal Communications Commission (FCC) maintaining the entire 75 MHz within the 5.9 GHz Safety Spectrum for transportation safety and permitting Cellular V2X technology to operate alongside Dedicated Short Range Communication.”

In a written statement to SAE International reporters (and others), however, theThe FCC appeared unmoved by the AAI’s new V2X-deployment pledge. An FCC spokesperson said in an emailed statement to SAE International, “Given that about 17 million new vehicles have been sold in the United States in each of the last five years, this is not an impressive commitment. Instead, it only reinforces the need for the FCC to reform the use of the 5.9 GHz band so that it is put to its best use for the American people.”

Even before the FCC’s announcement of its intent to reexamine the use of the 5.9-GHz band, however, skeptics questioned the Commission’s stated guidance to industry regarding its expectations about V2X deployment and some believe, in the words of one source, that the FCC created “a self-fulfilling prophecy” regarding re-allocation of the lower 45 MHz of the spectrum. And many at the January SAE International conference said there has not been sufficient study of the potential for interference if the lower portion of the 75-MHz spectrum is allocated to broadband wifi Wi-Fi or other radio uses.

“The Alliance commitment directly addresses the FCC concern about insufficient deployment. Now, the FCC has a clear commitment from OEMs; road operators have made similar commitments,” said Michael Stelts, director, strategic standards & regulation,  –Panasonic R&D Company of America, one of AAI’s member companies. “The only thing holding industry back is the longstanding uncertainty about the V2X spectrum’s fate,” he added. “If the FCC were to accept these commitments, we can expect V2X to grow exponentially, providing us safer roadways.” At the time of this writing, the FCC had not responded to the AAI’s V2X technology-choice solution.

“Through the [5 million-radio] buildout commitment and this consensus band plan, the automotive industry has clearly demonstrated its dedication to ensuring that the safety, economic, and societal benefits of V2X technologies are made available in the United States,” said Auto Innovators President and CEO John Bozzella in a statement. “This band plan proposal, along with our members’ deployment commitment, clearly show that the industry is ready to move forward and optimize the use of the Safety Spectrum to enhance roadway safety.”

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