DSRC, Some V2X Not Viable Under FCC 5.9 GHz Rules, ITS America Hears

ITS America is pushing the FCC to drop plans to change how the 5.9 GHz band is allocated, as a working group released a plan Wednesday on how industry can use the 30 GHz still allocated to intelligent transportation systems, officials said during a webinar Wednesday. They cautioned that the 30 MHz will be usable only if it is protected from Wi-Fi in the other 45 MHz of the band and said some technologies are no longer viable.

The FCC changed the allocation 5-0 in November, despite concerns by the Department of Transportation and groups including ITS America (see 2011180043). Acting FCC Chairwoman Jessica Rosenworcel has advocated allowing unlicensed use of the band. The commission declined comment now.

“ITS America strongly believes that we should have 75 MHz for [vehicle-to-everything (V2X)] because in the future, that bandwidth will be needed to meet the demands of all the vehicles and all the traffic in that spectrum,” said President Shailen Bhatt. ITS America has “great concerns” that the 30 MHz left for V2X “is not properly shielded and that other band emissions will likely interfere with safety-critical messages,” he said. “We are continuing the fight for the full 75.”

All the votes in favor of moving forward on reallocation have been unanimous, said Tim Drake, ITS America vice president-public policy and regulatory affairs. Drake said adding another Democrat to the FCC may not make a difference but does provide an opportunity to reopen the discussion. “Similar to how eager we are in the transportation area to protect this spectrum … there are interests on the other side who are very eager to open it up for unlicensed device use,” he said: “The main scope of the landscape has not shifted significantly.”

ITS America formed a working group to look at what’s practical if the FCC rules stand, which released conclusions during the webinar. The order hasn't been published in the Federal Register. The group found in its early analysis that more than 20 V2X applications won’t be possible in 30 GHz, Drake said.

Those apps include intersection and highway/railroad collision warnings, work zone alerts, wrong-way driver warnings, emergency electronic brake lights and stop sign violation warnings, according to a list posted during the webinar. The kind of messages no longer possible “are important for automated vehicles, for sharing developed from other sensors within a vehicle,” Drake said.

Dedicated short-range communications, the original use for the band, is unlikely in 30 MHz, said Mark Knellinger, Cisco transportation solutions architect. DRSC uses “75 MHz, control and service channels,” he said: “There will be no way to deploy in the remaining 30 MHz.”

The FCC and DOT are unlikely to hand down rules on how the 30 GHz can or can’t be used, said John Kenney, Toyota InfoTechnology Center director-networking research. “We’re not talking about legal prohibitions; instead we’re talking about developing an industry consensus,” he said: “We’re going to need more technical work.” Packing messages into a channel is like packing eggs, “which are fragile, into a suitcase,” he said: “Resist the temptation to overpack.”