Industry Groups Weigh in on FCC’s 5.9 GHz ITS Proposal
Saturday, March 14, 2020 | Comments

Public-safety and other industry groups told the FCC how important the 5.9 GHz band is for many traffic and public-safety related applications and to reconsider allowing unlicensed operation in the band.

The 5.9 GHz band encompasses 75 megahertz of spectrum allocated for the intelligent transportation system (ITS) using dedicated short range communications (DSRC) technology. The commission proposed diverting the lower 45 megahertz of the band from 5.85 – 5.895 GHz to unlicensed operation and maintain the remaining 30 megahertz of spectrum at 5.895 – 5.925 MHz for ITS. The FCC also proposed making 20 megahertz of the resulting ITS spectrum for cellular-vehicle-to-everything (C-V2X) technology, with the remaining 10 megahertz to be decided for either DSRC or C-V2X technologies.

The National Public Safety Telecommunications Council (NPSTC) said it does not support the reallocation of the 45 megahertz for unlicensed operation. However, if the commission chooses to allow unlicensed operation in the 5.9 GHz band, NPSTC said it should consider the proposals and actions concurrently in both the 5.9 GHz and the 6 GHz bands when defining the rules.

The FCC also proposed unlicensed operations at 6 GHz in 2018.

“NPSTC believes that in aggregate, the commission is on a path that will result in an overabundance of spectrum for unlicensed devices, at the expense of mission-critical operations that require spectrum to ensure safety, reliability and efficiency,” the group said in its comments.

NPSTC said diverting the 5.9 GHz spectrum could negatively impact the ITS, and in particular, the recently announced U.S. Department of Transportation (DOT) program designed to help avoid traffic accidents and save the lives of first responders rushing to aid in emergencies.

However, if the FCC chooses to allow unlicensed operation in the 5.9 GHz band, it should consider the proposals and actions concurrently in both the 5.9 and 6 GHz bands when defining the rules, NPSTC said.

“… Any unlicensed devices that share spectrum at 6 GHz where critical fixed links operate must have rigorous automatic frequency coordination (AFC),” NPSTC said. “In contrast, the commission has proposed separate band segments for unlicensed and ITS operations at 5.9 GHz. Therefore, low power indoor operations without AFC potentially are a better fit at 5.9 GHz than at 6 GHz. Failure to consider proposals and actions for both bands concurrently may not reveal such potential opportunities.”

In separate comments, the Traffic Safety Committee of the National Sheriffs’ Association (NSA) supported keeping the 5.9 GHz band dedicated to transportation safety. “A very real concern is that proposed efforts to split that band among transportation safety and other Wi-Fi uses could negate the ability for safety systems to be widely implemented as technology evolves,” the NSA comments said.

With increased and improved technology, law enforcement will be increasingly dependent on the ability to communicate over frequencies in the 5.9 GHz band with an ever-increasing number of devices to operate safely in an environment with other vehicles. With the existing system of a completely dedicated band, there will be significant enhancements in road safety to decrease vehicle collisions, vehicle-pedestrian crashes and save lives, NSA said.

“As proposed, the band split would happen without any testing that safety systems would not be impacted by interference,” NSA said in its comments. “We also understand that ongoing development of safety systems that are yielding promising innovations would likely be interrupted. We would encourage the federal government to not move to a new approach without giving consideration to issues that could and probably will delay or eliminate implementation of safety enhancements.”

The Government Wireless Technology & Communications Association (GWTCA) said vehicle-to-everything (V2X) technologies are a vital tool in national transportation safety and helping to reduce these costs. “Allowing untested technologies and unlicensed devices to use the spectrum available for V2X technologies could negate the ability of these technologies to function,” the group said.

Numerous issues that law enforcement and fire personnel face, such as speeding, can be assisted by V2X technologies. Further, V2X technologies can support traffic signal prioritization or pre-emption through channel 184. “As a result, implementation of the commission’s proposal would require new testing and migration to CV2X, eliminating interoperability with the control channel at 172 if channel 184 were to remain as a DSRC 802.11p technology channel,” GWTCA said.

For V2X communications to work safely, the messages must travel fast and without interference. For example, a delay in a vehicle receiving a crash-avoidance message because of signal interference can mean the difference between a crash and a close call. Expert analysis has determined that the reduction in spectrum available for V2X suggested by the FCC does not leave enough spectrum for V2X technologies and would likely cause significant interference with V2X technologies operating in the remaining 30 megahertz of spectrum. Analysis by the DOT determined that such an increase in signal interference could render the remaining 30 megahertz useless for V2X collision-avoidance applications, GWTCA’s comments said.

AT&T joined the proponents of keeping the 5.9 GHz spectrum reserved for ITS, saying the public interest would be best served by allowing continued use of the full 75 megahertz for ITS and continued testing of shared- se of the band between ITS and unlicensed devices.

“Though development and deployment of DSRC applications in the 5.9 GHz band has been slow, it is premature to reallocate any (much less the majority) of the band to exclusively unlicensed use or to completely abandon a proven and tested DSRC technology in favor of less-tested cellular-vehicle to everything (C-V2X) technology,” AT&T said in its comments.

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