GM explains why it needs more time to test DSRC

Cadillac DSRC
When a V2V-equipped vehicle ahead is detected to be braking hard, 2017 Cadillac CTS drivers will get a "Hard Braking Ahead" alert, giving them extra time to react. Image: GM

General Motors executives paid a visit to FCC Chairman Ajit Pai’s office last week, providing an update on GM’s latest efforts to deploy Dedicated Short Range Communications (DSRC) for vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communications.

The upshot? GM, like a lot of carmakers, needs more time to ensure the safety of the technology—and they don’t want anybody (Wi-Fi, mainly) barging in on their spectrum. Auto makers have taken years to develop DSRC but have stepped up efforts to test and deploy the technology as others eye 5.9 GHz spectrum for unlicensed Wi-Fi use, which, of course, GM says could be very damaging to DSRC’s deployment and success.

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During the March 17 meeting, John Capp, director of Global Safety Strategy & Vehicle Programs, explained to the FCC chairman and his staff that while GM is leading the industry with the deployment of the DSRC-equipped 2017 Cadillac CTS, “this technology is no different than others in the fact that in order to further develop the safety benefits more testing must be done,” according to an ex parte filing.

GM is introducing the V2V system in the CTS performance sedan, beginning with 2017 interim model year cars that are now in production. V2V-equipped vehicles will share information that can be used to alert drivers to upcoming potential hazards. V2V is included as a standard feature on the 2017 CTS in the U.S. and Canada.

GM says the Cadillac's V2V solution, which uses DSRC and GPS, can handle 1,000 messages per second from vehicles up to nearly 1,000 feet away. By way of example, when a car approaches an urban intersection, the technology scans the vicinity for other vehicles and tracks their positions, directions and speeds, warning the driver of potential hazards that might otherwise be invisible. Only vehicles equipped with compatible V2V systems communicate with one another. 

RELATED: Automakers take aim at Qualcomm over DSRC-related proposals

Qualcomm, Broadcom and the NCTA say the 5.9 GHz band is the commission’s single best near-term opportunity to make additional unlicensed spectrum available for broadband services.

They've been pushing for a re-channelization approach they say is the best way to accomplish spectrum sharing in the 5.9 GHz band that would ensure protection for safety-critical, latency-sensitive DSRC services in the upper portion of the band and enable successful coexistence between the non-latency-sensitive DSRC and Wi-Fi devices in the lower portion of the band.

But the GM officials told the FCC that if the re-channelization proposal were to be chosen, there would need to be changes in both the software and hardware of the DSRC system, which would cause further delays. GM said it’s conducting additional testing and promised to provide the FCC with an update.