Ford warns against WiFi interference in talking cars

Promising technology that aims to prevent cars from crashing would be "severely impaired" by interference from a WiFi hotspot, says Ford Motor Co., which is urging the Federal Communications Commission not to reallocate a chunk of radio spectrum reserved for vehicle safety.

Why it matters: Interference from a WiFi signal that might keep children occupied with video games in the back seat could potentially delay the delivery of a basic safety message to their parent's car at precisely the moment it's needed.

The big picture: In order to meet growing demand for WiFi service, the FCC wants to reallocate a portion of the 5.9 GHz band set aside in 1999 for vehicle-to-vehicle (V2V) communication.

• Its proposal would take 45 of the 75 MHz frequencies of so-called "safety spectrum" for WiFi, leaving 30 MHz for connected cars.
• That 30 MHz would be further divided between an older V2V technology called dedicated short range communication (DSRC) that a few automakers are using, and newer cellular vehicle-to-everything (C-V2X), which Ford and others support.

What's happening: In comments filed Monday on the FCC's proposed rule-making, Ford included test results of real-world scenarios to argue against the spectrum-sharing.

• Ford selected an accident-prone intersection in Ann Arbor, Michigan, and then ran field and lab tests to show what effect a WiFi device operating on the contested frequencies would have on the car's ability to receive safety-critical messages.

What they found: WiFi interference caused an "unacceptable outage of critical basic safety message communications preventing the C-V2X system from performing as intended."

• "The fact of the matter is there’s just a lot of leakage outside the bands they’re operating in," Don Butler, Ford's executive director for connected vehicles and services, told reporters.
• Ford said the FCC should also ensure there's enough buffer in the spectrum to support future autonomous vehicles and to eventually transition to 5G technology.

Editor's note: This piece was clarified to reflect that all of the 5.9 GHz band is in use for auto safety.