Vehicle infotainment hotspots

Why it happens

Wireless phone projection turns every car into an access point. Apple’s guidance to carmakers is that the head unit hosts a Wi-Fi access point, preferably 802.11ac on 5 GHz¹, and that this link carries all audio and video for the session. Google lists 5 GHz Wi-Fi support² as a requirement for wireless Android Auto. Apple also tells carmakers that hidden networks are not recommended for CarPlay, so expect these networks to show up by name in a scan.

That access point never joins your channel plan. It picks its own channel and width, and a single 80 MHz channel spans four 20 MHz channels³. Airtime is shared among every network on the same spectrum. One carmaker’s service bulletin blames dropped projection sessions on crowded areas and tells technicians that only the traffic on the vehicle’s channel matters, not signal strength. On your floor the same rule runs the other way: the in-car link is a busy neighbor on whatever plant channel it overlaps.

Regulation narrows where the car can put that access point. In the EU, a 5 GHz access point installed in a road vehicle may use only 5150 to 5250 MHz, at 40 mW⁴, and the DFS ranges are not permitted in road vehicles. On the 5 GHz channel map, that block is channels 36 to 48: the same non-DFS channels you would keep control traffic on. In 6 GHz, both the FCC and the EU bar low-power indoor access points from vehicles. Very low power devices, capped at 14 dBm EIRP⁵, are outside both bars, so scan 6 GHz near the vehicles before you count it as clean.

NIST lists automobile hotspots alongside microwave ovens and phone hotspots as non-production emitters that can interfere with factory wireless. In an assembly plant the emitters are the product, so they gather where vehicles gather. You cannot change the head unit, so the fix is in your channel plan: know which channels the vehicles use and keep critical traffic off them.

How to confirm it

1. Walk the dock, yard, or test area with a WLAN scanner and a spectrum analyzer while vehicles are present, and list every network you do not own with its channel and width.
2. Check whether any of those networks overlap the primary or secondary channels of your access points in that area.
3. Compare retries and channel utilization on the affected access points with vehicle movements, shift by shift.
4. Repeat the scan with the vehicles gone. If the foreign networks and the retries leave together, you have found the cause.
5. Check which foreign networks remain when the vehicles are gone, so you do not confuse vehicles with fixed neighbors or personal hotspots.

Ben Rutter. "Vehicle infotainment hotspots." OT Wireless, published October 5, 2026. https://otwireless.com/causes/vehicle-infotainment-hotspots/

Rutter, B. (2026, October 5). Vehicle infotainment hotspots. OT Wireless. https://otwireless.com/causes/vehicle-infotainment-hotspots/

@misc{rutter2026vehicleinfotainmenthotspots,
  author = {Rutter, Ben},
  title = {{Vehicle infotainment hotspots}},
  year = {2026},
  howpublished = {\url{https://otwireless.com/causes/vehicle-infotainment-hotspots/}},
  organization = {OT Wireless},
}