I broached the subject with Drue Freeman, vice president, global sales and marketing, automotive business unit, NXP Semiconductors, who was also a presenter at the European Microelectronics Summit. Freeman told me, "You need to understand that car keys must last longer than cars."
Indeed, that's the first hurdle for any attempt to use a smartphone as a car key. Consumers swap smartphones roughly every 1.5 years. The average car lasts more than eight years.
While acknowledging that opening a car with an NFC-enabled smartphone could be done, Freeman posed a more salient matter of convenience.
In the current generation of keyless entry for cars, a smart key system disengages the immobilizer and activates the ignition without inserting a key in the ignition. The system uses LF (low frequency, 125 kHz) and RF (radio frequency, >300 MHz). It works by having a series of LF transmitting antennas both inside and outside the vehicle. External antennas are in the door handles. When the vehicle is triggered, an LF signal is transmitted from the antennas to the key. The key activates if it is sufficiently close, and it transmits its ID back to the vehicle via RF to a receiver located in the vehicle.
Applying NFC in a smartphone to the car security system is certainly feasible. But the driver still needs to walk up to a car and physically open the door -- unless the smartphone is also integrated with an LF/RF-based keyless entry system.
Freeman explained, "With a smartphone, it's a two-step process. In contrast, the smart car key you use today can remotely flip a car open -- instantly," without fiddling with your smartphone first.
But let's be clear: The idea of unlocking and locking the car and then starting the ignition with a phone has haunted the minds of some carmakers, such as Hyundai.
By using NFC, Hyundai demonstrated "Connectivity Concept."
By using an embedded NFC tag in the car, Hyundai has designed a system that allows owners to unlock a vehicle, start the engine, and link up to the touchscreen with a quick swipe. The Korean automaker showed earlier this year what the company calls its "Connectivity Concept" in a demonstration i30 hatchback car.
So, the idea of smartphone as your car key has been percolating for a few years, and it has gotten some attention from carmakers. Can a Bluetooth LE be that key?
One might say: Why not?
The first step in proving the feasibility of this concept is to make sure there is absolutely no EMC interference between a Bluetooth-based smart car key and the electronics inside the vehicle. Perhaps more important, Bluetooth LE requires power (albeit low energy). NFC connectivity "does not require a power supply in the key, hence does not affect the key's battery lifetime," according to NXP's spokesperson. "Setting up a connectivity link is done by a touch and would not require an exchange pairing credential upfront." In sum, NFC allows carmakers to focus on convenience and security.
Even assuming that either wireless technology -- NFC or Bluetooth -- works fine as a smart car key, technology suppliers need to clear one more hurdle.
NXP's Freeman explained that for a carmaker, the branded car key establishes the first and the most significant physical and tactile contact with car owners. Automotive companies might not be so eager to give up that precious branding opportunity to a smartphone -- which bears no automotive brand.
For the time being, the NFC vs. Bluetooth LE battleground is likely to be focused more on connecting a smart car key with a smartphone (or any wearable smart device), rather than a smartphone replacing a car key.
According to NXP, the company's multi-function car key using NFC is "one member of a complete new product family designed for Smart Access solutions." The product family debuts in the market with model year '13 vehicles.