Bluetooth LE and UWB in Automotive Extend Capabilities at Lower System Cost

When contemplating all the automotive electronic goodies we can add it can be easy to forget that each new feature contributes to cost not only for the feature itself but also in communication between the feature and the larger system, demanding both transceivers and wiring to the central unit. Managing communication overhead has provided a major impetus for the switch to zonal architectures. A zonal structure can reduce the weight of wiring in a car from as much as 5km of wiring (at 100-120 pounds) down to 3km or less, which in turn reduces material cost and power consumption, while increasing range, all very desirable goals for automakers. Which prompts an obvious question – why not reduce cost and weight further through wireless connectivity, especially Bluetooth LE and UWB?

Bluetooth and UWB are the Obvious Starting Points

We already use Bluetooth (increasingly Bluetooth LE) to connect our phones to automotive audio system for music streaming and for phone calls. This technology has been refined in billions of devices across the dominant mobile OSes. Transceivers are compact and ultra-low power, and the standard continues to be enriched as the Bluetooth SIG addresses new and emerging use cases.

Connecting our phones for audio applications is one proof point but now we also see Bluetooth and UWB becoming prominent in automotive keyless entry. The Bluetooth SIG and the FiRa consortium (responsible for UWB) are now working closely to leverage complementary strengths in each protocol, Bluetooth LE for long to medium range raw proximity detection and UWB for centimeter-level accuracy and further security. This combination not only manages range versus accuracy tradeoffs; it also minimizes power consumption by using Bluetooth Low Energy (LE) through most of the range while only turning on UWB for short periods when close to the car. The lifetime of the battery in your key fob is proof enough that this combination is very power efficient.

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