What’s the deal with Ultra Wideband?

5 min reading time
BMW will use Ultra Wideband technology in the BMW iX to power the BMW Digital Key Plus. Overall, UWB technology is set to become very handy for car owners everywhere, promising both increased security and added ease when using car keys. But what is Ultra Wideband and how does it work? Read on as we explain what potential UWB technology has, and how it helps launch the BMW Digital Key Plus.

11 March 2021

What is Ultra Wideband technology?

Ultra Wideband is a short-range, wireless communication protocol that uses radio waves, just like Bluetooth or Wi-Fi. However, it drastically improves both the application possibilities, and security levels from similar radio technologies. The technology is not new as such, and is today used mostly for advanced medical devices and other professional use. But thanks to its recent addition to regular everyday devices like mobile phones and not least cars, it will now become more broadly available for end users. Uses vary but car owners will benefit primarily thanks to UWB’s highly accurate and precise localization capabilities. 

This is because Ultra Wideband allows for high-precision localization at distances typically up to 20 meters. When combining multiple UWB radios into a single network, UWB technology can as such be used to identify the exact position of mobile UWB-equipped consumer devices in the immediate vicinity. 

The technology is becoming more widespread, and the latest smartphones have already incorporated chips with UWB into their design, right next to the better-known technologies like Wi-Fi and Bluetooth.

How does Ultra Wideband technology work?

Ultra Wideband technology makes use of a very high bandwidth of 499.2MHz. In comparison, Wi-Fi only uses about 20 to 160MHz of bandwidth, and Bluetooth as little as 80Mhz. While other radio technologies split the available bandwidth into smaller chunks in favor of higher data rates or using multiple data channels at the same time, UWB dedicates the entire available bandwidth to the transmission of very short radio wave pulses. The pulse duration of UWB of only two nanoseconds is only a fraction of the pulse durations being used for data transmission in other wireless radio applications. Since radio waves propagate at the speed of light, keeping the pulse duration as short as possible is key to calculate the actual distance accurately. And as only very few UWB pulses are needed for an accurate measurement, UWB radios can be used to almost instantly provide localization information or perform real-time live tracking of moving objects, without suffering the drawbacks of long latencies. 

Additionally, the most recent generation of UWB radios cryptographically encode radio pulses so that a maximum allowed physical distance between UWB radios is guaranteed during wireless communication. Since UWB radios effectively measure the time a radio wave is traveling from a sender to a receiver, UWB radio signals cannot be recorded and relayed over, for example, the internet connection of a UWB-equipped smartphone to a remotely located hacker without being detected.

What will Ultra Wideband technology mean for me and my car?

The biggest promise UWB tech holds for car owners is in the area of precision localization of car keys. As cars become fitted with UWB antennas, they will be able to recognize other UWB-equipped devices – like a digital key installed on your phone in your pocket – instantly and precisely. Your car will be able to recognize when you are getting closer and automatically unlock, turn on its lights, or even launch preconfigured personalized settings.

UWB technology also puts an end to relay attacks, even if car keys are in motion while being carried. The reason for this is that the UWB chip is always measuring the distance of a straight line between the car key and the car (measuring the speed of light), and consequently preventing the car’s engine from starting if the car key isn’t physically within the vehicle.

Introducing the BMW Digital Key Plus

Starting with the BMW iX and the new optional BMW Digital Key Plus, BMW drivers will be able to get their hands on a Digital Key equipped with Ultra Wideband for the very first time. 

When using the BMW Digital Key Plus, the BMW iX will greet you by turning on its lights when you approach the car and unlock shortly before you reach the door handle, without you ever taking your smartphone out of your pocket. To do this, the UWB technology will “range” with your phone and automatically recognize the device’s distance from the vehicle, then initiate the desired actions. And, even more conveniently, you will be able to start your engine without having to physically place your phone in the smartphone tray. Simply enter the vehicle, and its UWB chips will detect that you are a keyholder located in the car – and push start. It doesn’t get easier than that.

While you drive, the wireless charging tray can charge your smartphone wirelessly. And if your smartphone runs low on battery, you can still unlock your BMW iX by holding your smartphone to the door handle using NFC technology.*

*Please note: Availability of low power mode depends on the smartphone model.

An industry standard for the BMW Digital Key brings Ultra Wideband technology into the mass market

BMW is invested in the work behind a sustainable ecosystem for the Digital Key, and is actively supporting the development of industry-wide standards. To achieve this, BMW engineers and developers are highly involved in the Car Connectivity Consortium initiative, which aims to build a worldwide industry-leading Digital Key standard and certification programme. In 2018 the Car Connectivity Consortium publicly announced to be working on UWB as the ideal future technology to enable the Digital Key for passive, location-aware keyless access, providing security and outstanding user experience.

Following that announcement, UWB has emerged from an industrial technology to mass-market technology, growing to be an industry-wide standardized ecosystem. 

For every-day users, an industry standard will bring along countless benefits: most pressing of all is the smart integration of soft- and hardware for long-term solutions that benefit everyday drivers, in line with their growing demands for truly helpful digital mobility solutions.

Photos: BMW; Author: David Barnwell; Animation: Chris Faber