How do UWB car digital keys work?

The so-called keyless or keyless systems for the car are practical, but not unanimous. Current security solutions, which make a conventional car key superfluous, can be frustrating. Many high-end car owners who are victims of theft can attest to this. With so-called Ultrawideband (UWB) technology, more and more carmakers want to end the actions of criminals. In this article you will find out how it works with a BMW 220i and an iPhone and why UWB has the potential to revolutionize the connected home market.

Keyless systems ensure that the car opens automatically as soon as its owner approaches, without having to hold the key in his hand or press any key on the key. It is also possible to start the engine by pressing a button, without having to turn on the ignition. With current systems, however, comfort comes at the expense of security, as it is possible to overcome them with a little technical knowledge or a reasonable economic investment.

If the user approaches the car with their iPhone in their pocket, the door opens automatically. If you pay attention, you will be able to hear the unlock just before you pull the door handle. / © Alexander Hauk

With the traditional keyless technique, the system actually measures the reception level of the key radio signal, without checking whether the measured reception level makes sense. Sometimes the signal level just needs to be high enough for the car doors to unlock.

Criminals use this weakness with the help of special devices. They amplify and amplify the radio signal of the key, which for example is hung by its rightful owner on the keyboard board behind its own front door or placed on a restaurant table.

Several car manufacturers rely on UWB

The so-called relay attack, as described above, does not work with ultra broadband technology. In fact, the system not only measures the signal level, but also, thanks to UWB, the duration of the radio signal in an extremely precise way.

If the range extension is manipulated, the transmission time of the radio signal between the transmitter and the receiver is too long and the car is stuck. For safety reasons, more and more carmakers are relying on this technique, such as Audi, BMW, Ford, Genesis, Mercedes, Skoda and Volkswagen.

In addition to UWB technology for the radio dongle, BMW offers the digital dongle Plus as an option for a variety of models, particularly the BMW 220i Active Tourer. This allows the owner to deposit the electronic key in the digital wallet of their mobile phone. For this to work, you must first download the “My BMW” app to your own phone.

For those who opt for the radio key, the door magically opens just before you get there and also locks automatically shortly after you get out of the car. It is also possible to start the engine by pressing the start button on the center console, because as soon as the owner of the key enters the car, he is recognized by it.

We tested the UWB car key with this BMW 220i and an iPhone / © Alexander Hauk

The app offers many other information and features. For example, it is possible to read the current fuel level and approximate range. The application also allows you to lock and unlock the vehicle by pressing the corresponding symbol. If you have forgotten where the car is, just press the “Find a vehicle” button and the exact position will be shown on a map.

Even if your smartphone battery fails, everything is planned. All the driver has to do is grab the phone directly against the door handle. The NFC chip built into the phone unlocks the doors. In addition, every BMW customer continues to receive a traditional radio key with keys, in case of loss or theft of the mobile phone. The digital key can also be shared with other people, such as family members, through the app.

Digital key

With an iPhone or a classic key? For a growing number of brands and vehicles, the user has a choice. / © Alexander Hauk

This is how UWB technology works

Several chips are integrated into the vehicle and receive encrypted radio signals from the smartphone. The time measured for the transmission and reception of these signals determines the exact spatial position of the rightful owner of the car. Only when the driver is sitting in the car can it be started.

In addition to BMW, many other car manufacturers rely on UWB. At Audi, the technology is currently available for the classic radio keys of the A3 and Q4 e-tron models. All future models based on the new PPE (Premium Platform Electric) and PPC (Premium Platform Combustion) vehicle platforms will be available with the new technology. “The first models of the new platforms will be unveiled next year,” said Michael Crusius, spokesman for Audi.

uwb car key

The BMW app also offers other benefits. For example, it is possible to take a look inside the car. / © Screenshot: Alexander Hauk, Edition: NextPit, Photo: DenPhotos /

At Skoda, UWB technology is currently present in the Octavia and Enyaq remote controls. “Other series are expected to be equipped with this technology,” said Karel Müller, a spokeswoman for Skoda. According to Michael Schweitzer of Volvo Cars, the Swedish carmaker does not currently offer any vehicles with UWB technology. A Volvo spokesman, however, said that this will be taken into account when planning future models.

It’s only possible with modern smartphones

The technical condition of this exceptional key experience is, in addition to a suitable car, a compatible smartphone. For example, Apple has equipped all iPhone models of the iPhone 11 with a UWB chip. The Samsung Galaxy Note 20 Ultra, Samsung Galaxy S21 + and Ultra, Galaxy S22 series as well as Z Fold 2 and Z Fold 3 also support wireless technology. In the Xiaomi range, only Mi-Mix models are currently supported, while Google has the Pixel 6 and Pixel 6 Pro.

However, UWB technology is not limited to smartphones. It also integrates a chip for the Apple Watch 6 and Apple Watch 7, as well as the Apple AirTag, the Apple HomePod mini and the Samsung Galaxy SmartTag.


The iPhone 13 series supports the UWB / © NextPit standard.

Because UWB enables accurate positioning and technology enables large packets of data to be transmitted across an extremely wide spectrum, the technology is also attractive to many application areas, both indoors and in buildings and outdoors. Parallel use of WLAN or Bluetooth is no problem, as the frequency ranges do not overlap and therefore there can be no interference.

A great future for the UWB

With the IoT (Internet of Things), UWB has the potential to change the world and make everyday life a little safer and more comfortable. Not only cars, but also apartment doors, front doors or garage doors could be equipped with it. The aforementioned Apple and Samsung trackers can help you find out-of-place items, such as lots of keys.

UWB also allows inland navigation. Because this technology can locate objects up to an inch, it will also be possible in the future to control smart home devices. Simply point your smartphone at a compatible device. The device is then recognized and used by an on-screen application. However, the use of WLAN and Bluetooth is even more advantageous, so this convenience will probably not be available for some time.

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