UWB digital car keys, how does it work?

The so-called Keyless or keyless systems for the car are practical, but not unanimous. Current security solutions that make a conventional car key redundant can be thwarted. Many high-end car owners who are victims of theft can attest to this. With the so-called Ultrawideband (UWB) technology, more and more car manufacturers want to put an end to criminal acts. 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 domestic market.

Keyless systems ensure that the car is unlocked automatically as soon as its owner approaches – without having to take the key in hand or press a button on the key. It is also possible to start the engine by pressing a button, without having to switch on the ignition. With current systems, however, comfort is at the expense of safety, as it is possible to outsmart them with a little technical knowledge or a reasonable financial investment.

If the user approaches the car with his iPhone in his pocket, the door is unlocked automatically. If you pay attention, you can hear the unlock just before pulling the door handle. / © Alexander Hauk

With the traditional Keyless technique, the system actually measures the reception level of the key’s radio signal, without checking whether the measured reception level makes sense. Sometimes it is only necessary for the signal level to be high enough for the car doors to be unlocked.

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

Several car manufacturers are dependent on UWB

A so-called relay attack as previously described 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 accurate way.

If the range extension is manipulated, the transmission time of the radio signal between transmitter and receiver is too long – and the car remains blocked. For safety reasons, more and more car manufacturers are relying on this technology, including 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 several models, especially for the BMW 220i Active Tourer. This allows the owner to deposit the electronic key in the digital wallet on their mobile phone. For this to work, you must first download the “My BMW” application on your own phone.

For those who choose the radio key, the door is magically unlocked just before it is reached and is also locked automatically shortly after leaving the car. It is also possible to start the engine by pressing the start button on the center console, because as soon as the key owner 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 the approximate range. The application also allows the vehicle to be locked and unlocked by pressing the corresponding symbol. If you have forgotten where the car is, simply press the “Find a vehicle” button and the exact position will be displayed on a map.

Even if the smartphone battery fails, everything is planned. All the driver has to do is hold his 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 if the mobile phone is lost or stolen. The digital key can also be shared with others, such as family members, through the app.

Digital key

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

How UWB technology works

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

In addition to BMW, several other car manufacturers are dependent on UWB. At Audi, the technology is currently available for the classic radio keys on 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 on 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, editing: NextPit, photo: DenPhotos / Shutterstock.com

At Skoda, UWB technology is currently present in the remote controls for the Octavia and Enyaq models. “The plan is for other series to be equipped with this technology,” explains Karel Müller, spokesman for Skoda. According to Volvo Cars’ Michael Schweitzer, the Swedish carmaker currently does not offer vehicles with UWB technology. However, a spokesman for Volvo said that this will be taken into account when planning future models.

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 from iPhone 11 with a UWB chip. 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 series, only the Mi-Mix models are currently compatible, while at Google it is the Pixel 6 and Pixel 6 Pro.

However, UWB technology is not limited to smartphones. A similar chip is also integrated in the Apple Watch 6 and Apple Watch 7 as well as the Apple AirTag, Apple HomePod mini and Samsung Galaxy SmartTag.


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

As UWB enables accurate positioning and technology enables the transmission of large data packets over an extremely wide frequency spectrum, the technology is also attractive for many applications – both indoors and in buildings and outdoors. Parallel use of WLAN or Bluetooth is not a problem because the frequency ranges do not overlap – and therefore there can be no interference.

A great future for UWB

With 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 already mentioned trackers from Apple and Samsung can help find misplaced items, such as a bundle of keys.

UWB also allows indoor navigation. Since this technology can locate objects down to centimeters, 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 can be operated via an app on the screen. However, the use of WLAN and Bluetooth is even more advantageous, which is why this comfort will probably not be available for some time.

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