The momentum on digital keys for cars is picking up as NXP announced its latest ultra-wide band (UWB) chip to enable smartphones to unlock cars, while BMW is driving the next-generation Digital Key 3.0 specification featuring UWB through the Car Connectivity Consortium (CCC).

Following on from its September launch of its UWB chipset for mobile devices, NXP has now introduced the counterpart UWB chip for the car, the NXP NCJ29D5. This means it now has a UWB solution for the key fob, smartphone and car, which the company said opens up the possibility for true handsfree smartphone access and remote parking, enabled by the precise distance management and localization capability of UWB technology.

Ultra-wideband technology is considered to provide precise, secure, real-time localization capabilities unrivaled by other wireless technologies such as Wi-Fi, Bluetooth, and GPS. Devices equipped with a UWB radio that come into range of another UWB-based device start ranging using time of flight (ToF) measurements between the devices, calculating the roundtrip time of challenge/response packets. The technology uses a large 500 MHz channel bandwidth with short pulses of about 2 ns each, which helps achieve centimeter accuracy, with the positioning process enabling accurate tracking in real time.

As explained by the FiRa consortium which launched earlier this year to revive UWB technology for fine ranging applications, a UWB-enabled system can know, with a very high degree of certainty, the precise location of a device and whether it’s stationary or moving toward or away from a given object. For example, a UWB-enabled system can sense if you’re moving toward a locked door and it can know if you’re on the inside or outside of the doorway, to determine if the lock should remain closed or open when you reach a certain point.

This precision allows applications to define the exact intent range to avoid false triggering, and also help prevent relay station attacks, which have now become common on many advanced cars with keyless entry fobs. With UWB, an attempt to intercept and amplify a signal during a relay attack will only delay the arrival of the responding device’s acknowledgement signal, which should then make it obvious to the UWB-based lock that the responding device is actually farther away, not closer. According to the FiRa consortium, any UWB signal that attackers succeed in intercepting and boosting won’t trick a UWB-equipped lock into opening. In addition, the extension of IEEE 802.15.4z standard adds PHY level protection to all known attacks on legacy UWB radio.

NXP said that with its latest UWB chip for the car, this precision enables spatial awareness within UWB-equipped cars, mobiles, and other smart devices, enabling the car to know exactly where a user is. Speaking to EE Times, Markus Staeblein, vice president and general manager of secure car access at NXP, said this means smartphone-based car access now offers the same level of convenience as state-of-the-art key fobs. Users can open and start cars, while leaving their phones in their pockets or bags, and enjoy secure remote parking via smartphone, and there is also an additional level of protection against car theft through relay attacks.

UWB chip block diagram

The new NCJ29D5 UWB chip from NXP (Source: NXP)

He explained the background to the latest UWB chip and its potential for other automotive applications. “The previous chip we launched in September, the SR100T, enabled UWB in the mobile phone. With the new NCJ29D5 chip, this now enables UWB on the car side. With UWB, the car can detect how the owner with the smartphone is approaching the car, and within certain distances as defined in specifications from the Car Connectivity Consortium, can authenticate and enable certain features. For example, when around eight meters away it can enable welcome lights, and when less than two meters away can open the car.” He added this provides true hands-free car access, turning the smartphone into a digital key.

We asked about whether it was really secure to use the mobile phone to unlock the car in this way. He responded that we already use mobile phones for banking, so it’s already used for highly secure transactions. Staeblein continued to explain that the CCC defines the digital key specifications, with the key stored in a secure element within the phone. “Nobody has this key. The car then also has the digital key stored either in a secure element of secure microcontroller. The combined digital key management and UWB technology gives the real time ToF measurement and access allowance.” He said the CCC is working towards ensuring interoperability standards between smartphones and cars.

Staeblein said there are many new potential applications in automotive beyond smartphone access. This includes smartphone valet parking, where cars can be sent to park autonomously via a smartphone application; electric vehicle charging, for autonomous positioning of the vehicle on the charger; drive through payment, using localization for secure on the go payment; and using the car as a key, where it can seamlessly access a garage door and parking.

Remote controlled parking

Potential new automotive applications enabled by UWB include remote controlled or smartphone valet parking (Source: NXP)

“The opportunities that exist in the web of mobility and automotive are vast. As a leading semiconductor manufacturer in these segments, we have the ambition to tap these and bring more seamless and secure mobility experiences to users,” Staeblein added. “We are pleased to jointly work on the required interoperability and standardization for UWB with BMW Group, Continental and other CCC members.”

CCC working on Digital Key 3.0 incorporating UWB
In conjunction with the launch of the new chip, these CCC members are jointly working on UWB implementations together with the IEEE to ensure the best customer experiences at the intersection of the vehicle, mobile, and consumer devices. These standardization efforts aim to enable a global standard for handsfree smart access and other automotive localization use cases based on UWB. Philippe Fournet-Fayat, director at Continental AG for car access systems, said, “Continental is at the forefront in delivering secure localization platforms that will create leading applications that catch the imagination of the power user generation. To deliver new use cases, such as smartphone access and remote parking requires the ultra-precise real-time localization capabilities of UWB.”

BMW Group’s head of development digital access functions, Olaf Müller, said, “Today, the smartphone plays a central role in the digital lifestyle. We are convinced that the smartphone-based comfort access is just the beginning of a series of innovative vehicle-related UWB use cases.” He added, “Our customers want cross-vendor interoperability. Standardization is the only way to achieve this; proprietary solutions are no longer beneficial.” The BMW Group has therefore been driving the creation of a global standard for digital vehicle access within the CCC. Most well-known smartphone producers and automotive manufacturers have already joined the consortium. Standard specifications across industries will also help include all kinds of smart devices, including phones, watches and other wearables.

The second generation (release 2.0) of an NFC-based digital key ecosystem has been announced for late 2019. A key feature is the use of a security chip that works separately from the smartphone operating system. This means it also works if the smartphone cannot be started anymore, because the battery is too low. In the near future, the digital key specification will be enhanced by the UWB-based release 3.0. This will offer maximum anti-theft protection and enable precise localization between the device and the vehicle. As a result, the mobile phone will no longer need to be held directly up to the door handle to unlock the car but can conveniently be left in the pocket. The BMW Group recognized early on that UWB technology would be beneficial over the long term and suitable for global market penetration. The close cooperation with partners and the fact that UWB is already finding its way into more and more customer devices will pave the way for new and innovative digital key features, according to BMW.

Digital key specs leverage NFC, UWB and BLE
The CCC’s Digital Key Release 2.0 specification leverages NFC short-range wireless communication between devices to ensure high interoperability between vehicles and a wide range of devices. To address security in Release 2.0, a secure connection is established between mobile devices and vehicles using NFC, which continues to operate even when the supported mobile device’s battery is low. Mobile devices ensure security by storing digital keys in dedicated, tamper-resistant security chips isolated from the device’s operating system. Mobile developers can build applications that interact with digital keys and vehicles to provide custom, vehicle-specific functionality.

The Digital Key Release 3.0 specification will enhance Digital Key Release 2.0 by adding passive, location-aware keyless access. Rather than having to pull their mobile devices out to access a car, users will be able to leave their mobile device in their bag or pocket when accessing and/or starting their vehicle. To support these new features, the CCC is developing a specification based on Bluetooth Low Energy (BLE) in combination with UWB to enable passive keyless access and to allow secure and accurate positioning.