NXP explains how Bluetooth® Channel Sounding will enhance automotive digital keys
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Bluetooth® Channel Sounding is attracting significant attention from various industries as a technology that can achieve high-precision ranging at low implementation costs while leveraging Bluetooth technology’s widespread ecosystem. Expectations are high in the automotive sector, not only for the high-precision ranging capabilities but also for security enhancements, with industry organizations already advancing their application to digital key standards.
Kuniyuki Tomizu of NXP Japan’s microcontroller division, who is involved in Bluetooth LE marketing, highlights the potential of Bluetooth Channel Sounding and how it will enhance automotive digital key applications across various use cases.
Digital key evolution
Bluetooth Channel Sounding can be utilized broadly across all applications that require distance measurement. Representative use cases include solutions for tracking the location of lost items, and access control applications such as car keys, which is the focus of this discussion.
With Bluetooth® LE at the center, more convenient and user-friendly solutions are being offered every day, with the use of cars as power sources and batteries becoming commonplace. In this context, controlling car features via Bluetooth connectivity is expected to become standard practice. Various industry organizations are already advancing standardization using Bluetooth Channel Sounding, with the Car Connectivity Consortium (CCC) developing a standard for automotive digital key applications.
High anti-theft performance
Bluetooth technology is ideal for car theft prevention, and Bluetooth Channel Sounding achieves robust multi-layered security by combining round-trip time (RTT) and phase-based ranging (PBR).
A commonly used method in car theft is relay attacks, a type of man-in-the-middle attack. Smart keys are designed so that a key inside a house will not open a car in a separate garage due to distance. However, using compact relay devices, bad actors can sometimes use sophisticated techniques to amplify these signals to make them appear as if the key is located where the relay device is positioned.
Ranging technology can be applied to prevent such relay attacks by measuring true distances between smart keys and cars. Bluetooth LE anti-relay keys that introduce countermeasures against relay attacks already exist, and we anticipate the development of keys combining Bluetooth Channel Sounding in the near future. In addition to incorporating Bluetooth Channel Sounding functionality, smartphones are serving as key replacements to greatly enhance user convenience.
Know-how for performance improvement
Bluetooth® Channel Sounding has taken the first step toward commercialization for the market. Currently, the technology is expected to be more user friendly and precise.
As one of the contributors to Bluetooth Channel Sounding development, NXP helped identify several emerging areas that will achieve the full precision of Bluetooth Channel Sounding. Naturally, it is crucial to use hardware and software built on accumulated experience and expertise. Second, sufficient tuning needs to be implemented in the design of antennas used for radio wave transmission and reception. The third factor is the algorithms that process the data obtained from ranging measurements, which significantly influence the realization of accurate ranging with minimal error. Testing and verification work, as well as analyzing evaluation results and applying them to software and hardware improvements, is also necessary for improving accuracy.
Diverse solutions that utilize Bluetooth® Channel Sounding to achieve both high accuracy and high reliability will play an important role in widespread adoption across the industry.
Power consumption can also be expected to decrease through the adoption of products that incorporate dedicated hardware for efficient computation, in addition to reducing ranging time. Power consumption is becoming an increasingly important issue as vehicles incorporate progressively more electric elements, and Bluetooth Channel Sounding can contribute to reducing that power consumption. As various technologies and functions continue to emerge, diverse solutions that utilize Bluetooth Channel Sounding to achieve both high accuracy and high reliability will play an important role in widespread adoption across the industry.
Bluetooth channel sounding begins with security for digital keys in automobiles, including two-wheelers, and as ranging performance improves, the potential of this technology will continue to expand. Continued collaboration across industries will be key to refining these solutions and ensuring they meet the demands of tomorrow’s connected mobility landscape.
