White Paper How Bluetooth® Channel Sounding Enables Secure Localization and Smart Keys in Automotive Systems
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Why Channel Sounding?
Bluetooth Channel Sounding is a cross-industry technology that can be applied to an endless set of applications that stand to benefit from high-precision ranging at low implementation costs. Since it leverages the existing, extensive Bluetooth ecosystem, all categories of Bluetooth connected devices can benefit from it, including the following:
- Consumer products such as mice, keyboards, and game controllers can manage their power states based on their distance from computers and smartphones
- Industrial applications can monitor whether or not staff is within a safe distance from dangerous working areas
- Smart IOT networks can optimize their behavior, for instance, by managing lighting in public spaces
- Automotive and Home applications can unlock cars and house doors by using dedicated key fobs or smartphones
Why More Security?
Over the past 25 years, Bluetooth® has become almost universally available in billions of products – 5.9 billion devices expected to be shipped just in 2025 – including cars, bikes, doors, gates, and safes that are offering keyless access requiring highly secure locking mechanisms.
The white paper, available for download on this page, examines how Bluetooth Channel Sounding is implemented via deep integration of timing and RF features in the controller and host stack enabling presence detection and distance measurement via methods such as Phase Based Ranging (PBR) and Round-Trip Timing (RTT), as well as direction determination using angle of arrival and angle of departure (AoA/AoD). The combination and availability of such data have helped evolve Bluetooth into a security platform for precise real-time and secure localization enabling developers to create enhanced and more secure applications.
Why Bluetooth LE?
Bluetooth LE offers excellent power management that is essential to the performance of these applications as they are typically integrated in battery powered devices. With this enhanced security in place, cars are expected to be controlled securely via Bluetooth connectivity, so power efficiency is paramount to a great user experience. The Car Connectivity Consortium is already working with several automotive OEMs and Tier1s and mobile OS vendors with the goal to extend the standard for the automotive digital key applications to include Bluetooth Channel Sounding.
More secure anti-theft protection
Bluetooth technology is ideal for car theft prevention, and Bluetooth Channel Sounding achieves robust multi-layered security by combining the Round-Trip Time (RTT) and Phase-Based Ranging (PBR) methodologies. This is particularly important to prevent man-in-the-middle (MiTM) relay attacks as smart keys are designed to be aware of their relative position to the car and will not unlock the car if the measured distance is not within the expected range. Hence, relay devices typically used by bad actors will be detected and discarded. Channel Sounding is going to improve already existing Bluetooth LE anti-relay keys that introduce countermeasures against relay attacks and, with smartphones increasingly serving as key replacements in the future, to enhance user convenience and security.
Bluetooth ‘Find My’ solutions
Find My’ applications are already available in the consumer market with Bluetooth tags that can be used to locate personal items such as keys, wallets, backpacks, or luggage. This is now also being embedded at production time in many devices n with ‘Find My’ capabilities, introducing the possibility of any Bluetooth connected device becoming a ‘Find My’ device. Using Bluetooth Channel Sounding, developers can now add true distance awareness to a ‘Find My’ device as it offers centimeter-level accuracy over considerable distances, improving the user experience and making it significantly easier and quicker for users to locate their lost items.