Bringing Bluetooth® Channel Sounding to Automotive and Beyond with KW47

NXP’s new Channel Sounding-certified KW47 and MCX W72 wireless MCUs are set to help automakers with distance measurement, bringing an additional ranging solution for car access and autonomous systems, and will be utilized across a broader spectrum of applications.

Originally conceived as a simple communications interface, Bluetooth® technology is on track to find new life as a distance-sensing technology. This is thanks to Bluetooth® Channel Sounding, included in Bluetooth® Core 6.0, which was released in August 2024. In a significant evolution since the 2016 release of the new LE 2M and Coded PHYs, this breakthrough opens the way to a new class of autonomous, location-aware systems for augmented awareness of the environment.

NXP’s First Automotive Bluetooth 6.0 Channel Sounding-Qualified MCU with CAN and AUTOSAR Support

Bluetooth Channel Sounding, with its power efficiency, enhanced security and higher accuracy relative to legacy systems using received signal strength indicator (RSSI ), will bring distance awareness to the world of technology. When connected devices are distance-aware, a range of new possibilities emerge, and NXP is advancing innovation with the new KW47 family of single-chip wireless devices. This is NXP’s first automotive-qualified device to support
Bluetooth Channel Sounding
included in Bluetooth Core 6.0, offering excellent Bluetooth LE localization. KW47 is aligned with the latest automotive industry requirements such as AEC-Q100 Grade 2 qualification, compliance with ASPICE and MISRA software quality standards and support for AUTOSAR leveraging controller area network (CAN) communication.

How Is It Different? Using Bluetooth As a Distance Sensor Across Market Segments

Traditional Bluetooth systems use RSSI  for localization, a method with limited accuracy and known security vulnerabilities. In contrast, Bluetooth Channel Sounding uses phase-based ranging (PBR) for accuracy combined with round trip time (RTT) for end-to-end security. This allows devices that support Bluetooth Channel Sounding to consistently determine distance with enhanced accuracy and security. The KW47 brings Bluetooth Channel Sounding capabilities to the automotive world, enabling
Bluetooth LE
devices to accurately determine the driver’s distance. Driver movement and behavior can be predicted, since the driver can be detected up to 100 meters away and their approach closely measured, achieving a typical distance accuracy of 20-50 cm at close range. So, the intended operation can be triggered not too early and not too late but at just the right time, with smarter, more secure features like pre-authorization for entry and seamless unlocking.

The result is a more refined and automated user experience. The system knows when the driver is approaching, when to activate different functions, and when to stay dormant—improving battery life while ensuring responsiveness and security. Meanwhile, the
MCX W72
extends these capabilities beyond the automotive market. As part of a scalable product family that includes the KW47, the MCX W72 offers the same Bluetooth Channel Sounding features for industrial IoT, smart infrastructure and consumer applications.

Inside KW47 and MCX W72, Extra Security and a Dedicated Localization Engine

Both KW47 and MCX W72 combine high-performance wireless connectivity with built-in intelligence and security. The platform incorporates a dedicated localization compute engine (LCE), which accelerates complex positioning algorithms up to 10 times faster than the main Cortex M33 core. This means faster response times and improved power efficiency in real-time ranging applications, ideal for secure access and indoor navigation applications. Security is handled by the integrated
EdgeLock® Secure Enclave Core Profile, which isolates sensitive operations such as cryptographic key storage and trusted boot processes. The advanced Bluetooth LE radio is software-defined, using 24 simultaneous connections as reference for internal SDK validation, offering robust long-range communication with up to +10 dBm transmit power.

The Complexities of Qualification

Qualifying a product for Bluetooth Core 6.0, especially with support for advanced features like Bluetooth Channel Sounding, is a complex, involved and evolving process. This requires flexibility and close collaboration with the Bluetooth Special Interest Group (SIG ), attendance at interoperability events and alignment with emerging standards. NXP’s early involvement in shaping the specification, combined with deep system expertise and consistent participation in global interoperability testing events, highlights our role as a standard-setter and technology implementer. After intense work on many fronts, we are delighted to welcome KW47 as NXP’s first automotive-grade chip that supports Bluetooth Channel Sounding.

Part of a Larger Family: KW47 and W72x

Bluetooth technology is now pervasive across industries, and NXP’s portfolio reflects this ubiquity. The KW47 integrates Bluetooth Channel Sounding, enabling precise distance measurement and localization for automotive applications, while the MCX W72 brings these advanced capabilities to industrial IoT systems, supporting accurate positioning and spatial awareness in complex environments.

The MCX W72 extends the same platform architecture into autonomous homes and buildings where precise locationing, secure access and seamless connectivity are key. Multi-protocol radio supporting Zigbee and Thread combined with relevant memory footprint enables Matter, making it an impressive combination of skills.

As part of a shared platform approach, localization strategies are being harmonized to encourage interoperability. This is why NXP made prototypes of KW47 and MCX W72 silicon platform and algorithms available early to EcoSystem partners. NXP customers, phone OEMs, tool vendors and test equipment makers are already working with NXP development boards to discover the full potential of Bluetooth Channel Sounding ensuring full readiness after extensive interoperability testing (IOP) at BT SIG before Core Specification release.

Working with the Automotive Car Access Ecosystem

In CCC-compliant architectures, Bluetooth LE and Ultra-Wideband (UWB) work together to authenticate user presence and enable secure vehicle entry. It is considered in Car Access Consortiums for digital key systems to incorporate Bluetooth Channel Sounding and other Bluetooth Core 6.0 capabilities. The KW47 chip will bring enhancements and power efficiency to the mix, using Bluetooth Channel Sounding to manage when and how UWB is activated. This is expected to improve system-level performance, delivering the same high-end user experience. NXP has always been a principal contributor to the CCC Standard and EcoSystem. The KW47 continues that legacy as the third generation of Bluetooth LE, with a qualified, future-ready solution for digital key solutions. While Car Connectivity Consortium (CCC) has worldwide recognition, the KW47 is also supporting Intelligent Connected Car Ecosystem Alliance (ICCE) and Intelligent Car Connectivity Open Alliance (ICCOA) as alternative solutions in China.

Sampling Now, Production Ready by End 2025

With qualification now achieved through the Bluetooth SIG, the KW47 stands as NXP’s first automotive-grade wireless MCU to support Bluetooth Channel Sounding and decision-based advertising filtering (DBAF) with Bluetooth Core 6.0 adding other features like Bluetooth LE PAwR for tire pressure monitoring system (TPMS) from Bluetooth Core 5.4. KW47 and MCX W72 are sampling today, with production readiness targeted for December 2025. Development tools and reference designs are available to help customers quickly evaluate and integrate the device into their platforms, building onto experience of
KW45/MCX W71.

For automotive Bluetooth applications, visit
KW47 and for industrial applications and beyond visit MCX W72.