Bluetooth Channel Sounding: Key Solutions

September 26, 2024
Jason Marcel
Access Control, Bluetooth Low Energy, Broadcast, Channel Sounding, Connected Device, Digital Key, Item Finding, Location Services

Connection is one thing we all share. It keeps our world in motion and our lives meaningful. For more than 25 years, Bluetooth^® technology has created connections that have opened new markets, shaped culture, and enriched lives. What began as a simple, wire replacement technology has become the invisible thread that enables countless connected devices that make our lives safer, more productive, and more joyful, connecting us to each other and our world like never before. From remote controls to gaming controls, fitness trackers to item trackers, and smart locks to car locks, Bluetooth connected devices have become an ingredient of everyday life, with 5.4 billion forecasted to ship in 2024 alone.

CS Item Finding 4 Hero

Though Bluetooth technology has been primarily known for its ability to provide wireless communication between two devices, the Bluetooth Special Interest Group (SIG) member community has also pioneered advancements to the technology that grant devices the ability to understand their position in relation to each other. For over a decade, developers have leveraged Bluetooth RSSI (received signal strength indicator) as a coarse-ranging feature capable of estimating the distance between two devices, helping Bluetooth devices better anticipate user needs and become more intelligent, responsive, and intuitive. Bluetooth RSSI has ushered in a wide range of novel use cases, including Find My networks and digital key solutions, offering a glimpse into what can be achieved when a device can understand its location in relation to another. That potential inspired a group of key Bluetooth SIG members to come together to enhance the accuracy and security of Bluetooth device ranging capabilities.

“Infineon is excited to bring accurate, secure, fine ranging with Bluetooth Channel Sounding to car access and smart home markets.”

– Shantanu Bhalerao, Infineon

This effort led to the introduction of Bluetooth^® Channel Sounding, an entirely new protocol stack, including a new PHY (physical layer) designed specifically to enable secure, fine ranging between two Bluetooth devices. This innovation brings true distance awareness, introducing transformative benefits across various applications. The user experience of Find My solutions can be greatly improved, making it easier and faster to locate lost items. In digital key solutions, Bluetooth^® Channel Sounding will add a robust layer of security, ensuring that only authorized users within a specified range can unlock doors or access secure areas. By infusing billions of everyday devices with true distance awareness, Bluetooth^® Channel Sounding unlocks a world of possibilities for developers, freeing them to imagine and create innovative experiences that will continue to enhance our connection with our devices, one another, and the world around us.

Bluetooth^® Channel Sounding can bring true distance awareness to a wide array of Bluetooth connected devices, unlocking a world of possibilities for developers and enabling them to imagine and create innovative experiences that enhance our connection with our devices, one another, and the world around us. When connected devices are distance-aware, a range of new possibilities emerge.

“Bluetooth® Channel Sounding is a big step forward for Bluetooth technology,” said Shantanu Bhalerao, Infineon’s VP of the Bluetooth product line. “As a leader in automotive and IoT, Infineon is excited to bring accurate, secure, fine ranging with Bluetooth Channel Sounding to car access and smart home markets. “

Bluetooth^® Channel Sounding: A Technical Overview

This paper provides an overview of the forthcoming update to the Bluetooth^® Core Specification. The update adds Bluetooth Channel Sounding, a new feature that enables secure fine ranging between two Bluetooth devices.

LEARN MORE

Bluetooth Find My Solutions

Attaching Bluetooth tags to personal items such as keys, wallets, backpacks, or luggage was just the beginning of the Find My phenomenon. Now, a rapidly increasing number of Bluetooth devices embed Find My capabilities, introducing the possibility of any Bluetooth connected device becoming a Find My device. When a Bluetooth Find My device is misplaced, its owner simply launches an application on their smartphone or tablet to locate it, bringing added convenience and peace of mind.

“Bluetooth® Channel Sounding is poised to bring true distance awareness to a vast array of Bluetooth devices, unlocking new possibilities for distance-aware applications across various industries.”

– Joonsuk Kim, Samsung Electronics

Existing Bluetooth Find My solutions have leveraged Bluetooth RSSI to determine the general vicinity of an item. Using Bluetooth^® Channel Sounding, developers can now add true distance awareness to a Find My device, improving the user experience and making it significantly easier and quicker for users to locate lost items.

“Bluetooth® Channel Sounding is poised to bring true distance awareness to a vast array of Bluetooth devices, unlocking new possibilities for distance-aware applications across various industries,” said Joonsuk Kim, executive vice president of the System LSI Connectivity Team at Samsung Electronics. “With Bluetooth® Channel Sounding, we’re able to elevate the performance of ‘Find My’ applications by delivering centimeter-level accuracy, helping our customers find important items with greater ease. Additionally, Bluetooth® Channel Sounding enhances the security of digital key solutions, providing an extra layer of protection for keyless entry users. These are just a few examples of the transformative potential of Bluetooth® Channel Sounding, with many more possibilities waiting to be realized.”

Bluetooth Digital Key Solutions

2408 Event IMG Update Channel Sounding 3

Bluetooth^® technology has once again expanded the role of the smartphone in everyday life by enabling it to be used as a convenient and secure digital key. Everything from cars and doors to gates, safes, and bikes are turning to Bluetooth® technology to enable keyless access and provide a more secure locking mechanism.

Current Bluetooth digital key solutions rely on Bluetooth® RSSI to estimate the distance between lock and key. Using Bluetooth^® Channel Sounding, developers can enhance the security and user experience of digital key solutions, ensuring a lock only opens when the authorized device is within a certain distance. This significantly reduces the risk of unauthorized access from man-in-the-middle (MITM) relay attacks.

“The ICCE is committed to developing industry standards and fostering cross-industry collaboration to enable seamless intelligent in-car services,” said Ren Feng, chief secretary of the Intelligent Car Connectivity Industry Ecosystem Alliance (ICCE). “We are therefore studying the addition of Bluetooth® Channel Sounding technology as one of the ranging methods in the ICCE car key standard and we look forward to integrating it.”

The Future of Bluetooth Channel Sounding

“Bluetooth® Channel Sounding revolutionizes proximity and location capabilities, propelling Bluetooth technology into a new era.”

– Ross Sabolcik, Silicon Labs

Beyond Find My and digital key solutions, Bluetooth Channel Sounding has the potential to bring benefits to many connected device solutions, transforming the way we interact with our connected world. For instance, Bluetooth human interface devices (HID), such as mice, keyboards, and game controllers, could automatically switch between active and inactive states based on their distance from a smartphone, tablet, or laptop. For Bluetooth human-machine interface (HMI) solutions, adding Bluetooth^® Channel Sounding can enhance personnel safety by only allowing their usage from a safe distance. Likewise, Bluetooth device networks, such as those used for wireless lighting control, can self-optimize their configuration to enhance system performance. The opportunities are endless.

“In a world where location awareness is critical, Bluetooth® Channel Sounding revolutionizes proximity and location capabilities, propelling Bluetooth technology into a new era,” said Ross Sabolcik, Silicon Labs SVP of the Industrial and Commercial Business Unit. “With a legacy of empowering developers with the full potential of Bluetooth technology, Silicon Labs looks forward to helping create an accelerated path to groundbreaking Bluetooth products equipped with Bluetooth® Channel Sounding.”

To learn more about the intricacies of this new Bluetooth feature, check out the Bluetooth^® Channel Sounding Technical Overview.

Bluetooth® Channel Sounding: A Technical Overview

This paper provides an overview of the forthcoming update to the Bluetooth® Core Specification. The update adds Bluetooth Channel Sounding, a new feature that enables secure fine ranging between two Bluetooth devices.

LEARN MORE