Each new revision of Bluetooth brings a key major upgrade. For Bluetooth Core version 6.0 of the popular short-range wireless standard device that major upgrade is Bluetooth Channel Sounding.
Channel Sounding enables secure distance measurement between two Bluetooth devices and promises many new innovative proximity and distance ranging applications. And because the technology is expected to be widely adopted in smartphones and a broad range of other battery-powered Bluetooth LE products, it is designed to bring standardization and interoperability to distance ranging.
Channel Sounding builds on previous location and proximity awareness technologies included with Bluetooth. For example, the Find Me Profile was included when Bluetooth LE was first released (as a “hallmark element” of Bluetooth 4.0).
Then, Received Signal Strength Indicator (RSSI) was used to provide an approximate estimate (such as “close by”, “connected” or “out of range”) of the distance between two Bluetooth devices. While the accuracy of RSSI is not high, it still proved a useful technology for some applications such as locating a smartphone using a smartwatch with a limited accuracy that often could reach only up to a few meters.
Later, Bluetooth Direction Finding was introduced. The technology determines the distance between devices using sophisticated hardware, angle measurement, and triangulation. With the appropriate supporting technology, accuracy is significantly improved compared with RSSI. However, it has been adopted only for specific use cases due to the required relatively bulky antenna arrays that increase the complexity of the design.
Channel Sounding now brings a simpler and more reliable solution for Bluetooth LE distance ranging applications. It can be supported by very simple devices or as an addition to a more advanced product without extra hardware costs and with a minimal software footprint. And power consumption is as low as regular data transfer over Bluetooth LE. Finally, Channel Sounding supports various hardware and software configuration options for accuracy, latency, security, and power consumption.
Channel Sounding uses two distinct ranging methods called Phase-Based Ranging (PBR) and Round-Trip Timing (RTT) to determine the distance between two Bluetooth devices. These two methods combined with profile-level features bring accuracy, reliability, security, and convenience to new and existing applications without adding significant complexity to hardware design or notably increasing cost.
Channel Sounding will enhance existing applications as well as power new ones. One example is improved tags. Today’s tag solutions work well but problems can arise when the achievable accuracy of the existing technologies is not enough to locate the device, and the workaround solutions such as the vibration or sound they emit when activated is muffled by sofa cushions or blankets. Channel Sounding will enable more accurate distance measurement allowing for ‘hot-cold’ proximity indication that overcome the limitations of sound or vibration alarms.
Another application that will gain an advantage from Channel Sounding is the smart lock. Presence detection of the person wishing to activate the lock will be improved and smart locks will benefit from robust, built-in security features, including protection against man-in-the-middle and relay attacks. Appliances will also be enhanced by the technology. For example, physical context information provided by Channel Sounding will assist with safety features that activate control functions only when the user is near the device.
Nordic recently released its new series of wireless SoCs, the nRF54L Series. The SoCs are ready to be qualified against Bluetooth Core v6.0 with support for Channel Sounding. Development support for the nRF54L Series comes through an update to Nordic’s unified and scalable software development kit, the nRF Connect SDK. The flagship nRF54H Series also supports the technology.
According to Fortune Business Insights, the asset tracking market alone is projected to grow to $59.64 billion by 2032. With the advent of Bluetooth Channel Sounding, developers now have a powerful new tool to help them build winning applications for this market sector and many others.