Bluetooth 6.0 – Learn more about Bluetooth channel sounding

The Bluetooth Special Interest Group introduced its latest Bluetooth version 6.0 later this year. This will bring major updates over recent incremental updates, delivering significant enhancements to audio streaming, device networking, and especially location services. Some of the most significant impacts of these new features are enhanced security and greater accuracy in distance measurement.

Overview of the upgrades: 

• Bluetooth channel sounding
• Decision-based advertising filtering and advertiser monitoring
• ISOAL enhancement
• LL extended feature set
• Frame space update 

Bluetooth channel sounding

The new Bluetooth Channel Sounding feature makes it possible to create products capable of calculating the distance between two Bluetooth devices with far greater accuracy than could ever be achieved using the first generation RSSI and path loss method. It works in a completely different way and includes a number of security safeguards that mitigate different types of risk. Bluetooth channel sounding is expected to benefit Find My solutions, digital key products, and many other Bluetooth-connected devices.

Unlike AoA and AoD, which require multiple antennas, increasing the chip's footprint, and can suffer from performance issues in multipath environments, Bluetooth^® channel sounding will introduce a new method for achieving accurate distance estimates known as phase-based ranging (PBR).

In phase-based ranging, an accurate estimate of the distance between the two radios is obtained by analyzing the phase of the radio signal. Essentially, the time of flight of the radio signal, i.e. the distance between the two devices, is accurately measured using phase data.

To measure the phase data, both devices alternately transmit and receive in a coordinated manner. This is repeated several times on different frequencies (channels), which resolves ambiguities and improves accuracy, even in the presence of reflections (multipath), such as in indoor environments.