Bluetooth Channel Sounding for Distance Measurement and Other Applications

At the Works With event organized by Silicon Labs in Bangalore on October 30, 2025, Vijaya Krishna presented demonstrations and details on the use of Bluetooth channel sounding for distance measurement, along with related technologies including PAWR, Bluetooth mesh, ambient IoT, LE Audio, and upcoming features.

Channel Sounding Demo: Dynamic Distance Tracking

Channel sounding enables distance measurement using a Bluetooth chip without additional bill of materials cost. In the setup, one stationary board serves as the initiator, and a second board moving with a person acts as the reflector. Both use EFR32 MG24 devices.

Four scenarios were demonstrated:

1.  Line-of-sight walking : The reflector is held in hand while walking away from the initiator toward a metallic elevator. Multipath reflections occur, but distance measurements remain stable.

2.  Non-line-of-sight in pocket : The reflector is placed in the person’s pocket. Interference increases from multipath reflections and human body absorption of RF signals. Measurements show minimal fluctuations.

3.  High speed with line-of-sight : The person runs away from and back toward the initiator while holding the reflector. Measurements...