Bluetooth technology, as a radio technology supporting short-range wireless communication, enables low-cost, low-power, and efficient data and voice communication between devices. It plays a crucial role in four major areas: audio transmission, data transmission, location services, and device networking.

At the 2024 International AIoT Ecosystem Development Conference, Lu Gongyu from Bluetooth SIG introduced channel sounding technology, which overcomes existing SSI limitations by providing ±0.5 meters accuracy and improved security. This advancement, part of Bluetooth's evolution since 2016, includes improvements like high-speed, long-range, Mesh networking, direction finding, LE audio, PAWR, and channel echo, addressing challenges in traditional beacon and RSSI-based location services.

Channel probing technology combines PBR and ToF measurement methods, with the integration of RTP technology into BLE data transmission, significantly improving positioning accuracy to ±0.5 meters. This technology also enhances security by using encrypted, timestamped data packets to effectively prevent man-in-the-middle attacks, and ensures consistency by comparing ToF and RTP measurement results, providing robust security.

Specifically, the initiating device sends a signal to the reflector device, which then returns the signal. Upon receiving the returned signal, either party can calculate the distance based on the phase difference between the transmitted and received signals. This process is repeated at different frequencies to improve measurement accuracy.

Lu Gongyu's channel probing technology uses a new protocol stack for connection-oriented range measurement between devices, ensuring they are within the preset distance before connecting. It combines PBR and RTT methods for accurate distance measurement. To prevent spoofing, it employs a DRBG to shuffle bit sequences and randomize packet details. The technology supports multiple channels and frequency hopping within the 2.4GHz band, improving signal quality and coverage, and enhances defense with NADM. It enhances Bluetooth distance sensing and optimizes features like “Find My,” digital keys, and other device network functionalities.