Bluetooth Mesh Positioning Using CTE for Indoor Navigation

The patent introduces CTE (Constant Tone Extension) information as an intermediary mechanism between Bluetooth nodes and terminal devices. CTE enables precise measurement of signal propagation time and path length, allowing the system to calculate accurate distances and positions despite environmental reflections and interference. This intermediary measurement approach resolves the contradiction by providing reliable positioning data without relying solely on signal strength packets that are susceptible to environmental variations.

The patent replaces the traditional signal strength-based positioning mechanism with a time-of-flight and path-length measurement mechanism. By using CTE information to measure the time it takes for signals to traverse known paths between Bluetooth nodes and terminal devices, the system substitutes the unreliable signal strength metric with a more accurate temporal measurement approach, thereby improving positioning precision while maintaining Bluetooth technology.

The patent segments the positioning system into multiple Bluetooth nodes distributed throughout the environment, each capable of independently measuring distances to terminal devices using CTE information. Instead of relying on a single centralized node with limited transmission range, the system divides the coverage area into multiple zones served by different nodes. This segmentation allows the terminal device to receive positioning information from multiple nodes, effectively extending the overall positioning range beyond the limitations of individual Bluetooth transmissions.

The patent transitions from traditional two-dimensional or point-to-point Bluetooth positioning to a three-dimensional multi-node spatial positioning system. By establishing multiple Bluetooth nodes at different spatial locations and using CTE to measure path lengths in three-dimensional space, the system creates a volumetric positioning capability. This dimensional expansion allows the terminal device to be positioned accurately even when individual node-to-device transmissions are limited in range, as the system can triangulate position based on measurements from multiple nodes in three-dimensional space.