Indoor Positioning Using Multi-Node FTM Handshakes
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Solution Overview
Problem
Existing indoor positioning technologies require multiple FTM handshakes to determine the position of multiple nodes, leading to high signaling overheads in the network.
Innovation Solution
A method that allows obtaining the position information of two to-be-positioned nodes during one FTM handshake by using time information and position information of at least three collaborative nodes with known positions, reducing the number of required FTM handshakes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple FTM handshakes are performed to determine positions of multiple nodes, then positioning accuracy is improved, but signaling overheads increase
Solution Approach 1:
The patent combines multiple positioning operations into a single FTM handshake process. Specifically, it enables two to-be-positioned nodes to determine their respective positions simultaneously during one FTM handshake between them, rather than requiring separate handshakes for each node. This merging of operations reduces the total number of FTM handshakes from N (for N nodes) to approximately N/2, thereby reducing signaling overheads while maintaining positioning accuracy through the use of at least three collaborative nodes with known positions for triangulation calculation
Solution Approach 2:
The patent makes the FTM handshake process multi-functional by enabling it to serve dual purposes: determining the position of the first to-be-positioned node and determining the position of the second to-be-positioned node simultaneously. This is achieved by having each node act as both a transmitter and receiver, allowing the same communication exchange to provide positioning data for both nodes, thus improving efficiency without sacrificing measurement precision
2Quantity of substance
If one FTM handshake is used to obtain position information of two nodes, then signaling overheads are reduced, but device complexity increases
Solution Approach 1:
The patent segments the positioning calculation process into distinct functional modules: (1) time information acquisition module that collects timing data from the FTM handshake, (2) collaborative node position module that stores known positions of reference nodes, and (3) position determination module that performs the actual triangulation calculations. This segmentation allows each module to handle specific tasks independently, reducing overall system complexity despite the multi-functional nature of the FTM handshake
Solution Approach 2:
The patent performs preliminary actions by pre-establishing a network of collaborative nodes with known positions before the actual positioning operation. These collaborative nodes are configured in advance and their position information is stored and ready for use. This preliminary setup simplifies the real-time calculation process, as the system only needs to perform distance calculations and triangulation using pre-available reference data, rather than establishing the entire positioning infrastructure during the FTM handshake itself
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach decreases the quantity of FTM handshakes needed, thereby reducing signaling overheads in the network, and improves calculation precision by aligning internal clocks.
Implementation Method 1
U sends an FTM request to the AP. After receiving the FTM request, the AP initiates FTM measurement, and sends an FTM action frame (fine timing measurement action frame). After receiving the FTM action frame, U sends a fine timing measurement response frame
Data Source
AI summary
A positioning method includes: obtaining first time information of a first to-be-positioned node, second time information of a second to-be-positioned node, position information of at least three collaborative nodes with known positions, and third time information of the at least three collaborative nodes with known positions; and determining position information of the first to-be-positioned node and position information of the second to-be-positioned node according to the first time information, the second time information, the third time information, and the position information of the at least three collaborative nodes with known positions.