CSI Position Sensing with ADoA Auto-Calibration
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Solution Overview
Problem
Existing CSI-based Wi-Fi positioning systems require labor-intensive manual calibration for determining AP locations and antenna array directions, and are affected by down-sampling phase differences, hindering large-scale deployment.
Innovation Solution
A CSI-based location sensing method that automatically calibrates by obtaining angle differences of arrival (ADoA) using non-linearly arranged antennas, eliminating the need for manual calibration and phase offset correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual calibration is used to determine AP locations and antenna array directions, then positioning precision can be achieved, but the system requires labor-intensive calibration work and complex deployment procedures
Solution Approach 1:
The system enables automatic calibration where the positioning devices themselves perform the calibration process without external intervention. Multiple positioning devices mutually detect each other's CSI data and automatically calculate relative locations and antenna directions through cooperative measurement, eliminating the need for manual calibration of AP locations and antenna array directions.
Solution Approach 2:
The patent changes the calibration approach from individual device calibration to multi-device cooperative calibration. By having multiple devices mutually detect each other and share CSI data, the system transforms the calibration parameters from absolute (requiring manual input) to relative (automatically calculated), thereby simplifying deployment while maintaining precision.
2Measurement precision
If down-sampling phase difference correction is applied to enable CSI-based AoA calculation, then positioning accuracy is improved, but additional calibration steps and system complexity are introduced
Solution Approach 1:
The system automatically eliminates down-sampling phase differences through mutual detection between multiple positioning devices. Each device detects CSI from others and uses the relative phase relationships to self-correct for down-sampling effects, removing the need for separate phase calibration procedures while maintaining AoA calculation accuracy.
Solution Approach 2:
The patent introduces mutual CSI detection between multiple positioning devices as an intermediary mechanism. By having devices detect each other's signals and share the CSI data, the system creates a reference framework that naturally compensates for down-sampling phase differences without requiring direct intervention in each device's phase correction process.
3Adaptability or versatility
If at least two antennas are installed on each device for AoA calculation, then positioning functionality is enabled, but the requirement for non-linear antenna arrangement increases device design complexity
Solution Approach 1:
The patent specifies non-linear (asymmetric) antenna arrangement instead of linear or symmetric configurations. This asymmetric arrangement of at least two antennas on each positioning device enables the system to calculate both AoA and relative locations more accurately by providing better spatial diversity, while the complexity is managed through automated calculation algorithms.
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
Enables high-precision positioning without manual calibration of AP locations and antenna directions, reducing workload and enabling large-scale deployment.
Implementation Method 1
obtaining CSI data mutually detected between every two devices in N devices... The CSI indicates impact of a communications channel on a feature, for example an amplitude and a phase, of a sent signal
Implementation Method 2
The phase may be used to calculate an angle of arrival (AoA)... obtaining an angle difference of arrival (ADoA) set based on the obtained CSI data, where the ADoA set includes an ADoA of every two devices in the N devices relative to each of the other devices
Data Source
Figure 1~2
Figure 3(a)~3(d)
Figure 4~5
AI summary
Embodiments of this application provide a CSI-based location sensing method. If an antenna array direction of a device is unknown, a location layout of a plurality of devices provided with antennas arranged in a non-linear manner can be constructed based on a geometrical relationship of an angle difference of arrival (ADoA). When the location layout is used for positioning, positioning can reach the same high precision as that of a manual calibration method.