RSSI Range Accuracy Augmentation with CSI Magnitude
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Solution Overview
Problem
Indoor localization for Wi-Fi devices faces challenges due to complex radio propagation environments, including multipath effects, shadowing, fading, and delay distortion, which affect accuracy and require high complexity and cooperation between devices.
Innovation Solution
The system augments RSSI-based location with CSI magnitude data to determine a magnitude distance (MD) for each subcarrier, allowing for accurate location determination without requiring specific AP orientation information, thus improving accuracy and reducing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If RSSI-based techniques are used for indoor localization, then the system is simpler and easier to implement, but the localization accuracy deteriorates significantly
Solution Approach 1:
The patent combines RSSI measurements with CSI magnitude measurements to create an augmented ranging system. By merging these two measurement types, the system maintains the simplicity of RSSI-based approaches while incorporating the additional accuracy benefits of CSI magnitude data, resolving the contradiction between system simplicity and localization accuracy
Solution Approach 2:
The patent introduces magnitude distance (MD) as a new parameter derived from CSI magnitude measurements. This parameter change allows the system to augment traditional RSSI-based ranging with an additional accuracy dimension, improving measurement precision without significantly increasing system complexity
2Measurement precision
If ToF-based techniques are used for indoor localization, then the localization accuracy is improved, but the device complexity and cooperation requirements increase
Solution Approach 1:
The patent extracts and utilizes only the magnitude component of CSI data, separating it from the full CSI information that would be required for ToF measurements. This extraction approach allows the system to achieve improved accuracy similar to ToF methods while avoiding the complex protocol support and device cooperation requirements of full ToF implementation
Solution Approach 2:
The patent uses a simpler, less resource-intensive measurement approach (CSI magnitude) that provides accuracy benefits without requiring the extensive protocol support and device cooperation that ToF systems need. This 'cheaper' alternative achieves similar accuracy goals with reduced system complexity
3Measurement precision
If CSI-based models are used for position estimation, then the localization accuracy is improved, but the requirement for AP orientation information increases complexity and reduces reliability
Solution Approach 1:
The patent extracts only the magnitude component of CSI data, deliberately excluding the phase information that would be required for Angle of Arrival calculations. This extraction eliminates the need for AP orientation information, improving implementation reliability while maintaining enhanced accuracy through magnitude distance measurements
Solution Approach 2:
Instead of using CSI phase information to determine angle and position (which requires AP orientation), the patent inverts the approach by using CSI magnitude information. This alternative approach achieves position estimation without requiring knowledge of AP orientation, resolving the contradiction between accuracy improvement and implementation reliability
Data Source
AI summary
In one aspect, a system includes a station device configured to transmit a signal; multiple access point devices in connection with the station device, the multiple access point devices configured to receive the signal transmitted from the station device, wherein the multiple access point devices are configured to convert the signal into a measurable form; and a processing unit operably connected to the multiple access point devices. The processing unit is configured to, for each subcarrier within the signal received by the multiple access point devices, determine a measurement of channel state information including an overall shape of the signal; determine a magnitude distance for each subcarrier; and determine a location of the station device based on a fit of the magnitude distance to a model, wherein the model is based on an environment with one or more obstacles causing an obscuration of the signal.