WLAN Access Point Movement Detection via Multipath Feedback
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Solution Overview
Problem
Current WLAN chipsets lack the functionality to detect physical activity in environments due to the additional cost and power consumption associated with implementing Doppler shift detection, which is essential for security surveillance but not feasible within cost and power constraints.
Innovation Solution
Access points in WLANs leverage their radio frequency capabilities to detect physical activities by measuring changes in the multipath environment through feedback information from client devices, determining changes in multipath parameters to infer movement without requiring additional hardware, thus conserving power and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If specialized hardware components are added to detect Doppler shifts, then movement detection capability is improved, but device cost and power consumption increase
Solution Approach 1:
The access point uses its existing radio frequency transceiver for dual purposes: both for standard WLAN communication and for detecting multipath environment changes that indicate movement. By making the communication hardware multi-functional, no additional specialized hardware is needed, thus avoiding increased power consumption and cost while maintaining movement detection capability
Solution Approach 2:
The system uses the feedback information already being exchanged for communication purposes to also serve movement detection. The client devices' feedback about signal reception, which is necessary for communication, is simultaneously utilized to detect changes in the multipath environment, making the system self-sufficient without requiring additional dedicated detection resources
2Measurement precision
If specialized hardware components are added to detect Doppler shifts, then movement detection capability is improved, but device cost increases
Solution Approach 1:
The access point uses its existing radio frequency transceiver for dual purposes: both for standard WLAN communication and for detecting multipath environment changes that indicate movement. By making the communication hardware multi-functional, no additional specialized hardware is needed, thus avoiding increased device cost while maintaining movement detection capability
Solution Approach 2:
Instead of using specialized hardware to directly detect movement, the system creates an indirect measurement by analyzing changes in the radio frequency multipath environment. This informational copy of movement data is extracted from existing communication signals, avoiding the need for expensive specialized detection hardware
3Measurement precision
If additional hardware components are added to the WLAN chipset, then movement detection functionality is improved, but basic functionalities may be sacrificed
Solution Approach 1:
The access point uses its existing radio frequency transceiver for dual purposes: both for standard WLAN communication and for detecting multipath environment changes that indicate movement. This approach ensures that basic communication functionalities are maintained while adding movement detection capability, as no hardware is removed or compromised
Solution Approach 2:
The movement detection function is merged with the existing WLAN communication function. The same radio frequency transceiver and signal processing infrastructure are used for both purposes, combining multiple functions into a unified system that maintains all basic functionalities while adding enhanced capability
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 enables the detection of physical activities within the WLAN coverage area, determining the type and extent of movement, while maintaining power efficiency and avoiding the need for specialized hardware, thereby enhancing security surveillance capabilities.
Implementation Method 1
measuring changes in the multipath environment through feedback information from client devices
Data Source
AI summary
The present disclosure discloses a method and network device for detecting movement in a physical environment. Specifically, a network device obtains a first feedback information for a first set of wireless signals transmitted by a first device in a physical environment and received by a second device in the physical environment. Moreover, the network device obtains a second feedback information for a second set of wireless signals transmitted by the first device and received by the second device. The network device then compares the first feedback information to the second feedback information to identify a first set of one or more difference values. Based on the first set of one or more difference values, the network device determines that one or more physical entities within the physical environment have moved.