Client Location Determination Using Neighboring Access Points
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Solution Overview
Problem
Existing methods for determining the location of a wireless client device in a wireless local area network are inadequate when there are less than three wireless access points available to receive signal strength information, as this is insufficient for accurate location determination.
Innovation Solution
The technique involves sending a beacon report request action frame to a wireless client device, causing it to transmit a broadcast probe request frame that is received by multiple access points, including both known and unknown ones, and using the signal strength information from probe response frames to determine the client device's location, even if not all access points are part of the same WLAN.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If location determination uses only access points within the same WLAN, then network security and management are simplified, but location accuracy deteriorates when fewer than three access points are available
Solution Approach 1:
The system makes the location determination mechanism universal by enabling access points from different WLANs to participate in the same location calculation process. The serving access point can retrieve signal strength information from non-network access points (those outside the WLAN) and combine them with information from network access points, allowing the location determination function to work reliably regardless of how many access points are within the same network boundary.
2Measurement precision
If the system retrieves signal strength information from non-network access points, then location determination accuracy improves, but system complexity and information security requirements increase
Solution Approach 1:
The serving access point acts as an intermediary that mediates between the location determination need and the distributed access points in the environment. Instead of requiring direct communication between client devices and multiple access points, or complex coordination among multiple access points, the serving access point centralizes the process by retrieving signal strength information from various access points (including non-network ones) and performing the location calculation itself, thereby simplifying the overall system architecture while improving measurement precision.
3Measurement precision
If three or more access points are required for location determination, then triangulation accuracy improves, but the system becomes inoperative when fewer access points are available in coverage areas
Solution Approach 1:
The system expands the spatial dimension of available access points by breaking down the traditional WLAN boundary constraint. Instead of limiting the search for signal strength information to access points within the same network (a logical dimension), the system accesses the physical dimension of all nearby access points regardless of network affiliation. This dimensional expansion ensures that three or more access points are available for triangulation in virtually any coverage area, maintaining both accuracy and productivity.
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 method allows for accurate location determination of a wireless client device using signal strength information from three or more access points, including those outside the client's serving WLAN, thereby overcoming the limitation of insufficient access points within the same network.
Implementation Method 1
signal strength information contained in the one or more probe response frames sent by the one or more wireless access points and which signal strength information indicates the signal strength observed by the one or more wireless access points with respect to the broadcast probe request frame transmitted by the wireless client device
Data Source
AI summary
Techniques are presented to determine a location of a wireless client device operating in a wireless local area network. A beacon report request action frame is sent to a wireless client device, where the request frame is configured to cause the wireless client device to transmit a broadcast probe request frame. A beacon report response message is received from the wireless client device and includes one or more probe response frames transmitted by one or more wireless access points that receive the broadcast probe request frame. The wireless client device location is determined based in part on signal strength information in the probe response frames sent by the one or more wireless access points and which signal strength information indicates the signal strength observed by the one or more wireless access points with respect to the broadcast probe request frame transmitted by the wireless client device.