Channel Assignment Permutations for WLAN Ranging
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Solution Overview
Problem
Existing ranging techniques in Wireless Local Area Networks (WLANs) face challenges such as increased airtime overhead during sequential ranging, inability to perform ranging during network topology changes without disrupting communications, and limited accuracy due to lack of consideration for multiple available channel assignments.
Innovation Solution
A computing device assigns multiple channels to Access Points (APs) based on channel assignment permutations and initiates ranging measurements during beacon intervals, ensuring that ranging measurements are performed on a threshold percentage of available links across these channels, thereby increasing accuracy and allowing for simultaneous or parallel ranging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sequential ranging is performed between APs, then ranging measurements can be completed, but airtime overhead increases
Solution Approach 1:
The patent segments the ranging process by assigning different channels to different AP pairs for simultaneous ranging measurements. Instead of sequential one-on-one ranging, multiple APs perform ranging in parallel on different channels during beacon intervals, dividing the overall ranging task across multiple frequency resources to reduce total airtime overhead.
Solution Approach 2:
The patent introduces a frequency dimension (multiple channels) to the ranging process. By utilizing multiple channels simultaneously during beacon intervals, the system transforms a time-sequential process into a parallel multi-channel process, effectively adding a frequency dimension to resolve the airtime overhead problem.
2Measurement precision
If ranging is performed during network topology changes, then location updates can be maintained, but communication disruptions occur
Solution Approach 1:
The patent utilizes periodic beacon intervals as designated time windows for ranging measurements. By confining ranging activities to these periodic intervals rather than continuous operation, the system ensures that location updates occur at regular intervals without interfering with ongoing communications, thus maintaining communication reliability while achieving location determination.
Solution Approach 2:
The patent performs ranging measurements in advance during beacon intervals before network topology changes take effect. By completing ranging measurements proactively during these scheduled intervals, the system ensures location information is updated before disruptions occur, maintaining location accuracy without compromising communication continuity.
3Device complexity
If single channel assignment is used for ranging, then channel configuration is simple, but ranging accuracy is limited
Solution Approach 1:
The patent changes the channel parameter by assigning multiple channels to different APs based on permutations rather than a single fixed channel. This parameter change enables the system to exploit frequency diversity for improved ranging accuracy, as different channels experience different propagation conditions, while the permutation approach systematically manages the complexity of multi-channel configuration.
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 reduces airtime overhead, enables ranging during network topology changes without disrupting communications, and enhances ranging accuracy by utilizing multiple available channel assignments, leading to more precise AP location determination.
Implementation Method 1
The time of flight (ToF) can be defined as the overall time taken by signals to propagate from the AP to a client device (say, the communication device), and back to the AP from the client device. From the time of flight information, a distance between the AP and the client device may be determined.
Data Source
AI summary
Examples described herein provide channel assignments for ranging between network devices in a network during beacon intervals. Examples described herein may assign a plurality of channels to a plurality of network devices based on a plurality of channel assignment permutations, and initiate, during beacon intervals, ranging measurements between the plurality of network devices on the plurality of channels based on each of the channel assignment permutations to generate ranging results. Examples described herein may determine whether total ranging measurements are performed for a threshold percentage of available links between the plurality of network devices on the plurality of channels, wherein the total ranging measurements include the ranging measurements based on each of the channel assignment permutations. Examples described herein may, based on a determination that the total ranging measurements are performed for the threshold percentage of available links, resolve locations of the plurality of APs based on the ranging results.