Coordinated AP Ranging via Non-Overlapping Zones
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Solution Overview
Problem
Manual location of Access Points (APs) in a Wireless Local Area Network (WLAN) is error-prone and inefficient, leading to increased airtime overhead during ranging measurements between APs, as sequential ranging processes consume significant airtime.
Innovation Solution
Implement coordinated ranging between APs by assigning them to non-overlapping zones, allowing parallel ranging measurements within each zone, thereby reducing airtime overhead and minimizing interference between zones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sequential ranging measurements are performed between APs, then measurement precision can be maintained, but airtime overhead increases significantly
Solution Approach 1:
The patent divides the network into multiple non-overlapping zones, each handled by a different AP acting as a master. This segmentation allows parallel ranging measurements to occur simultaneously in different zones, reducing overall airtime overhead while maintaining measurement precision within each zone through dedicated master-slave coordination.
Solution Approach 2:
The patent combines multiple ranging measurement operations into parallel executions across different zones. By coordinating multiple master APs to simultaneously perform ranging with their respective slave APs in non-overlapping zones, the system achieves time compression without sacrificing measurement accuracy.
2Loss of time
If parallel ranging measurements are performed across all APs, then airtime overhead is reduced, but interference between measurements increases
Solution Approach 1:
The patent segments the network into non-overlapping zones to isolate interference. Each zone is assigned to a specific master AP, and the non-overlapping nature ensures that ranging measurements in different zones do not interfere with each other, as each zone operates in a spatially separated domain.
Solution Approach 2:
The patent applies local quality by assigning different spatial characteristics to different zones. Each zone is configured with specific master-slave AP pairs that operate independently in their local spatial domain, ensuring that interference remains localized and does not propagate across the entire network.
3Ease of manufacture
If manual location of APs is performed, then setup process can be completed, but error rate increases and efficiency decreases
Solution Approach 1:
The patent implements self-service by enabling APs to automatically perform ranging measurements with each other and compute their own locations. The master-slave coordination mechanism allows APs to autonomously exchange timing information and calculate distances without human intervention, eliminating manual configuration errors and improving both efficiency and reliability.
Solution Approach 2:
The patent uses feedback mechanisms where ranging measurement results are continuously exchanged between master and slave APs. The slave AP sends FTM requests and receives FTM indication messages containing timing information, which is then used to compute accurate locations. This automated feedback loop replaces error-prone manual processes with reliable algorithmic computation.
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 by enabling simultaneous ranging measurements across zones, improving the efficiency and accuracy of AP location determination within the network.
Implementation Method 1
The time of flight 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 coordinated ranging between APs in a network. Examples described herein may receive, by a computing device, neighbor adjacency information for a plurality of access points (APs) in a network, and based on the neighbor adjacency information, assign, by the computing device, subsets of the plurality of APs to non-overlapping zones. Examples described herein may initiate, by the computing device for each of the non-overlapping zones, ranging measurements between the subset of APs in the zone to generate a ranging result, wherein the ranging measurements between the subsets of APs in the non-overlapping zones are performed in parallel. Examples described herein may, based on the ranging results, resolve, by the computing device, locations of the plurality of APs.