Virtual Anchor Positioning for Wireless Terminals
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Solution Overview
Problem
Existing methods for determining the position of wireless communication devices indoors face challenges due to the inverse proportionality between distance and Received Signal Strength Indication (RSSI), leading to limited accuracy and susceptibility to multi-path fading issues, especially in crowded environments like train cabins or shopping malls.
Innovation Solution
A position estimation method that selects virtual anchors from mobile nodes closer to the target node, using their previously estimated positions to refine the position estimation iteratively, eliminating the need for additional fixed anchors and improving accuracy by reducing the distance between anchors and the target node.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If fixed base stations are used for position estimation, then the system structure is simple, but the distance between anchors and target node is large leading to low accuracy
Solution Approach 1:
The patent transforms the static anchor system into a dynamic one by allowing mobile nodes to serve as virtual anchors. The set of virtual anchors changes over time based on node movements and proximity to the target node, enabling the system to adaptively maintain high positioning accuracy without requiring a fixed infrastructure of closely-spaced base stations.
Solution Approach 2:
The patent creates virtual copies of anchor functionality by enabling mobile nodes to act as virtual anchors. Instead of requiring physical base stations at every location, the system replicates anchor capabilities across mobile nodes, allowing any node to provide positioning references for other nodes in the network.
2Measurement precision
If more fixed base stations are deployed to improve accuracy, then position estimation accuracy improves, but the cost and complexity of the system increases
Solution Approach 1:
The patent makes mobile nodes universal by enabling them to perform multiple functions: they serve as both positioning targets and positioning references (virtual anchors). This multi-functionality eliminates the need for dedicated base stations, as any mobile node can contribute to the positioning of others, thereby reducing the total number of required infrastructure elements.
Solution Approach 2:
The system enables nodes to position themselves using other nodes in the network without requiring external infrastructure. Mobile nodes autonomously participate in mutual positioning by serving as virtual anchors for nearby nodes, creating a self-sufficient positioning system that does not depend on deployed base stations.
3Ease of manufacture
If traditional fingerprinting method is used, then the method is simple to implement, but it is susceptible to multi-path fading issues in crowded environments
Solution Approach 1:
The patent replaces the static fingerprint database approach with a dynamic virtual anchor selection mechanism. Instead of relying on pre-recorded fingerprints that are vulnerable to environmental changes and multi-path effects, the system dynamically selects virtual anchors based on real-time proximity and signal quality, adapting to changing environmental conditions and reducing susceptibility to multi-path fading.
Data Source
AI summary
Conventional position estimation methods require the deployment of more fixed anchors in order to increase the accuracy in a crowded indoor environment, or they suffer from inaccuracies due to multipath fading. The present invention overcomes the problems associated with the prior arts by selecting one or more mobile nodes as virtual anchors when estimating the position of a target mobile node. This takes advantage of the fact that mobile nodes are closer to the target mobile node than the access points in most typical deployments, thus eliminating the need to deploy more access points or fixed anchors for the purpose of position determination. After obtaining an initial estimate of the position of the target mobile node, the target mobile node can serve as virtual anchors to estimate the positions of other mobile nodes, which can then be used to further refine the position estimate of the target mobile node.