UWB Node Localization via Indirect Path Reflections
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Solution Overview
Problem
Existing wireless body network location techniques do not effectively utilize ultra-wideband (UWB) multi-path diversity, relying solely on direct paths or secondary paths without accurately incorporating the characteristics of UWB channels, leading to inaccurate positioning and increased radio linkups in cooperative body area networks.
Innovation Solution
A method that measures the time of flight of indirect UWB signals from single reflections on surfaces like the ground or ceiling to supplement or substitute direct path measurements, enabling accurate positioning of wireless communication nodes within body area networks by utilizing the reproducible components of the UWB multi-path channel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If direct path measurements are used for location, then the method is simple, but positioning accuracy deteriorates when direct paths are unavailable
Solution Approach 1:
The patent introduces indirect paths (reflected signals) as intermediary elements to enable location measurements when direct paths are unavailable. By using reflections from surfaces (walls, ceiling, floor) as intermediaries to carry location information, the system maintains positioning capability in NLOS conditions without requiring direct line-of-sight between nodes.
Solution Approach 2:
The patent changes the measurement parameter from direct path time-of-flight to indirect path time-of-flight. By measuring the time of flight of reflected signals and using the known reflection geometry, the system derives location information from indirect measurements, transforming the measurement approach to work in NLOS environments.
2Measurement precision
If multiple radio linkups are performed to improve location accuracy, then positioning precision improves, but system complexity increases
Solution Approach 1:
The patent applies partial action by utilizing only the necessary indirect path measurements to achieve accurate positioning. Instead of requiring multiple direct path linkups, the system uses a limited set of indirect measurements from reflected signals to derive sufficient location information, reducing the number of required radio linkups while maintaining accuracy.
Solution Approach 2:
The patent makes the location system universal by enabling it to function in both LOS and NLOS conditions through a unified approach that handles both direct and indirect paths. The same location algorithm can process both direct time-of-flight measurements and indirect reflected path measurements, eliminating the need for separate handling of different propagation conditions.
3Measurement precision
If indirect paths are used for location, then positioning accuracy in NLOS improves, but measurement complexity increases
Solution Approach 1:
The patent extracts the time-of-flight information from the complex multi-path signal environment by identifying and isolating the indirect path components. By separating the reflected signal paths from the direct path and extracting their temporal characteristics, the system obtains measurable location data even in complex NLOS environments with multiple reflections.
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 improves the accuracy of node positioning in wireless body networks by leveraging UWB multi-path diversity, reducing the number of necessary radio linkups and providing both absolute and relative positioning without requiring direct paths, thus enhancing the precision and efficiency of location determination.
Implementation Method 1
performing at least one measurement of time of flight of an indirect path of ultra wideband signal transmitted between the first node and the second node
Implementation Method 2
said path arising from a single reflection on a surface external to said body
Data Source
AI summary
A method and a system are provided which are able to utilize indirect paths of signals of UWB type to locate a wireless communication node possessed by a body. The present method and system can notably apply to cooperative body networks implementing several wireless nodes able to communicate with one another.