Wireless Sensor Node Localization via Time of Flight and Channel State Information
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Solution Overview
Problem
Existing wireless sensor network localization technologies face challenges in indoor environments due to reliability issues, high deployment costs, and inaccuracies caused by multipath effects and signal attenuation, which affect the accuracy and effectiveness of location determination.
Innovation Solution
The system employs a combination of time of arrival measurements with techniques to mitigate multipath issues and sampling limitations, combined with triangulation methods using maximum likelihood estimation to achieve highly accurate ranging and location determination, even in complex indoor environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional wireless sensor network localization methods are used in indoor environments, then deployment is simpler, but accuracy deteriorates due to multipath effects and signal attenuation
Solution Approach 1:
The system segments the localization problem into multiple independent measurements from different anchor nodes. Each anchor node independently measures time of arrival and channel state information, and the final location is determined by combining these segmented measurements through triangulation, which improves accuracy while maintaining reliability in multipath environments
Solution Approach 2:
The patent introduces channel state information (CSI) as an intermediary parameter between the physical signal propagation and location determination. CSI serves as a mediator that captures multipath characteristics, allowing the system to compensate for signal degradation and improve both accuracy and reliability of location detection
2Measurement precision
If more anchor nodes are deployed to improve triangulation accuracy, then location determination precision improves, but deployment cost increases
Solution Approach 1:
The anchor nodes are designed with multi-functionality, serving both as location references and as signal sources for time of arrival and channel state information measurements. This universal design allows the same infrastructure to support multiple measurement types without additional deployment complexity, achieving high accuracy with minimal nodes
Solution Approach 2:
The system changes the measurement parameters from simple signal presence detection to precise time of arrival and channel state information measurement. This parameter transformation enables accurate location determination with fewer anchor nodes, reducing deployment complexity while maintaining high measurement precision
3Measurement precision
If time of arrival measurements are used for ranging, then location accuracy improves, but hardware delays and synchronization requirements increase system complexity
Solution Approach 1:
The system performs preliminary hardware delay calibration and synchronization before actual location measurements. By pre-characterizing the hardware delays of each anchor node and storing these as compensation values, the system eliminates the need for complex real-time calibration during operation, maintaining high ranging accuracy while reducing operational complexity
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 provides improved accuracy and reliability in locating wireless sensor nodes within indoor environments, reducing errors and costs associated with infrastructure deployment while maintaining long communication distances and good battery life for sensor nodes.
Implementation Method 1
determine a round trip time estimate of the first and second packets
Implementation Method 2
RF circuitry for transmitting and receiving communications in the wireless network architecture including a first RF signal
Data Source
AI summary
Systems, apparatuses, and methods for determining locations of wireless nodes in a network architecture are disclosed herein. In one example, a system includes a first wireless node having a wireless device with one or more processing units and RF circuitry for transmitting and receiving communications in the wireless network architecture including a first RF signal having a first packet. A second wireless node having a wireless device with a transmitter and a receiver enables bi-directional communications with the first wireless node in the wireless network architecture including a second RF signal with a second packet. The one or more processing units of the first wireless node are configured to execute instructions to determine a round trip time estimate of the first and second packets, to determine channel state information (CSI) of the first and second wireless nodes, and to calibrate hardware to determine hardware delays of the first and second wireless nodes.