RIS Near-Field Positioning for Accurate Indoor Mobile Location
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Solution Overview
Problem
Existing wireless communication systems face challenges in accurately determining the position of mobile devices when Reconfigurable Intelligent Surfaces (RIS) are in close proximity, as near-field effects are not adequately considered, which can occur indoors where RISs improve network coverage.
Innovation Solution
A method and device for determining RIS-assisted mobile device positioning that accounts for near-field operational distances by measuring RF signals reflected from RISs, using a transceiver, processing units, and conducting positioning sessions based on relative distances to determine the mobile device's position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If RISs are deployed in close proximity to mobile devices to improve indoor network coverage, then network coverage and signal availability are improved, but near-field effects cause positioning measurement errors and reduce positioning accuracy
Solution Approach 1:
The patent applies parameter changes by detecting whether the mobile device is in the near-field or far-field region of the RIS and adjusting the positioning measurement parameters accordingly. When near-field conditions are detected, the system uses near-field channel models and processing techniques; when far-field conditions are detected, conventional far-field positioning methods are used. This dynamic parameter adjustment resolves the contradiction by adapting the measurement approach to the actual propagation conditions, thereby maintaining positioning accuracy while allowing RIS deployment in close proximity for improved coverage.
2Device complexity
If conventional positioning methods are used assuming far-field conditions, then positioning processing is simplified, but positioning accuracy deteriorates when mobile devices are in near-field regions of RISs
Solution Approach 1:
The system dynamically changes positioning parameters based on detected field conditions. A determination module identifies whether the mobile device is in near-field or far-field region, and based on this detection, the system selects appropriate channel models and measurement techniques. This conditional parameter switching maintains simplicity in far-field scenarios while enabling accurate near-field processing when needed, thus resolving the contradiction between processing complexity and positioning accuracy.
Solution Approach 2:
The patent creates separate positioning processing paths for near-field and far-field conditions. Instead of using a single complex unified model, the system implements distinct channel models and measurement procedures for each field region. This copying approach allows the system to use simplified far-field methods when applicable while having dedicated near-field processing capabilities available when needed, balancing complexity and accuracy.
3Ease of operation
If near-field effects are ignored in positioning measurements, then positioning system design and operation is simpler, but positioning reliability deteriorates in indoor environments with close-proximity RISs
Solution Approach 1:
The system performs preliminary detection of near-field conditions before conducting positioning measurements. The determination module assesses whether the mobile device is in the near-field region of any RIS, and based on this preliminary assessment, the system proactively selects the appropriate measurement and processing approach. This preliminary action prevents reliability issues by ensuring the correct model is used before measurements are taken, while maintaining ease of operation through automated detection and selection without requiring manual intervention.
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
Enhances the accuracy and availability of mobile device positioning by considering near-field effects, improving location estimation in environments with RISs in close proximity to the mobile device.
Implementation Method 1
measurements made by the mobile device of radio frequency (RF) signals reflected from at least one RIS
Data Source
AI summary
Techniques for determining reconfigurable intelligent surface (RIS) operation for RIS-assisted position determination of a mobile device in a wireless communications system, according to this disclosure, may comprise determining, for one or more RISs, whether the mobile device is within a near-field operational distance of the RIS based at least in part on a determined near-field operational distance of the RIS, and a relative distance between the mobile device and the RIS. Techniques may also comprise determining an RIS-assisted position of the mobile device based on measurements made by the mobile device of radio frequency (RF) signals reflected from at least one RIS of the one or more RISs. Techniques may also comprise providing the determined RIS-assisted position of the mobile device.