Passive MIMO Reflective Surface for NLOS Coverage and Positioning
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently determining the location of user equipment (UE) in non-line-of-sight scenarios, which affects the quality of service and coverage area.
Innovation Solution
The implementation of an array of reconfigurable reflective elements, comprising unit cells with radiating elements, power dividers, and phase shifting components, which can be controlled to reflect radio signals at desired angles, improving positioning accuracy and coverage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If active repeaters are used to extend coverage area, then coverage area is improved, but power consumption and device complexity increase
Solution Approach 1:
The patent introduces a passive reflecting surface as an intermediary element between the base station and user equipment. This surface reflects radio signals to extend coverage to non-line-of-sight areas without requiring active amplification, thereby avoiding the power consumption and complexity associated with active repeaters while still achieving coverage extension
Solution Approach 2:
The patent replaces the active electronic system (amplifiers, power supplies, control circuits in repeaters) with a passive electromagnetic reflection system. The reflecting surface uses controlled impedance variations to redirect signals without requiring external power, substituting a complex active system with a simpler passive one
2Area of stationary object
If active repeaters are used to extend coverage area, then coverage area is improved, but device complexity increases
Solution Approach 1:
The patent introduces a passive reflecting surface as an intermediary element between the base station and user equipment. This surface reflects radio signals to extend coverage to non-line-of-sight areas without requiring active amplification, thereby avoiding the power consumption and complexity associated with active repeaters while still achieving coverage extension
Solution Approach 2:
The patent replaces the active electronic system (amplifiers, power supplies, control circuits in repeaters) with a passive electromagnetic reflection system. The reflecting surface uses controlled impedance variations to redirect signals without requiring external power, substituting a complex active system with a simpler passive one
3Measurement precision
If conventional positioning methods are used, then positioning capability is provided, but positioning accuracy in non-line-of-sight conditions deteriorates
Solution Approach 1:
The patent divides the wireless coverage area into line-of-sight and non-line-of-sight regions, using the intelligent reflecting surface specifically to address the non-line-of-sight portion. This segmentation allows conventional positioning methods to work in direct paths while the reflecting surface provides additional signal paths for obscured locations, improving overall positioning reliability
Solution Approach 2:
The patent employs an intelligent reflecting surface that can dynamically adjust its reflection characteristics based on the spatial distribution of user equipment. By reconfiguring the surface in real-time, the system adapts to changing positioning requirements and maintains accuracy even as users move between line-of-sight and non-line-of-sight conditions
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 solution enhances the accuracy of UE location determination in non-line-of-sight conditions, reduces the need for active repeaters, and improves the quality of service by extending coverage area while minimizing power consumption and complexity.
Implementation Method 1
Each of the plurality of unit cells may be configured to reflect received radio signals at a desired angle
Implementation Method 2
a first phase shifting component electrically coupled to the first power divider and configured to provide a phase shift to a first polarized signal component
Implementation Method 3
a first power divider aligned to a first polarization and electrically coupled to a first phase shifting component
Data Source
AI summary
Designs and control techniques for passive Multiple-Input Multiple-Output (pMIMO) surfaces are provided. An example array of reconfigurable reflective elements includes a plurality of unit cells each comprising a cross-slot radiating element, a first varactor diode disposed across a first end of the cross-slot radiating element and configured to control polarization in a first plane, and a second varactor diode disposed across a second end of the cross-slot radiating element and configured to control polarization in a second plane, and a controller coupled to the first varactor diode and the second varactor diode and configured to provide control signals to the first varactor diode and the second varactor diode to vary a direction of a reflected signal.