RIS Energy Steering for Obstructed RF Harvesting Coverage
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Solution Overview
Problem
Current communication systems face challenges in efficiently harnessing and directing ambient electromagnetic radiation for energy harvesting, especially in the presence of obstacles, due to the random and uncontrollable nature of wireless propagation environments and the need to support phase adjustments across different frequency bands simultaneously.
Innovation Solution
A reconfigurable intelligent surface (RIS) with active and passive elements that can measure electromagnetic radiation levels across various frequency ranges, report energy levels to a network node, and steer energy towards energy harvesting devices based on these measurements, allowing for robust energy harvesting even in obstructed areas by forming groups of passive elements and performing beam refinement procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If passive elements are used for energy harvesting, then hardware cost and energy consumption are reduced, but the ability to control and steer electromagnetic radiation is insufficient
Solution Approach 1:
The RIS is divided into multiple passive elements that can be independently controlled by active elements. Each passive element can be individually configured to reflect or transmit electromagnetic waves, enabling precise control while maintaining the overall low-power architecture of passive components
Solution Approach 2:
Active elements serve as intermediaries between the control system and passive elements. These active elements consume minimal energy to configure the passive elements, which then perform the main energy harvesting function passively, resolving the contradiction between control capability and energy consumption
2Device complexity
If the wireless propagation environment is left random and uncontrollable, then system complexity is reduced, but energy harvesting efficiency deteriorates in the presence of obstacles
Solution Approach 1:
The RIS configuration is made dynamic and reconfigurable, allowing the system to adapt to changing propagation conditions and obstacle positions. The passive elements can be dynamically adjusted to steer electromagnetic radiation toward energy harvesting devices, improving efficiency without requiring a completely complex controllable system
Solution Approach 2:
The system changes the reflection characteristics of passive elements by adjusting their electrical parameters (such as impedance or phase shift) through the active elements. This allows control over the propagation environment by modifying electromagnetic wave parameters rather than physically moving components, balancing complexity and efficiency
3Adaptability or versatility
If phase adjustments are made across different frequency bands simultaneously, then adaptability is improved, but device complexity increases
Solution Approach 1:
The passive elements are designed to operate across multiple frequency bands simultaneously, providing universal functionality. The same passive structure can handle different frequencies without requiring separate control mechanisms for each band, reducing complexity while maintaining adaptability
Solution Approach 2:
Different groups of passive elements can be configured with different local characteristics optimized for specific frequency ranges. The active elements can selectively activate specific groups based on the operating frequency, allowing frequency-specific optimization without controlling all elements across all frequencies, thus managing 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
The RIS enables effective energy harvesting by selectively steering electromagnetic radiation towards energy harvesting devices, improving coverage and efficiency in environments with obstacles, while maintaining low hardware costs and energy consumption.
Implementation Method 1
steering, by the reconfigurable intelligent surface energy based on the at least one request message, the harvested electromagnetic radiation towards at least one energy harvesting device
Data Source
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AI summary
A reconfigurable intelligent surface (RIS) in a radio network includes a plurality of passive elements which are controlled by a plurality of active elements distributed among the plurality of passive elements, wherein the plurality of active elements configure the reconfigurable intelligent surface to perform, based on at least one request message, at least one of sensing incident electromagnetic radiation harvested over at least one frequency range by the passive elements; and steering energy of the harvested electromagnetic radiation towards at least one energy harvesting device in the radio network. A network node is configured to select at least one reconfigurable intelligent surface in a radio network; and send at least one request message to the selected reconfigurable intelligent surface to cause the reconfigurable intelligent surface to steer harvested electromagnetic radiation within at least one frequency range toward at least one energy harvesting device in the radio network.