RIS Side-lobe Suppression via Time-varying Control
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Solution Overview
Problem
Reconfigurable intelligent surfaces (RIS) in wireless communication systems face challenges in managing interference due to sidelobes, which can adversely affect communication quality and accuracy, especially when they lack independent amplitude control and have limited phase reflection coefficients, leading to quantization errors and prominent sidelobe levels.
Innovation Solution
Configuring RIS with time-varying control parameters for side-lobe suppression, including amplitude tapering and dithering based on time offsets, and using parameterized codebooks to set RIS configurations that reduce sidelobe levels, while also enabling UE power control to mitigate interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If RIS uses fixed phase reflection coefficients with limited resolution, then device complexity is reduced, but sidelobe levels increase and communication accuracy deteriorates
Solution Approach 1:
The patent applies dynamics by transitioning from fixed phase reflection coefficients to time-varying control parameters. The RIS configuration changes dynamically over time through periodic updates, allowing the system to adapt to varying communication conditions and suppress sidelobe interference without requiring complex independent amplitude control for each element.
Solution Approach 2:
The patent changes the parameter resolution from limited fixed phase values to time-varying parameters with higher effective resolution. By using periodic time-varying control configurations, the system achieves finer control over the RIS reflection characteristics, reducing quantization errors and sidelobe levels while maintaining manageable device complexity.
2Object-generated harmful factors
If RIS employs time-varying control for side-lobe suppression, then sidelobe interference is reduced, but device complexity and control overhead increase
Solution Approach 1:
The patent implements periodic action by using time-varying control parameters that change periodically. The RIS configuration is updated at regular intervals, creating a periodic control mechanism that effectively suppresses sidelobe interference through temporal modulation while avoiding the need for continuous complex control adjustments.
Solution Approach 2:
The system introduces dynamic control through time-varying parameters that adapt the RIS behavior over time. This dynamic approach allows the system to respond to changing communication conditions and suppress sidelobe effects without requiring static complex control structures, balancing performance improvement with manageable complexity.
3Device complexity
If RIS lacks independent amplitude control, then device complexity is reduced, but sidelobe suppression capability deteriorates
Solution Approach 1:
The patent introduces time-varying control parameters as an intermediary mechanism that mediates between the limited hardware capabilities and the need for effective sidelobe suppression. This intermediary control layer enables sophisticated interference management without requiring direct independent amplitude control for each RIS element, maintaining a balance between complexity and performance.
Solution Approach 2:
The system uses parameter changes through time-varying control to achieve effective sidelobe suppression despite lacking independent amplitude control. By dynamically adjusting control parameters over time, the system compensates for the hardware limitations and achieves interference reduction that would otherwise require more complex amplitude control capabilities.
Data Source
AI summary
Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a network node may transmit, to a reconfigurable intelligent surface (RIS), information identifying a RIS configuration, wherein the RIS configuration includes one or more parameters for a time-varying control configuration associated with side-lobe suppression. The network node may communicate, via the RIS and using the RIS configuration, with a user equipment (UE). Numerous other aspects are described.