RIS Selection for Multipath Fading Equalization
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Solution Overview
Problem
Wireless communications systems face challenges in efficiently addressing multipath fading, which leads to energy-intensive and computationally expensive equalization procedures at receiving devices, particularly in scenarios involving reconfigurable intelligent surfaces (RIS) and user equipment (UE) communication links.
Innovation Solution
The system employs a reconfigurable intelligent surface (RIS) selection method where a network entity chooses an RIS close to the UE to perform over-the-air equalization, allowing the UE to omit or simplify equalization procedures by compensating for multipath fading, and includes a reference signal measurement mechanism to determine the link's flatness, enabling energy-saving modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE performs equalization procedures to compensate for multipath fading, then the communication reliability is improved, but the energy consumption and computational complexity increase
Solution Approach 1:
The patent introduces a reconfigurable intelligent surface (RIS) as an intermediary between the network entity and the UE. The RIS performs equalization procedures instead of the UE by adjusting the phase of reflected signals to compensate for multipath fading. This transfers the computational burden from the UE to the RIS, maintaining communication reliability while reducing UE energy consumption.
2Reliability
If the UE performs equalization procedures to compensate for multipath fading, then the communication reliability is improved, but the computational complexity increases
Solution Approach 1:
The RIS acts as a mediator that performs the computationally intensive equalization procedures. The network entity configures the RIS with appropriate phase shift values, and the RIS applies these configurations to reflected signals. This eliminates the need for the UE to perform complex equalization calculations, significantly reducing UE computational complexity while maintaining signal quality.
3Use of energy by moving object
If the network entity configures RIS to perform equalization, then the UE energy consumption is reduced, but the device complexity at network entity increases
Solution Approach 1:
The network entity performs preliminary actions by calculating the optimal phase shift configurations for the RIS based on channel state information. The network entity sends these pre-computed configurations to the RIS, which then applies them automatically. This preliminary computation at the network entity simplifies the ongoing operation and reduces the complexity burden during actual communication.
Solution Approach 2:
The system implements feedback mechanisms where the UE measures reference signals and reports channel conditions to the network entity. The network entity uses this feedback to adjust and optimize the RIS configurations, ensuring that the equalization remains effective while adapting to changing channel conditions. This feedback loop enables automated optimization without requiring complex real-time processing at the UE.
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. For example, described techniques provide for performing multipath fading equalization at a reconfigurable intelligent surface (RIS), allowing a receiving device to omit an equalization procedure or to perform a simpler equalization. A transmitting device, such as a network entity, may select a RIS that is within a sufficient proximity to a receiving device, such as a user equipment (UE), that multipath fading of the RIS to receiver wireless link is likely to be below a threshold. The network entity may configure the selected RIS with a phase matrix to perform over-the-air equalization to compensate for multipath fading over the network entity to RIS wireless link. The UE may omit an equalization procedure or may perform a simpler equalization procedure as compared to a scenario where the RIS does not compensate for multipath fading.