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Published on: February 12, 2014
Multi-user frequency selective beam steering by reconfigurable intelligent surfaces in the Ka-band
Lukas Mueller1, Alexander Wolff2, Steffen Klingel1
1Department of Electrical and Computer Engineering and Research Center OPTIMAS, RPTU Kaiserslautern-Landau, Kaiserslautern, D-67663, Germany.
Scientific Reports
|March 29, 2025
Summary
This study introduces multi-user frequency selective beam steering (MU-FSBS) using reconfigurable intelligent surfaces (RIS). MU-FSBS significantly boosts channel capacity compared to traditional TDMA methods in wireless communications.
Area of Science:
- Wireless Communication
- Metamaterials
- Machine Learning
Background:
- Reconfigurable intelligent surfaces (RIS) are emerging technologies for enhancing wireless communication coverage at millimeter-wave frequencies.
- Traditional multi-user communication methods like time division multiple access (TDMA) face limitations in spectral efficiency and capacity.
Purpose of the Study:
- To design and fabricate a novel reconfigurable intelligent surface (RIS) for multi-user frequency selective beam steering (MU-FSBS).
- To demonstrate the capability of MU-FSBS to achieve higher channel capacity than TDMA in multi-user scenarios.
- To investigate the application of a neural network-based machine learning architecture for optimizing RIS performance.
Main Methods:
- A varactor diode-tuned RIS was designed and fabricated to enable independent beam steering in the Ka-band.
- A customized neural network-based machine learning architecture was implemented to optimize RIS bias voltage patterns for multi-frequency beam steering.
- Experimental validation involved steering beams at 27 GHz and 31 GHz to specific angles.
Main Results:
- Independent beam steering of normally incident beams at 27 GHz and 31 GHz was achieved with deflection angles ranging from 10° to 45°.
- The MU-FSBS approach demonstrated an average channel capacity increase of approximately 50% compared to TDMA at a 20 dB SNR.
- A significant channel capacity increase of 84% was observed for MU-FSBS over TDMA at a 60 dB SNR.
Conclusions:
- The developed MU-FSBS technique using a varactor diode-tuned RIS and a neural network controller significantly enhances channel capacity in multi-user wireless communication.
- This approach offers a promising alternative to TDMA, particularly in high SNR environments, by enabling simultaneous, independent beam steering across multiple frequencies.
- The findings highlight the potential of intelligent surfaces and machine learning for future high-capacity wireless systems.
