Model-Free Optimization and Experimental Validation of RIS-Assisted Wireless Communications Under Rich Multipath Fading

Chen, Tianrui; You, Minglei; Zhang, Yangyishi; Zheng, Gan; Gros, Jean Baptiste; Lerosey, Geoffroy; Nasser, Youssef; Burton, Fraser; Gradoni, Gabriele

Abstract

Reconfigurable intelligent surface (RIS) devices have emerged as an effective way to control the propagation channels for enhancing the end-users' performance. However, RIS optimization involves configuring the radio frequency response of a large number of radiating elements, which is challenging in real-world applications due to high computational complexity. In this paper, a model-free cross-entropy (CE) algorithm is proposed to optimize the binary RIS configuration for improving the signal-to-noise ratio (SNR) at the receiver. One key advantage of the proposed method is that it only requires system performance indicators, e.g., the received SNR, without the need for channel models or channel state information. Both simulations and experiments are conducted to evaluate the performance of the proposed CE algorithm. This study provides an experimental demonstration of the channel hardening effect in a multi-antenna RIS-assisted wireless system under rich multipath fading.

Citation

Chen, T., You, M., Zhang, Y., Zheng, G., Gros, J. B., Lerosey, G., Nasser, Y., Burton, F., & Gradoni, G. (2024). Model-Free Optimization and Experimental Validation of RIS-Assisted Wireless Communications Under Rich Multipath Fading. IEEE Wireless Communications Letters, 13(3), 627-631. https://doi.org/10.1109/lwc.2023.3337709

• Journal Article Type: Article
• Acceptance Date: Nov 24, 2023
• Online Publication Date: Nov 29, 2023
• Publication Date: 2024-03
• Deposit Date: Nov 27, 2023
• Publicly Available Date: Nov 30, 2023
• Journal: IEEE Wireless Communications Letters
• Print ISSN: 2162-2337
• Electronic ISSN: 2162-2345
• Publisher: Institute of Electrical and Electronics Engineers
• Peer Reviewed: Peer Reviewed
• Volume: 13
• Issue: 3
• Pages: 627-631
• DOI: https://doi.org/10.1109/lwc.2023.3337709
• Keywords: Reconfigurable intelligent surface (RIS); Phase shifts optimization; Cross-entropy algorithm; Channel hardening
• Public URL: https://nottingham-repository.worktribe.com/output/27859601
• Publisher URL: https://ieeexplore.ieee.org/document/10333087