University of Oulu

N. T. Nguyen, V. . -D. Nguyen, Q. Wu, A. Tölli, S. Chatzinotas and M. Juntti, "Hybrid Active-Passive Reconfigurable Intelligent Surface-Assisted Multi-User MISO Systems," 2022 IEEE 23rd International Workshop on Signal Processing Advances in Wireless Communication (SPAWC), 2022, pp. 1-5, doi: 10.1109/SPAWC51304.2022.9833956.

Hybrid active-passive reconfigurable intelligent surface-assisted multi-user MISO systems

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Author: Nguyen, Nhan T.1; Nguyen, V.-Dinh2; Wu, Qingqing3;
Organizations: 1Centre for Wireless Communications, University of Oulu, Finland
2Interdisciplinary Centre for Security, Reliability and Trust (SnT), University of Luxembourg, Luxembourg
3State Key Laboratory of Internet of Things for Smart City, University of Macau, Macau, China
Format: article
Version: accepted version
Access: open
Online Access: PDF Full Text (PDF, 0.5 MB)
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Language: English
Published: Institute of Electrical and Electronics Engineers, 2022
Publish Date: 2023-01-09


We consider a multi-user multiple-input single-output (MISO) communications system which is assisted by a hybrid active-passive reconfigurable intelligent surface (RIS). Unlike conventional passive RISs, hybrid RIS is equipped with a few active elements with the ability to reflect and amplify incident signals to significantly improve the system performance. Towards a fairness-oriented design, we maximize the minimum rate among all users through jointly optimizing the transmit beamforming vectors and RIS reflecting/amplifying coefficients. Combining tools from block coordinate ascent and successive convex approximation, the challenging nonconvex problem is efficiently solved by a low-complexity iterative algorithm. The numerical results show that a hybrid RIS with 4 active elements out of a total of 50 elements with a power budget of −1 dBm offers an improvement of up to 80% to the considered system, while that achieved by a fully passive RIS is only 27%.

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Series: IEEE International Workshop on Signal Processing Advances in Wireless Communications
ISSN: 2325-3789
ISSN-L: 2325-3789
ISBN: 978-1-6654-9455-7
ISBN Print: 978-1-6654-9456-4
Pages: 1 - 5
DOI: 10.1109/spawc51304.2022.9833956
Host publication: 2022 IEEE 23rd International Workshop on Signal Processing Advances in Wireless Communication (SPAWC), 04-06 July 2022, Oulu, Finland
Conference: IEEE International Workshop on Signal Processing Advances in Wireless Communication
Type of Publication: A4 Article in conference proceedings
Field of Science: 213 Electronic, automation and communications engineering, electronics
Funding: This research has been supported in part by the Academy of Finland, 6G Flagship program under Grant 346208, EERA Project under grant 332362, and Infotech Program funded by University of Oulu Graduate School.
Academy of Finland Grant Number: 346208
Detailed Information: 346208 (Academy of Finland Funding decision)
332362 (Academy of Finland Funding decision)
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