On the sum rate and user fairness of STAR-RIS aided communications

Haochen Li; Xidong Mu; Yuanwei Liu; Yue Chen; Pan Zhiwen

doi:10.1109/LWC.2025.3537620

On the sum rate and user fairness of STAR-RIS aided communications

Haochen Li
, Xidong Mu
, Yuanwei Liu
, Yue Chen
, Pan Zhiwen

School of Electronics, Electrical Engineering and Computer Science

Research output: Contribution to journal › Article › peer-review

9 Citations (Scopus)

96 Downloads (Pure)

Abstract

A simultaneously transmitting and reflecting reconfigurable intelligent surface (STAR-RIS) aided communication system is investigated. A robust joint beamforming design problem under the imperfect channel state information (CSI) is formulated to maximize the weighted sum of the Jain’s fairness index and the normalized system sum rate. To solve this non-convex problem, an alternating optimization (AO) algorithm is proposed, which leverages the S-Procedure, successive convex approximation (SCA), and semidefinite relaxation (SDR). Simulation results demonstrate that with proposed algorithm: 1) various trade-offs between sum rate and user fairness can be achieved; 2) a larger trade-off region can be achieved by adopting STAR-RIS compared to conventional RIS; and 3) the performance degradation caused by imperfect CSI is less than 7% with our proposed robust beamforming approach.

Original language	English
Pages (from-to)	1306 - 1310
Journal	IEEE Wireless Communications Letters
Volume	14
Issue number	5
Early online date	31 Jan 2025
DOIs	https://doi.org/10.1109/LWC.2025.3537620
Publication status	Published - May 2025

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Keywords

STAR-RIS
STAR-RIS aided communications
sum rate

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10.1109/LWC.2025.3537620Licence: Unspecified

On the sum rate and user fairness of STAR-RIS aided communications
Copyright 2025 the authors. This is an accepted manuscript distributed under a Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium, provided the author and source are cited.
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Cite this

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abstract = "A simultaneously transmitting and reflecting reconfigurable intelligent surface (STAR-RIS) aided communication system is investigated. A robust joint beamforming design problem under the imperfect channel state information (CSI) is formulated to maximize the weighted sum of the Jain{\textquoteright}s fairness index and the normalized system sum rate. To solve this non-convex problem, an alternating optimization (AO) algorithm is proposed, which leverages the S-Procedure, successive convex approximation (SCA), and semidefinite relaxation (SDR). Simulation results demonstrate that with proposed algorithm: 1) various trade-offs between sum rate and user fairness can be achieved; 2) a larger trade-off region can be achieved by adopting STAR-RIS compared to conventional RIS; and 3) the performance degradation caused by imperfect CSI is less than 7\% with our proposed robust beamforming approach.",

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AU - Li, Haochen

AU - Mu, Xidong

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AB - A simultaneously transmitting and reflecting reconfigurable intelligent surface (STAR-RIS) aided communication system is investigated. A robust joint beamforming design problem under the imperfect channel state information (CSI) is formulated to maximize the weighted sum of the Jain’s fairness index and the normalized system sum rate. To solve this non-convex problem, an alternating optimization (AO) algorithm is proposed, which leverages the S-Procedure, successive convex approximation (SCA), and semidefinite relaxation (SDR). Simulation results demonstrate that with proposed algorithm: 1) various trade-offs between sum rate and user fairness can be achieved; 2) a larger trade-off region can be achieved by adopting STAR-RIS compared to conventional RIS; and 3) the performance degradation caused by imperfect CSI is less than 7% with our proposed robust beamforming approach.

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On the sum rate and user fairness of STAR-RIS aided communications

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