Safeguarding NOMA Networks via Reconfigurable Dual-Functional Surface Under Imperfect CSI

Wang, Wen; Ni, Wanli; Tian, Hui; Yang, Zhaohui; Huang, Chongwen; Wong, Kai-Kit

doi:10.1109/jstsp.2022.3175013

Cited by 27 publications

(9 citation statements)

References 56 publications

(97 reference statements)

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“…However, the accurate CSI can be obtained via multiple channel estimation algorithms investigated in the literature for IRS-enabled systems [36]- [39]. Additionally, the proposed framework can be exploited further with an imperfect CSI scenario [40].…”

Section: System Model and Problem Formulation A Irs-aided Phase Coope...mentioning

confidence: 99%

System throughput maximization in IRS-assisted phase cooperative NOMA networks

Sadia

Hassan

Abbas

et al. 2023

Physical Communication

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Section: System Model and Problem Formulation A Irs-aided Phase Coope...mentioning

confidence: 99%

System throughput maximization in IRS-assisted phase cooperative NOMA networks

Sadia

Hassan

Abbas

et al. 2023

Physical Communication

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“…Considering that the acquired CSI is coarse and outdated, we adopt the bounded CSI model to characterize the uncertainties of CSI, given by [32] h…”

Section: A Problem Formulation Under Imperfect Csimentioning

confidence: 99%

“…Similar to the transformation of constraint (32), we here adopt the penalty function-based method to address constraint (59b). By introducing an auxiliary variable η m = α 2 m β m , we obtain the equivalent form of (59b) as…”

Section: Joint Design Of Transmit Beamforming and Mf-ris Coefficientsmentioning

confidence: 99%

Intelligent Reflecting Surface-Aided Full-Duplex Covert Communications: Information Freshness Optimization

Wang

Zheng

et al. 2023

IEEE Trans. Wireless Commun.

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Although reconfigurable intelligent surfaces (RISs) can improve the performance of wireless networks by smartly reconfiguring the radio environment, existing passive RISs face two key challenges, i.e., double-fading attenuation and dependence on grid/battery. To address these challenges, this paper proposes a new RIS architecture, called multi-functional RIS (MF-RIS). Different from conventional reflecting-only RIS, the proposed MF-RIS is capable of supporting multiple functions with one surface, including signal reflection, amplification, and energy harvesting. As such, our MF-RIS is able to overcome the double-fading attenuation by harvesting energy from incident signals. Through theoretical analysis, we derive the achievable capacity of an MF-RIS-aided communication network. Compared to the capacity achieved by the existing self-sustainable RIS, we derive the number of reflective elements required for MF-RIS to outperform self-sustainable RIS. To realize a self-sustainable communication system, we investigate the use of MF-RIS in improving the sum-rate of multi-user wireless networks. Specifically, we solve a non-convex optimization problem by jointly designing the transmit beamforming and MF-RIS coefficients. As an extension, we investigate a resource allocation problem in a practical scenario with imperfect channel state information. By approximating the semi-infinite constraints with the Sprocedure and the general sign-definiteness, we propose a robust beamforming scheme to combat the inevitable channel estimation errors. Finally, numerical results show that: 1) compared to the self-sustainable RIS, MF-RIS can strike a better balance between energy self-sustainability and throughput improvement; and 2) unlike reflecting-only RIS which can be deployed near the transmitter or receiver, MF-RIS should be deployed closer to the transmitter for higher spectrum efficiency.

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“…To overcome this limitation, the authors of [8] proposed the concept of dual-functional RIS (DF-RIS). Unlike SF-RIS, DF-RIS refers to the reconfigurable dual-functional surface that can conduct signal reflection and transmission simultaneously, such as simultaneous transmitting and reflecting RIS (STAR-RIS) [9] and intelligent omni-surface (IOS) [10].…”

Section: Introductionmentioning

confidence: 99%

“…Then, we investigate a sum rate maximization problem in an MF-RIS-aided NOMA network. Compared to the existing problems formulated in [8] and [9], the newly introduced MF-RIS constraints and highly coupled variables make the performance optimization more complicated. The main contributions of this letter are summarized as follows: 1) We propose a new concept of MF-RIS by integrating the surface electric and magnetic impedances, and power amplifier into each element so that the incident signal can be reflected, refracted, and amplified simultaneously.…”

Section: Introductionmentioning

confidence: 99%

Enhancing NOMA Networks via Reconfigurable Multi-Functional Surface

Zheng,

Ni,

Wang

et al. 2023

Preprint

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By flexibly manipulating the radio propagation environment, reconfigurable intelligent surface (RIS) is a promising technique for future wireless communications. However, the single-side coverage and double-fading attenuation faced by conventional RISs largely restrict their applications. To address this issue, we propose a novel concept of multi-functional RIS (MF-RIS), which provides reflection, transmission, and amplification simultaneously for the incident signal. With the aim of enhancing the performance of a non-orthogonal multiple-access (NOMA) downlink multiuser network, we deploy an MF-RIS to maximize the sum rate by jointly optimizing the active beamforming and MF-RIS coefficients. Then, an alternating optimization algorithm is proposed to solve the formulated non-convex problem by exploiting successive convex approximation and penalty-based method. Numerical results show that the proposed MF-RIS outperforms conventional RISs under different settings.

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Safeguarding NOMA Networks via Reconfigurable Dual-Functional Surface Under Imperfect CSI

Cited by 27 publications

References 56 publications

System throughput maximization in IRS-assisted phase cooperative NOMA networks

System throughput maximization in IRS-assisted phase cooperative NOMA networks

Intelligent Reflecting Surface-Aided Full-Duplex Covert Communications: Information Freshness Optimization

Enhancing NOMA Networks via Reconfigurable Multi-Functional Surface

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