In light of the revolutionary requirements of the sixth generation (6G) and beyond wireless networks, reconfigurable intelligent surface (RIS) and rate-splitting multiple access (RSMA) have emerged as pivotal technologies due to their potential for improving spectral efficiency, user fairness, and interference management. This survey explores the theoretical foundations, architectural frameworks, and design strategies of RIS-assisted RSMA, emphasizing the combined adaptability of RIS’s wireless propagation control and RSMA’s multi-user flexibility for dynamic spectrum management. The article first discusses the fundamental concepts of RSMA and RIS technologies. Then, we investigate various enabling technologies for RIS-RSMA networks, highlighting key advancements in interference mitigation, energy efficiency, and security for future networks. Subsequently, some optimization techniques crucial for enhancing RIS-RSMA network performance are presented. Additionally, we examine advanced machine learning (ML) approaches that enable RIS configurations to dynamically adapt to changing network requirements. Techniques such as deep reinforcement learning support real-time adjustments, creating more scalable and resilient RIS-RSMA architectures. Finally, we discuss open research directions for advancing RIS-assisted RSMA in emerging 6G applications. We also consider the potential of advanced ML techniques, including quantum-based ML and large language models, to handle the complexities of large-scale network optimization. This comprehensive survey addresses critical challenges and current advancements. It offers a roadmap for future research in RIS-assisted RSMA networks, paving the way for robust, intelligent, and adaptive 6G wireless communication systems.

Space-air-ground integrated networks (SAGINs) are revolutionizing wireless communications by integrating space, aerial, and terrestrial networks, providing global connectivity, aiding underserved regions, and enabling 6G applications. This paper proposes a dual reconfigurable intelligent surfaces (RISs)-assisted cooperative hybrid free space optical (FSO)/ radio frequency (RF) communication framework for SAGINs to address the reliable communications challenges. The framework integrates an optical RIS on a low Earth orbit satellite and an RF aerial RIS, enhancing FSO link performance and mitigating RF line-of-sight blockages. The system uses selection combining to dynamically choose the stronger signal between FSO and RF links, ensuring robust communication in varying conditions. We derive analytical expressions for key performance metrics such as outage probability, average symbol error rate, and ergodic capacity, considering pointing errors and atmospheric turbulence effects on the FSO link. Simulation results verify the analytical derivations, highlighting the critical role of RISs in enhancing the system performance.

As terrestrial networks face limitations in delivering global wireless communications, the shift towards non-terrestrial networks, particularly satellite-based systems, becomes increasingly essential for connecting remote regions. However, these networks are susceptible to security risks, such as eavesdropping, making the assurance of physical layer security (PLS) critical to achieving secure global wireless connectivity. Emerging technologies like reconfigurable intelligent surfaces (RISs) and higher frequency bands, such as the THz range, offer promising solutions for enhancing the PLS. This paper investigates the secrecy performance of a RIS-assisted satellite communication system operating in the THz band. We derive expressions for key security metrics, including the secrecy outage probability (SOP), lower bound SOP, and intercept probability (IP). Furthermore, in a practical scenario, we analyze the effect of misalignment and solar scintillation on reliable satellite communication. Simulation results validate the analytical findings, highlighting the importance of utilizing RIS in improving secrecy performance.

The Age of Information (AoI) is a critical metric in next-generation communication networks, quantifying data freshness essential for latency-sensitive applications in 6G systems, such as autonomous driving and industrial IoT. This paper presents an AoI analysis within a downlink full-duplex (FD) cooperative simultaneous wireless information and power transfer (SWIPT) system, employing rate-splitting multiple access (RSMA) for short packet communication to enhance timely data updates. By integrating RSMA with SWIPT and FD capabilities, we propose a robust framework to reduce the AoI. In this regard, closed-form expressions of the average block error rate of the RSMA-enabled FD cooperative SWIPT system are derived and validated via Monte Carlo simulations. The results demonstrate that RSMA outperforms non-orthogonal multiple access (NOMA) and FD cooperative SWIPT NOMA in terms of error performance, while also reducing the inherent system design complexity. Our findings reveal that RSMA is a promising approach for minimizing AoI across various system configurations, offering valuable insights for designing future 6G networks that prioritize low latency, high reliability, and data freshness.

Integrating aerial reconfigurable intelligent surfaces (ARIS) with unmanned aerial vehicles (UAVs) presents a significant opportunity to enhance the performance of wireless networks. This integration allows ARIS to be mounted on UAVs, providing greater configuration flexibility, establishing reliable air-ground connections, and enabling three-dimensional signal reflections. However, this integration also introduces unique challenges related to physical layer security (PLS). Addressing these security considerations is essential, given the significance of secure and reliable communication. In this paper, we investigate the PLS for ARIS to assist wireless communication systems. Our objective is to select the ARIS that maximizes the secrecy capacity of the proposed system model. Two selection approaches are considered, namely, optimal and sub-optimal ARIS selection, and analytical expressions for the secrecy outage probability and probability of non-zero secrecy capacity over Nakagami-m fading channels are derived. Additionally, we examine the impact of varying the number of UAVs and the locations of the eavesdropper in practical scenarios. Moreover, the collaborative scenario is investigated, where all UAVs cooperate to improve secrecy transmission. Each ARIS reflects identical copies of the transmitted signal on the same time-frequency channel without mutual interference. The optimization problem of UAV locations and RIS phase shifts to maximize the secrecy capacity under specific constraints is formulated and addressed using an improved particle swarm optimization technique. These scenarios highlight the potential of ARIS in achieving secure and efficient wireless communications. Simulation results verify the analytical derivations, highlighting the critical role of selecting the ARIS in enhancing secrecy performance. As revealed by simulations, doubling the number of UAVs leads to a notable improvement in the average secrecy rate by approximately 77.78%. The obtained results highlight the significance of the proposed ARIS-assisted system in enhancing the PLS for wireless communications.

Integrating aerial reconfigurable intelligent surfaces (ARIS) with unmanned aerial vehicles (UAVs) presents a significant opportunity to enhance the performance of wireless networks. This integration allows ARIS to be mounted on UAVs, providing greater configuration flexibility, establishing reliable air-ground connections, and enabling three-dimensional signal reflections. However, this integration also introduces unique challenges related to physical layer security (PLS). Addressing these security considerations is essential, given the significance of secure and reliable communication. In this paper, we investigate the PLS of UAV-enabled ARIS-assisted wireless communication systems. Our objective is to maximize the secrecy capacity of the proposed system model. We derive analytical expressions for the secrecy outage probability and probability of non-zero secrecy capacity over Nakagami-m fading channels. Additionally, we examine the impact of varying the number of UAVs in practical scenarios. Simulation results verify the analytical derivations, highlighting the critical role of selecting the optimal UAV in enhancing secrecy performance.

This paper investigates the physical layer security of inband underlay Device-to-Device (D2D) communication, where there is no direct link between D2D users. In this respect, optimal relay selection is utilized to secure the D2D transmission. The eavesdropper uses either maximal-ratio combining or selection combining to improve the wiretapped signals. The D2D secrecy performance analysis is performed regarding the secrecy out-age probability (SOP) and the probability of non-zero secrecy capacity, and closed-form expressions are provided. To validate the correctness of our analysis, numerical and simulation results are presented. Furthermore, the asymptotic analysis of the SOP is provided, where new insights into the system parameters are revealed.

This paper investigates physical layer security and data transmission in cellular networks with inband underlay Device-to-Device (D2D) communication, where there is no direct links between D2D users. We propose the use of full-duplex (FD) transmission and dual antenna selection at the relay node. Thanks to the FD transmission, the relay node can simultaneously act as a jammer to enhance the cellular network secrecy performance, while improving the D2D communication data transmission. This describes a practical attractive scheme, where spectrum sharing is beneficial for both the D2D and cellular networks in terms of throughput enhancement and security provisioning, respectively. We analyze the secrecy performance of the cellular network and derive closed-form expressions for the secrecy outage probability (SOP) and the probability of non-zero secrecy capacity. We also derive a closed-form expression of the D2D outage probability. Furthermore, asymptotic analysis for SOP is performed. Simulation and numerical results are provided to verify the efficiency of the proposed scheme and to validate the accuracy of the derived expressions.

This paper studies the physical layer security (PLS) of underlay multihop device-to-device (D2D) relaying. New closed-form expressions on the lower bound of the outage probability, the secrecy outage probability (SOP), and the probability of non-zero secrecy capacity are derived. Hence, new insights into the secrecy performance of the underlay multihop D2D relaying are revealed. The obtained analysis is validated through Mont-Carlo simulations.