Manzoor Ahmed

and 8 more

This survey provides a comprehensive analysis of the integration of Reconfigurable Intelligent Surfaces (RIS) with edge computing, underscoring RIS's critical role in advancing wireless communication networks. The examination begins by demystifying edge computing, contrasting it with traditional cloud computing, and categorizing it into several types. It further delves into advanced edge computing models like Multi-Access Edge Computing (MEC), Vehicle Fog Computing (VFC), and Vehicle Edge Computing (VEC) and challenges. Progressing deeper, the survey explores RIS technology, categorizing it into passive, active, and hybrid RIS, and offers an in-depth analysis of Beyond Diagonal RIS (BD-RIS), including reflective, transmissive, and Simultaneous Transmit and Reflect (STAR) modes. Subsequently, the study assesses RIS's applications within edge computing, revealing its diverse use cases and strategies for performance analysis. The discussion comprises how RIS-driven computation can elevate rates, reduce latency, and contribute to an eco-friendly edge computing approach through better Energy Efficiency (EE). The survey also scrutinizes RIS's role in bolstering security within edge computing. To aid comprehension, each subsection is complemented by summary tables that meticulously elaborate on, compare, and evaluate the literature, focusing on aspects like system models, scenarios, RIS details, Channel State Information (CSI), offloading types, employed schemes, methodologies, and proposed solutions. This organized approach ensures a cohesive and thorough exploration of the survey’s diverse topics. By illustrating the synergy between RIS and edge computing, the study provides valuable insights or lessons learned for enhancing wireless networks, paving the way for future breakthroughs in communication technologies. Before conclusion, the survey also identifies ongoing challenges and future research directions in RIS-assisted edge computing, emphasizing the vast potential of this field.  

Wali Ullah Khan

and 5 more

With the growing demand for global connectivity and the proliferation of Internet of Things (IoT) devices, nonterrestrial networks (NTNs) have become critical in providing seamless and ubiquitous coverage and connectivity. However, integrating different NTN platforms and their integration with terrestrial networks presents significant challenges, such as managing interference and optimizing resource allocation. This work proposes a transmissive reconfigurable intelligent surface (T-RIS)-equipped low earth orbit (LEO) satellite communication in cognitive radio-enabled integrated NTNs. In the proposed system, a geostationary (GEO) satellite operates as a primary network, and a T-RIS-equipped LEO satellite operates as a secondary wireless network. The objective is to maximize the sum rate of T-RIS-equipped LEO satellite communication using downlink non-orthogonal multiple access (NOMA) while ensuring the service quality of GEO cellular users. Our framework simultaneously optimizes the total transmit power of LEO, NOMA power allocation for LEO user equipment (LUE), and T-RIS phase shift design, subject to the service quality of LUE and interference temperature to the primary GEO network. To solve the non-convex sum rate maximization problem, we first adopt successive convex approximations to reduce the complexity of the formulated optimization. Then, we divide the problem into two parts, i.e., power allocation of LEO and phase shift design of T-RIS. The power allocation problem is solved using Karushâ Ȃ ŞKuhnâ Ȃ ŞTucker conditions, while the phase shift problem is handled by Taylor approximation and semidefinite programming. Numerical results are provided to validate the proposed optimization framework.

Manzoor Ahmed

and 8 more

Abdul Wahid

and 7 more

The recent development of metasurfaces, which may enable several use cases by modifying the propagation environment, is anticipated to have a substantial effect on the performance of 6G wireless communications. Metasurface elements can produce essentially passive sub-wavelength scattering to enable a smart radio environment. STAR-RIS, which refers to reconfigurable intelligent surfaces (RIS) that can transmit and reflect concurrently (STAR), is gaining popularity. In contrast to the widely studied RIS, which can only reflect the wireless signal and serve users on the same side as the transmitter, the STAR-RIS can both reflect and refract (transmit), enabling 360-degree wireless coverage, thus serving users on both sides of the transmitter. This paper presents a comprehensive review of the STAR-RIS, with a focus on the most recent schemes for diverse use cases in 6G networks, resource allocation, and performance evaluation. We begin by laying the foundation for RIS (passive, active, STAR-RIS), and then discuss the STAR-RIS protocols, advantages, and applications. In addition, we categorize the approaches within the domain of use scenarios, which includes increasing coverage, enhancing physical layer security (PLS), maximizing sum rate, improving energy efficiency (EE), and reducing interference. Next, we will discuss the various strategies for resource allocation and measures for performance evaluation. We aimed to elaborate, compare, and evaluate the literature in terms of setup, channel characteristics, methodology, and objectives. In conclusion, we examine the open research problems and potential future prospects in this field.