volume | PIER Journals

Abstract

Reconfigurable Intelligent Surfaces (RIS) have become a trend recently and represent a revolutionary development in wireless communications. Although RIS is utilized to enhance spectrum efficiency, particularly in Multi-User Multi Input Multi Output (MU-MIMO) environments, the conventional diagonal RIS(D-RIS) architecture represents a significant limitation. Beyond-diagonal RIS designs, such as fully-connected (FC-BD-RIS) and group-connected (GC-BD-RIS), are effective in controlling scattering and performance due to their use of reflective RIS elements. This research analyzes in detail the simulation of FC-BD-RIS, GC-BD-RIS, D-RIS and baseline NO-RIS architectures assuming a real communication environment. The results show that the FC-BD-RIS architecture achieves the best performance and highest rate under all operational conditions, while the GC-BD-RIS architecture showed balanced and efficient performance relative to the computational complexity compared to the FC-BD-RIS. Ultimately, the behavior of per-user rate has demonstrated the ability of beyond-diagonal BD-RIS architectures to suppress interference and achieve fairness within MU-MIMO scenarios. Based on the results of this work, GC-BD-RIS is the most practical and suitable for future large-scale 6G applications. This work draws attention to the trade-off among design, optimization, and achievement of RIS-enabled MU-MIMO systems.

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Ms. Huda A. Al-Tayyar

Dr. Omar M. Ali

Dr. Reyam H. Ali

Dr. Ali H. Saeed