Integration of Reconfigurable Intelligent Surfaces (RISs) in D-MIMO Networks for 6G
Typ
Examensarbete för masterexamen
Master's Thesis
Master's Thesis
Program
Communication Engineering (MPCOM), MSc
Publicerad
2024
Författare
Vayal Parambath, Akshay
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
Abstract
The distributed MIMO (D-MIMO) systems are one of the potential technique to densify the ever-evolving 5G networks and beyond (6G) technologies. However, the scalability of D-MIMO systems to large-scale networks in a practical scenario is very challenging. The aim towards sustainability and other economic challenges in the upcoming 6G networks resulted in the exploitation of cost-effective and energyefficient dynamic access point (AP) clustering techniques and use of densification enablers for providing high performance and reliability for its users. Reconfigurable intelligent surface (RIS) is a technology that is well known for its low-cost, rapid deployability, and energy-efficient properties, which can add extra diversity to the spatial domain if deployed in a network. This work explores the benefits gained by integrating RIS into a D-MIMO system in terms of major KPIs of focus, i.e., energy efficiency and service coverage of the system. In this study, we focus an indoor use case with a high UE density where the service coverage is very scarce due to high obstacle density that results in huge pathloss and shadowing. Towards the end, we propose dynamic user-centric AP clustering and RIS placement techniques adapted for addressing such high UE demands in an indoor D-MIMO system. Here, for configuring RIS phase-shifts we use an alternating optimization method which is a sub-optimal solution to lower the computational complexity. Finally, we compare an RIS-assisted D-MIMO system with a conventional D-MIMO system to prove that the integration of RISs in D-MIMO system is a potential approach to enhance the service coverage and energy efficiency, while satisfying the scalability requirement in 5G and beyond (6G) technologies.
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Keywords: D-MIMO, RIS, User-centric AP clustering, Energy efficiency, Service coverage probability, 5G, 6G, Distributed MIMO.