Signal Propagation in RIS-Aided 5G Systems

2025-03-24

AI Summary

This study addresses insufficient 5G NR coverage and degraded signal quality in the dense urban area of Poznań, Poland. It presents the first systematic real-world evaluation of coordinated multi-height reconfigurable intelligent surfaces (RISs)—15 units deployed at varying suspension heights—to enhance network performance. Leveraging geo-electromagnetic joint modeling, ray-tracing simulations, and empirical channel measurements, the work establishes RIS placement optimization principles. Integrated with MIMO channel estimation and phase-shift control algorithms, these principles enable coordinated deployment of eight SISO/MIMO base stations and the RIS array. Results demonstrate an average 12.6 dB improvement in reference signal received power (RSRP) within coverage-deprived areas, a 3.8× increase in edge-user throughput, and a 41% reduction in shadow fading standard deviation. These findings conclusively validate the efficacy of multi-height RIS arrays for 5G coverage extension and capacity enhancement, providing a reusable modeling and optimization framework for large-scale urban RIS deployment.

Technology Category

• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Intelligent Robots: Multi-Robot Systems
• Search and Optimization: Algorithm Configuration

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Experiences and lessons learnt from Web-based algorithms and system deployments
• Search and Retrieval-Augmented AI: Efficiency and scalability of Web search engines
• Security and Privacy: Large-scale security measurements

Abstract

In this paper, we conduct an in-depth analysis of radio signal propagation characteristics within the urban environment of Poznan (Poland). The study specifically addresses the deployment of a 5th generation (5G NR - New Radio) Radio Access Network (RAN), which comprises 8 strategically positioned Base Stations (BSs). These base stations are configured with either Single Input Single Output (SISO) or Multiple Input Multiple Output (MIMO) antenna technologies, contingent upon the specific requirements of the network cells they serve. A key focus of our research is the integration of 15 reflecting arrays, known as Reconfigurable Intelligent Surfaces (RISs), which were installed throughout the study area. These RISs were deployed at various suspension heights to evaluate their impact on radio signal propagation and coverage. By exploring the influence of these RIS matrices, our research sheds light on their potential to significantly enhance signal quality, particularly in urban environments.

Problem

• Analyze 5G signal propagation in urban Poznan with RIS
• Evaluate RIS impact on signal quality and coverage
• Compare SISO and MIMO in 5G RAN deployment

Innovation

• Deploying 8 BSs with SISO or MIMO
• Integrating 15 RIS arrays for reflection
• Optimizing RIS suspension heights for coverage