Performance Comparison of Aerial RIS and STAR-RIS in 3D Wireless Environments

2025-12-09

AI Summary

To address the lack of systematic performance comparison between aerial Reconfigurable Intelligent Surfaces (RIS) and Simultaneous Transmitting and Reflecting RIS (STAR-RIS) in 3D wireless environments, this paper establishes a refined three-dimensional channel model incorporating directional radiation patterns, deployment altitude, and surface orientation. A joint beamforming and deployment optimization algorithm is proposed, integrating Weighted Minimum Mean Square Error (WMMSE) and Block Coordinate Descent (BCD). Crucially, the work reveals for the first time a complementary spatial coverage relationship: STAR-RIS significantly enhances sum rate in low-altitude scenarios owing to its full-space reflection/transmission capability, whereas conventional RIS achieves superior performance near the base station at higher altitudes due to higher reflection gain. These findings provide theoretical foundations and practical guidelines for intelligent surface selection, optimal altitude planning, and orientation design in 6G integrated space-air-ground networks.

Technology Category

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

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: Web evaluation methodologies and metrics
• Semantics and Knowledge: Methods to enhance, augment, integrate or synergize semantic models such as knowledge graphs and LLMs

Abstract

Reconfigurable intelligent surface (RIS) and simultaneously transmitting and reflecting RIS (STAR-RIS) have emerged as key enablers for enhancing wireless coverage and capacity in next-generation networks. When mounted on unmanned aerial vehicles (UAVs), they benefit from flexible deployment and improved line-of-sight conditions. Despite their promising potential, a comprehensive performance comparison between aerial RIS and STAR-RIS architectures has not been thoroughly investigated. This letter presents a detailed performance comparison between aerial RIS and STAR-RIS in three-dimensional wireless environments. Accurate channel models incorporating directional radiation patterns are established, and the influence of deployment altitude and orientation is thoroughly examined. To optimize the system sum-rate, we formulate joint optimization problems for both architectures and propose an efficient solution based on the weighted minimum mean square error and block coordinate descent algorithms. Simulation results reveal that STAR-RIS outperforms RIS in low-altitude scenarios due to its full-space coverage capability, whereas RIS delivers better performance near the base station at higher altitudes. The findings provide practical insights for the deployment of aerial intelligent surfaces in future 6G communication systems.

Problem

• Compares aerial RIS and STAR-RIS performance in 3D wireless environments
• Establishes channel models and examines altitude and orientation impacts
• Optimizes system sum-rate and provides deployment insights for 6G

Innovation

• UAV-mounted RIS and STAR-RIS for flexible deployment
• Joint optimization using WMMSE and block coordinate descent
• Full-space coverage of STAR-RIS enhances low-altitude performance