Table 1. Comparative analysis of previous studies on RIS and UAV-assisted communications.

Reference	Key focus	Methodology/Approach	Findings/Contributions
Mohsan et al. (2022)	Overview of trends in RIS-based massive networks	Survey and trend analysis	Identifies key challenges and potential solutions for deploying massive RIS-assisted networks.
Bansal et al. (2023)	Optimization of RIS selection in UAV-based multiuser networks	Deep reinforcement learning for RIS selection optimization	Improves downlink communication performance in multi-RIS networks with outdated CSI.
Bithas et al. (2024)	Joint optimization of control and data acquisition in UAV networks	Deep reinforcement learning approach	Enhances data acquisition efficiency and control in UAV-assisted sensor networks.
Wu et al. (2024)	Secure communication in RIS-aided UAV networks	Deep reinforcement learning for secure resource allocation	Provides a model for enhancing security in RIS-aided UAV communications using deep learning.
Cang et al. (2023)	Energy efficiency in RIS-assisted UAV networks	Genetic algorithm for optimizing energy consumption	Proposes an energy-efficient communication strategy for UAV networks.
You et al. (2023)	Optimization of RIS-based UAV NOMA networks	Deep reinforcement learning with UAV and NOMA integration	Proposes a model to enhance downlink efficiency using UAVs in NOMA networks.
Iqbal et al. (2023)	Resource allocation in RIS-assisted multi-UAV networks	Deep reinforcement learning for resource optimization	Demonstrates improved resource allocation and energy efficiency in multi-UAV networks.
Javad-Kalbasi, Al-Abiad & Valaee (2023)	Integration of IoT with RIS-assisted UAV communications	Deep reinforcement learning	Shows improvement in IoT connectivity and power efficiency using RIS-assisted UAV systems.
Lahmeri, Kishk & Alouini (2021)	Survey on reinforcement learning applications in RIS	Literature review	Highlights the benefits and limitations of reinforcement learning approaches in RIS.
Nguyen et al. (2021)	Challenges and trends in RIS-assisted UAV communication	Analysis of current research and future directions	Identifies key research gaps and suggests directions for future work in RIS-UAV communication.