The Impact of Using Intelligent Reflecting Surfaces (IRSs) on Minimizing Operational Costs in UAV Wireless Networks

Integrating Non-Orthogonal Multiple Access (NOMA) and Intelligent Reflecting Surfaces (IRSs) with Unmanned Aerial Vehicles (UAVs) presents a promising research area with significant potential to enhance the efficiency and performance of wireless communication systems. This work proposed a novel communication approach that leverages user-pairing-based NOMA to provide high data-rate wireless coverage for Internet of Things (IoT) devices using UAV-IRS systems. By combining the benefits of NOMA and IRS, we can achieve higher spectral utilization, superior energy efficiency, and a more reliable communication system. However, providing wireless coverage to IoT devices using a single UAV-IRS system can be challenging due to a UAV’s low transmit power. As a result, the optimization problem is formulated to minimize the number of required UAV-IRS systems while ensuring that each IoT device meets its Quality-of-Service (QoS) requirements. Specifically, we propose an efficient heuristic algorithm to determine the minimum number of UAV-IRS systems required to serve IoT devices. Our proposed approach reduces operational costs during the planning and operation of wireless network systems using UAV-IRS, while extending the wireless coverage for IoT devices. The proposed approach is evaluated through simulations, and the results show that integrating NOMA and IRS with UAVs improves the performance and efficiency of wireless communication systems. Additionally, the proposed approach reduces the number of required UAV-IRS systems. The proposed IRS-NOMA system uses only seven UAVs, whereas the NOMA system without IRS requires nine UAVs to ensure 100% user coverage at the same data rate.