Energy-Efficient Aerial RIS-Assisted D2D Communications for Sustainable Disaster-Resilient Wireless Networks

Abstract

In disaster-stricken regions, terrestrial communication infrastructure is often severely damaged or unavailable, making the rapid restoration of reliable connectivity a critical challenge. Device-to-device (D2D) communication has emerged as a promising solution for enabling direct communication among nearby users without relying on fixed infrastructure. However, its performance is often constrained by severe path loss, limited coverage, and unreliable links in obstructed environments. To address these limitations, this paper proposes an Aerial reconfigurable intelligent surface (ARIS)-assisted D2D communication framework that enhances network resilience, coverage, and energy efficiency in post-disaster scenarios. In the proposed system, uncrewed aerial platforms equipped with RISs dynamically adjust reflection coefficients to establish favorable propagation conditions and improve the reliability of D2D links. Closed-form analytical expressions are derived for key performance metrics, including outage probability, coverage probability, and average symbol error rate, under practical fading conditions. Additionally, an asymptotic analysis is conducted to reveal the impact of system parameters on network performance. To further improve system sustainability, an energy-efficiency maximization problem is formulated by jointly optimizing UAV placement, ARIS phase shifts, and transmit power. Simulation results validate the accuracy of the analytical derivations and demonstrate that the proposed ARIS-assisted D2D framework significantly enhances the performance in terms of communication reliability and energy efficiency, making it a promising green communication solution for resilient disaster-response networks. Furthermore, simulation results show up to 12.5 dBm transmit power reduction when deploying 5 UAVs compared to a single-UAV baseline, alongside significant energy efficiency gains.