Performance Analysis of Cooperative Aerial RIS for Millimeter-Wave SISO Systems

Abstract

In this paper, we propose a physics-aware pathloss model for cooperative aerial reconfigurable intelligent surfaces (Co-ARIS) in millimeter-wave (mmWave) communications. The proposed model incorporates antenna radiation patterns, element-level scattering characteristics, line-of-sight (LoS) and non-line-of-sight (NLoS) link states, and NLoS phase uncertainty without assuming channel state information (CSI). A single-input single-output (SISO) configuration is adopted to isolate intrinsic propagation characteristics from multi-antenna spatial gains. Simulation results show that idealized RIS models can overestimate the received power when antenna directivity and NLoS phase uncertainty are neglected. The receivedpower degradation with respect to inter-ARIS coherence is also evaluated, indicating that synchronization loss reduces the additional cooperative gain among multiple ARISs.