Securing Aerial Offloading via Intelligent Omni-Surface

Abstract

Different from conventional reflecting-only metasurfaces, intelligent omni-surfaces (IOSs) are capable of reflecting and transmitting the received signals simultaneously. As such, users located at both sides of IOSs can be served efficiently. In this paper, a novel IOS-enhanced aerial offloading system is proposed in the presence of one ground eavesdropper. To maximize the secrecy energy efficiency (SEE) of the considered system, a non-convex problem is formulated by determining offloading strategy, allocating transmit power, designing reflection coefficients, and deploying unmanned aerial vehicle (UAV) location. To solve this non-convex and non-linear problem, an alternating optimization algorithm is developed to obtain a suboptimal solution with low complexity. Finally, simulation results demonstrate that: i) the SEE performance of aerial offloading systems can be significantly improved by the IOS as compared to benchmark schemes; ii) compared with intelligent reflecting surfaces (IRSs), IOSs can considerably extend the security deployment space of UAV.