Mission Completion Time Minimization for Secure Offloading in Aerial-IRSs Assisted MEC Systems
Authors: Gao, A., Zhang, Q., Wang, Y., Zhang, J. and Zhang, Z.
Journal: IEEE Transactions on Vehicular Technology
eISSN: 1939-9359
ISSN: 0018-9545
DOI: 10.1109/TVT.2025.3590004
Abstract:By employing unmanned aerial vehicles (UAVs) as carriers for intelligent reconfigurable surfaces (IRSs), also named as aerial-IRSs, the embedded elements of IRSs driven by the on-board energy of UAVs can not only enhance the secure offloading of legitimate ground users (GUs) by reflecting the incoming signals, but also suppress the wiretapping of malicious eavesdroppers (EUs). With this in mind, the paper focuses on minimizing the mission completion time (MCT) in aerial-IRSs assisted mobile edge computing (MEC) systems with the communication enhancement and security guarantee. Since the joint optimization of the service assignment among GUs and UAVs, aerial-IRSs' reflecting matrix, UAVs' trajectory, as well as GUs' transmitting power and computing frequency is a non-convex mixed integer non-linear programming (MINLP). To tackle the challenge of such the non-trivial problem with coupled variables, a Dichotomy- successive convex approximation (SCA) combined alternative optimization algorithm is proposed, where the minimization of MCT can be equivalently transformed into the maximization of mission completion ratio (MCR). Specifically, with any given MCR, MCT can be minimized by the Dichotomy searching. Subsequently, the maximization of MCR is further decomposed into several sub-problems that can be effectively solved by SCA method. In contrast to the current UAV assisted communication systems where the flight time is generally modeled as a fixed integration interval of optimized variables, the proposed Dichotomy-SCA algorithm minimizes UAVs' flight time just equal to the achievable MCT to fully utilize the limited on-the-flight time. Numerical simulations demonstrate that the proposed Dichotomy-SCA algorithm converges within finite iterations and achieves improved channel conditions for legitimate links while enabling secure offloading with satisfactory energy consumption.
Source: Scopus