Latency Minimization for C-NOMA Based Multi-UAV MEC Systems

The clustered non-orthogonal multiple access (C-NOMA) allows multiple users to share link resources for improving spectrum efficiency. It can be applied to unmanned aerial vehicle (UAV) and mobile edge computing (MEC) networks to provide offloading computing services for massive access users. However, due to the line-of-sight nature of UAV communication, wireless information can be easily eavesdropped by the malicious users. In this paper, we propose a secure communication scheme for C-NOMA based multi-UAV MEC system towards an aerial eavesdropper, which aims to minimize the system latency while satisfying the security and computing resource constraints. Firstly, we decompose the original problem into three sub-problems. Then, the successive convex approximation and the block coordinate descent methods are used to convert these sub-problems into convex forms with respect to offloading ratio, computing resource allocation and transmit power, respectively. Finally, these sub-problems are alternately solved in an iterative manner. Simulation results show that the proposed scheme can effectively reduce the system latency for all users compared to the baseline schemes.