Security Enhancement for UAV-Assisted ISCC Networks: Considering the Coupling Between Uplink and Relaying Transmissions

Abstract

Integrated sensing, communications, and computing (ISCC) has emerged as a key paradigm for next-generation wireless networks. To unlock high spectral efficiency and flexible on-demand coverage of ISCC, non-orthogonal multiple access (NOMA) and uncrewed aerial vehicles (UAVs) are considered promising enabling technologies. However, due to spectrum sharing and line-of-sight (LoS)-dominated channels, secure offloading faces unique security challenges that stem from the strong coupling between uplink and relaying transmissions. In this paper, we investigate a secure ISCC network supported by a NOMA-UAV platform, where a full-duplex UAV acts as an aerial relay to assist secure uplink offloading while simultaneously detecting both passive and active eavesdroppers that threaten the uplink and relaying transmissions, respectively. With the goal of maximizing the weighted sum secrecy rate, we jointly optimize the transmit power of communication users, the NOMA decoding orders, and the UAV’s transmit beamforming, trajectory, and velocity. The formulated non-convex problem is solved via an iterative alternating optimization algorithm that incorporates closed-form update, successive convex approximation, and semidefinite relaxation. Numerical results validate the effectiveness of the proposed secure ISCC optimization framework and highlight the important roles of NOMA and UAV trajectory design in enhancing the secrecy performance.