Abstract
Unmanned aerial vehicles (UAVs) are developing rapidly owing to flexible deployment and access services as the air base stations. In this paper, by taking the realistic assumption of imperfect channel state information at transmitter (CSIT), we investigate the robust and secure design of downlink UAV network while considering the worst-case outage constraints due to communication link uncertainties. In our proposed heterogeneous network, comprised of both UAV-cells and macro-users, rate splitting technique is deployed by UAV base-station (UAV-BS) to enhance the system performance in terms of security, power saving, and robustness against imperfect CSIT. Through our proposed design, we concurrently guarantee the fairness among all users and the robustness against imperfect CSIT while safeguarding the confidentiality. To reach this goal, we have proposed the worst-case secrecy rate (WCSR) maximization problem subjected to the worst-case outage constraint aimed at guaranteeing the quality of service (QoS) requirements of the users. To solve the resultant non-convex optimization problem we resort to the sequential parametric convex approximation (SPCA) method. Furthermore, our simulation results validates the effectiveness of the proposed scheme.