Achieving Secrecy Energy Efficiency Fairness in UAV-Enabled Multi-User Communication Systems

This letter investigates the secrecy energy efficiency (SEE) fairness of unmanned aerial vehicle (UAV)-enabled multi-user communication systems where a UAV disseminates data to multiple ground users (GUs) in the presence of an eavesdropper (EVE). Taking into account the security threats from EVE, the limited on-board energy of UAV and the fairness among GUs, we formulate a user-oriented SEE maximization problem to maximize the minimum GU’s SEE by jointly optimizing the UAV trajectory and resource allocation subject to the UAV motion constraints and resource budgets. Due to the difficulty in solving this problem that arises from the fractional structure of SEE and the coupling characteristic of optimization variables, we first exploit the successive convex approximation to transform the original problem to a convex one, which is further converted into a second order cone program to reduce the computational complexity. Then, a convergent iterative algorithm is designed to find the suboptimal solution. Simulation results show that the proposed scheme significantly improves SEE fairness of GUs as compared to some benchmark schemes.