Secure UAV-enabled OFDMA Communications

In this paper, an unmanned aerial vehicle (UAV) enabled secure downlink communication is considered, where a single-antenna UAV serves multiple ground users facilitated by orthogonal frequency-division multiple access (OFDMA), in the presence of an eavesdropper (EV) with imperfect channel state information. To enhance the secrecy rate (SR), we employ a power splitting approach, where part of the transmit power is used for communication while the rest is used for jamming. We maximize the average secrecy rate (ASR) by jointly optimizing the bandwidth, trajectory, power allocation, and power splitting ratio. To tackle this non-convex and computationally intractable optimization problem, we propose a novel algorithm by employing successive convex approximation, block coordinate descend and S-procedure. Numerical results show that our proposed joint optimization algorithm outperforms the benchmark schemes.