Physical-Layer Secure Precoding for UAV Communications with Full-Duplex Jamming

Although unmanned aerial vehicles (UAVs) are enabling various applications in military, public, and commercial fields, the issue of information security in UAV communications is a critical issue which hinder the extensive applications of the UAVs. To cope with this issue, physical layer security is an alternative security technology, which can enhance the information security by flexibly adjusting transmission strategies and parameters to accommodate the channel changes. In this paper, the information security of the UAV communications is investigated from the perspective of physical layer security. The ground-to-air communications are considered under the presence of eavesdroppers, while the UAV can operate in a full-duplex mode so that it can perform cooperative jamming to confuse the eavesdroppers. The achievable secrecy rate of the UAV networks is maximized by the joint designs of the transmit precoding and cooperative jamming. To this end, an intractable optimization problem is formulated, and a solution scheme is proposed by using the approaches of equivalent transformation and alternating optimization. Simulation results demonstrate that the proposed scheme achieves a notable improvement in secrecy rate.