Secure air-to-ground transmission with jamming links blocked by the eavesdropper

Abstract

Secure air-to-ground communication when an eavesdropper is able to block the jamming link from a jammer is considered in this paper. A feedback-aided cooperative jamming scheme is proposed, where the transmitter, the destination, and the jammer alternately design and send artificial noise to protect the private information in three stages. It shows that even if the jamming links are blocked, the eavesdropper will inevitably be impacted by artificial noise. We limit the eavesdropping rate to a constant, and guarantee the minimum secrecy rate scales with the transmit power. We allocate power between the artificial noise and the private information, and obtain the optimal ratio to maximize the minimum secrecy rate. We analyze the symbol error probability of the destination and the eavesdropper when the transmitter exploits M-ary constellation modulation. It shows that a high symbol error floor is created at the eavesdropper but the symbol error probability at the legitimate destination decreases with the transmit power.