Eavesdropping via pilot relay attack

In this paper, we propose a new type of attack from the perspective of the eavesdropper. The full-duplex eavesdropper acts as a relay in the uplink channel estimation phase forwarding the received pilot signal from legitimate receiver to confound the legitimate transmitter. Compared to pilot spoofing attack, which needs the eavesdropper to know the pilot signal accurately, the pilot relay attack only needs the eavesdropper to know the frame structure of the legitimate transceiver pair. In this paper, we study the optimal amplify-and-forward strategy of the eavesdropper so that its eavesdropping behavior is harder to be detected by maximizing the transmission rate from the legitimate transmitter to the legitimate receiver under the constraint that the eavesdropping rate is larger than the legitimate transmission rate. Furthermore, we analyze the performance of the pilot relay attack when Eve is at different locations, the simulations have shown that different strategies should be adopted at different locations.