LAUSR

In the channel training phase, the attacker launches a pilot contamination attack by sending a synchronized and identical pilot signal with the legitimate transmitter. Such an attack can contaminate the channel estimation and alter the legitimate beamformer design. In this letter, first, we propose a pilot contamination attack detection scheme for wireless communications. By considering the prior uncertainty of the attack, we find that the decision-maker will conservatively decide the state of the attack, which is a subjective choice. In this case, we derive the subjective detection probability, the subjective false alarm probability, and the threshold. We analyze the tradeoff problem between ergodic wiretap channel rate and subjective detection probability. Next, based on the worst case that the attacker adopts the optimal power allocation to launch the optimal attack, we discuss the defense strategy of the optimal attack. Simulations show that the proposed scheme has a better performance than the benchmark method.