Self-Contamination for Detection of Pilot Contamination Attack in Multiple Antenna Systems

In a time-division duplex (TDD) multiple antenna system, the channel state information (CSI) can be acquired using reverse training. A pilot contamination attack occurs when during the training phase, an adversary also sends identical training (pilot) signal as that of the legitimate receiver. This contaminates the channel estimation phase and can alter the legitimate beamformer/precoder design, facilitating eavesdropping. In this letter, we propose superimposing a random sequence on the training sequence at the legitimate receiver, allowing use of source enumeration methods to detect pilot contamination attack. The proposed method is analyzed and its detection performance is illustrated via simulations.