Detection of Pilot Spoofing Attack Over Frequency Selective Channels

Jitendra K. Tugnait

Abstract: In a time-division duplex (TDD) multiple antenna system, the channel state information (CSI) can be estimated using reverse training. A pilot contamination (spoofing) attack occurs when during the training phase, an adversary also sends identical training (pilot) signal as that of the legitimate receiver. This contaminates channel estimation and alters the legitimate precoder/beamformimg design, facilitating eavesdropping. Past approaches to pilot spoofing detection are limited to flat fading channels. In this paper we propose a novel approach for detection of pilot spoofing attack over frequency selective channels, with unknown channels and channel lengths, except that an upperbound on the number of channel taps is assumed to be known. The proposed approach is illustrated by numerical examples and they show the efficacy of the proposed approach. A method to estimate Bob's channel regardless of the spoofing attack, is also presented and illustrated via simulations.