Attacker Detection in Massive MIMO Systems Over Spatially Uncorrelated Rician Fading Channels

Abstract

Physical security is a potentially promising research direction for the fifth-generation and beyond networks. This paper investigates the physical layer security of massive multiple-input multiple-output (MIMO) spatially-uncorrelated Rician fading channels in time-division duplex mode. Relying on the fact that the propagation channels need to be estimated in practice to detect the desired signals in the uplink and construct the precoding vectors in the downlink, an active attack on the pilot training phase is potentially harmful to the wireless networks.We demonstrate how a jammer can attack in the training phase of Massive MIMO with spatially-uncorrelated Rician fading channels and show the scheme for detecting the presence of a jammer. Based on the fundamental properties of Massive MIMO communication, the network can treat the jamming effects as additive white Gaussian noise. A threshold to detect the existence of the active jammer is, therefore, computed in closed-form expression with a sufficiently large number of antennas at the base station. The key merit of our proposed method is that it only requires partial channel information and two training time slots to detect the jammer activity. Numerical results manifest the effectiveness of our proposed active jamming detection over various system parameter settings. Furthermore, the benefits of the dominant line-of-sight (LoS) components have been testified. In particular, the detection probability is improved by about 1.5 times with the presence of the LoS components, while the false-alarm probability gets improved by more than ten folds.