  In this paper, we study the problem of physical layer security in the uplink
of millimeter-wave massive multiple-input multiple-output (MIMO) networks and
propose a jamming detection and suppression method. The proposed method is
based on directional information of the received signals at the base station
antenna array. The proposed jamming detection method can accurately detect both
the existence and direction of the jammer using the received pilot signals in
the training phase. The obtained information is then exploited to develop a
channel estimator that excludes the jammer's angular subspace from received
training signals. The estimated channel information is then used for designing
a combiner at the base station that is able to effectively cancel out the
deliberate interference of the jammer. By numerical simulations, we evaluate
the performance of the proposed jamming detection method in terms of correct
detection probability and false alarm probability and show its effectiveness
when the jammer's power is substantially lower than the user's power. Also, our
results show that the proposed jamming suppression method can achieve a very
close spectral efficiency as the case of no jamming in the network
