  Physical layer security (PLS) techniques can help to protect wireless
networks from eavesdropper attacks. In this paper, we consider the
authentication technique that uses fingerprint embedding to defend 5G cellular
networks with unmanned aerial vehicle (UAV) systems from eavesdroppers and
intruders. Since the millimeter wave (mmWave) cellular networks use narrow and
directional beams, PLS can take further advantage of the 3D spatial dimension
for improving the authentication of UAV users. Considering a multi-user mmWave
cellular network, we propose a power allocation technique that jointly takes
into account splitting of the transmit power between the precoder and the
authentication tag, which manages both the secrecy as well as the achievable
rate. Our results show that we can obtain optimal achievable rate with expected
secrecy.
