Secure Transmission in Massive MIMO System with Specular Component-based Beamforming and Artificial Noise over Ricean Fading Channel

This paper investigates the secure transmission in a
multi-user massive MIMO system over Ricean fading channel in
the presence of a multi-antenna eavesdropper. In order to reduce
the system complexity and the channel estimation overhead,
a low-complexity beamforming (BF) scheme using only the
specular component is presented. Moreover, the generation of
artificial noise (AN) is employed at the base station (BS) for
additional security enhancement. Specifically, a tractable closedform
lower bound for the achievable ergodic secrecy rate is
derived. Furthermore, the optimal power allocation factor is
obtained based on the asymptotic analysis to maximize the
achievable ergodic secrecy rate. The analytical results reveal that
the ergodic secrecy rate improves with the increase of Ricean K-
factor and converges to a specific constant when increasing the
number of antennas. The performance of the proposed scheme
is evaluated through comprehensive simulations.