Physical Layer Security of TAS/MRC Over $\kappa$-$\mu$ Shadowed Fading Channel

This paper investigates the impact on the achievable secrecy performance of multiple-input multiple-output systems by dealing with realistic propagation conditions. Specifically, we focus on the $\kappa$-$\mu$ shadowing fading model, which has proven to be more accurate in characterizing mm-wave scenarios than traditional Rice and Rayleigh ones. By considering transmit antenna selection and maximal ratio combining at the receiver ends, we study two different scenarios, namely: (i) the transmitter has knowledge of the channel state information (CSI) of the eavesdropper link, and (ii) the transmitter does not know eavesdropper's CSI. Based on these assumptions, we derive novel analytical expressions for the secrecy outage probability (SOP) and the average secrecy capacity (ASC) to assess the secrecy performance in passive and active eavesdropping scenarios, respectively. Moreover, we develop analytical asymptotic expressions of the SOP and ASC at high signal-to-noise ratio regime. Some useful insights on how to obtain noticeable improvements in the secrecy performance are also provided.