Physical Layer Security with Maximal Ratio Combining over Heterogeneous \(\kappa {-}\mu \) and \(\eta {-}\mu \) Fading Channels

This paper investigates physical layer security of maximal ratio combining (MRC) in a heterogeneous fading environment, where the legitimate channel and the wiretap channel are modeled as \(\kappa {-}\mu \) and \(\eta {-}\mu \) fading distributions, respectively. The legitimate receiver adopts MRC to maximize the probability of secure transmission, whereas the eavesdropper adopts MRC to maximize the probability of successful eavesdropping. If the eavesdropper’s channel state information (CSI) is available at the transmitter, the exact and asymptotic expressions of the average secrecy capacity are derived as the security performance metrics. While, if the eavesdropper’s CSI is not available at the transmitter, the exact and asymptotic expressions of the secrecy outage probability are derived as the security performance metrics. In both of the two cases, the impact of the number of antennas as well as the channel fading parameters on the the secrecy performance is further analyzed. Finally, the simulation results are given to verify the validity of the theoretical analysis.