Physical layer security enhancement with generalized selection diversity combining

In this paper, we present and analyze utilizing generalized selection combining (GSC) scheme to enhance the physical layer (PHY) security of a wireless communication system consisting of a single antenna transmitter, a multi-antennas receiver and a multi-antennas eavesdropper. We consider a practical scenario where GSC scheme is applied to the receiver considering both the complexity and the energy dissipation while maximal ratio combining (MRC) scheme is applied to the eavesdropper in order to maximize its instantaneous signal to noise ratio (SNR). This work bridges the gap between the existing works utilizing MRC scheme and transmit antenna selection (TAS) scheme to enhance the PHY security. Closed-form expressions for both the probability of non-zero secrecy capacity and the exact secrecy outage probability are derived over Rayleigh fading channels. The security capacity performances are also shown and analyzed through numerical results. The impacts of the number of selected branches, the average SNR of transmitter´s channel and eavesdropper´s channel are discussed.