Improving physical layer security jointly using full-duplex jamming receiver and multi-antenna jammer in wireless networks

The issues of the physical layer security are studied, where one transmitter (Alice), one full-duplex (FD) legitimate receiver (Bob) and one multi-antenna jammer (Charlie) are considered to defend against multiple passive and non-colluding eavesdroppers (Eves), for multiple-input multiple-output wiretap channels. With the assumption that the complete channel state information (CSI) for main channels and the statistical CSI for Eves' channels are available, an improved secrecy transmission design is proposed to minimise the secrecy outage probability (SOP), under the minimum secrecy rate requirement. In addition to integrating artificial noise aided transmit beamforming and multi-antenna cooperative jammer to impair Eves' channels, which is widely used in many existing works, a FD legitimate receiver is applied together to further enhance physical layer security. Based on the basic probability theory and convex optimisation, the accurate closed-form expression of the SOP is derived, and the impacts on secrecy performance are described, including the qualities of main channels, the Alice's transmit power and the number of Eves. Numerical results show that the proposed scheme using the FD Bob can significantly enhance the system security, as compared with that employing the half-duplex Bob.