Improving physical layer security in full-duplex relaying system

Secure transmission is possible in wireless communication due to physical layer security with the help of relay in the presence of eavesdroppers. In this system, we investigate the secrecy performance for desired users where undesired users, who are not selected for data reception, may overhear the message signal as eavesdroppers. Here, relay operate with decode-and-forward (DF) mode with full-duplex jamming (FDJ) under total transmit power constraint. First obtain the secrecy rate for half-duplex transmission (HDT), which requires two time slot for data reception and transmission. Second obtain the secrecy rate in FDJ. In this system, we use FDJ scheme to overcome the overhearing of eavesdroppers, in which a desired receiver send a jamming signal towards untrustworthy relay when relay receive a message signal from transmitter and then relay decode and forward the received signal towards desired receiver on the same time slot. Now receiver receives the message signal with jamming and only this desire receiver can subtract the jamming signal and also it will create an interference to prevent the overhearing of undesired receiver. The result indicate that secrecy rate of FDJ is better than the HDT.