Destination assisted cooperative jamming for wireless physical layer security

A wireless network with one source, one destination, one eavesdropper and multiple decode-and-forward (DF) relays is considered. A two-slot cooperative relaying scheme is proposed that targets at maximizing the secrecy rate. In the first slot, the source transmits the information bearing signal, and at the same time, it cooperates with the destination in jamming the eavesdropper without creating interference at the relay. In the second slot, one optimally selected relay retransmits the decoded source signal, and at the same time, it cooperates with the source to jam the eavesdropper without creating interference at the destination. For the beamforming, no eavesdropper channel information is required. Optimal relay selection and also optimal power allocation among the first/second slot data signal and jamming noise are proposed. It is shown that the system secrecy rate of the proposed scheme scales with the total system power, P₀ and the number of available relays, K, according to log₂(1 + P₀/8 log K) - 1.6252bps.