Outage optimal relay selection strategy using destination-based jamming for secure communication in amplify-and-forward relay networks

In this paper, we consider a two-hop wireless system consisting of one source, one destination, one eavesdropper and multiple amplify-and-forward relays. A time-division duplex scheme is proposed that aims at minimizing the secrecy rate outage by selecting an optimal relay from the set of candidate relays. In the first time slot, the source transmits the information bearing signal, meanwhile the destination jams the eavesdropper. In the second slot, the selected relay forwards the received signals in amplify-and-forward fashion. Out of two hops, the eavesdropper can tap only the signal transmitted by the relay in the second hop. We obtain a closed-form expression of the end-to-end secrecy outage for instantaneous and statistical channel-state information of the eavesdropper. The analytical results suggest that the proposed destination-based jamming outperforms the conventional relay selection scheme without jamming. Monte Carlo simulations are performed to verify the analytical results.