Relay Selection for Security-Constrained Cooperative Communication in the Presence of Eavesdropper´s Overhearing and Interference

This letter addresses the problem of secure communication in a cooperative network operating in the presence of an eavesdropper as well as co-channel interference. Two opportunistic relay selection techniques are exploited for achieving physical-layer based security. The first one aims at minimizing the amount of information leaked to the eavesdropper by selecting the relay which achieves the lowest capacity to the wiretap node. In the second scheme, the relay, which yields the maximum achievable capacity at the destination node, is chosen. A performance analysis, which generalizes several previous results by accounting for interference affecting the network nodes, is conducted for both schemes and considering both selection combining and maximal ratio combining, in terms of the probability of non-zero achievable secrecy capacity and the secrecy outage probability, and numerical results are provided along with comparisons.