Secure Wireless Communication Using Friendly Noise Through an Untrusted Relay

In this paper, a relay based network is considered where the source can transmit confidential data with the help of non-regenerative relay node to the destination. Since the relay is assumed to be untrusted, it is very important to secure confidential data from it while maintaining the reliability of the transmission. A new approach is proposed in which a friendly noise is incorporated with the information bearing signal at the sender such that it does not degrade the integrity of the signal and the quality of the legitimate link. This friendly noise acts as jamming signal for the untrusted relay. The analytical expressions for secrecy outage probability of the proposed technique are derived. The secrecy performance of the proposed approach is compared with the traditional relay transmission and the cooperative jamming schemes. The asymptotic nature of the outage probability is also studied for the different parameters. Numerical results are also presented to verify the derived analytical expressions of the proposed approach.