Joint Relay and Jammer Selection for Wireless Physical-Layer Security

This chapter investigates the physical-layer security for a cooperative wireless network, where a source node transmits to its destination with the aid of multiple intermediate nodes in the face of an eavesdropper. We propose a joint relay and jammer selection scheme for protecting the source-destination transmission against the eavesdropper. To be specific, among the multiple intermediate nodes, one node is first selected to act as the relay for assisting the transmission from the source to destination and meanwhile, another node is chosen as the jammer that is employed to transmit an artificial noise for interfering with the eavesdropper. Also, we consider the conventional pure relay selection and pure jammer selection as benchmark schemes. In the pure relay selection scheme, an intermediate node is selected as the relay to assist the source-destination transmission. By contrast, the pure jammer selection allows an intermediate node to act the jammer for confusing the eavesdropper. We derive the closed-form intercept probability expressions for the proposed joint relay and jammer selection as well as the conventional pure relay selection and pure jammer selection schemes. Numerical results demonstrate that the joint relay and jammer selection outperforms the pure relay selection and pure jammer selection methods in terms of the intercept probability, showing the security benefit of employing the proposed scheme to protect the wireless communications against eavesdropping.