Secure Transmission of Wireless Relaying Systems With Jammer and Multiple-User Selection

In this paper, we investigate the secure transmission of wireless relaying systems with multi-destinations and an eavesdropper (Eve) in Nakagami- $m$ fading channels. To protect the confidential message from leaking to the Eve, an intentional interference is sent from a selected destination. We propose two jammer selection schemes under two typical communication scenarios: 1) the channel state information (CSI) of the Eve is unknown, where a jammer is selected based on the CSI between the selected legitimate receiver and the other destination users and 2) the CSI of the Eve is available, where a jammer is selected based on the CSI between the Eve and the other destination users. To assess the performance of the two proposed schemes, we first derive the exact closed-form expressions of intercept probability and outage probability to evaluate the security and the reliability of the system, respectively. In addition, to evaluate the security and reliability as a whole, we propose a new definition of the security–reliability tradeoff, which allows us to easily optimize the power allocation and improve the performance. Finally, simulation results are provided to verify the availability of the proposed schemes.