Relay selection for optimized cooperative jamming scheme

In this paper, we study the problem of secure dualhop transmission in the presence of an eavesdropper, where a secrecy-enhanced relay selection as well as a destination cooperation are presented to prevent the source information from being eavesdropped. Taking into account the total power budget, a power allocation scheme is investigated to optimize the destination contribution. We present the system performance in terms of secrecy capacity where we derive a closed form expression for its lower bound. Simulation results reveal that a higher power allocation to the jamming signal should be balanced by a closer placement of the relay to the source to get better system performance, and vice versa.