Abstract
To legitimately monitor suspicious wireless communications is an important issue. In this letter, we propose a proactive monitoring via jamming scheme over an amplify-and-forward relay network, which consists of a legitimate monitor, a suspicious source, a suspicious relay, and a suspicious destination. Our objective is to design the optimal jamming power to maximize average monitoring rate at the legitimate monitor. For the optimization problem, we propose to find the true optimal jamming power by a bisection search method. Furthermore, we propose an approximate optimal jamming scheme whose closed-form expression on average monitoring rate is theoretically derived. Simulation results demonstrate that our proposed true optimal jamming scheme outperforms passive monitoring and proactive monitoring via constant-power jamming. Furthermore, our proposed approximate optimal jamming scheme achieves almost the same average monitoring rate as true optimal one.