Abstract
Legitimately surveilling suspicious wireless communications is important for public security. In this paper, we propose a proactive legitimate unmanned aerial vehicle (UAV) monitor surveilling via a jamming scheme in suspicious decode-and-forward relay networks. To maximize average surveilling rate, we derive a closed-form optimal solution of jamming power given the position of the legitimate UAV monitor. With the derived optimal jamming power, we show that optimal position and jamming power are related to the height of the UAV monitor. Given the height of the UAV monitor, we theoretically prove that the optimal position of the monitor can be found by bisection search. From the numerical results, we show that the optimal position of the monitor found by bisection search achieves exactly the same average surveilling rate as that found by the 1-D search. It is also found that our proposed surveilling scheme with optimal position and jamming is superior to the surveilling scheme with a fixed position and the passive surveilling scheme.