Legitimate Surveillance of Suspicious Multichannel DF Relay Networks With Monitor Mode Selection

In this letter, legitimate surveillance of a suspicious multichannel decode-and-forward (DF) relay network is investigated, where the monitor eavesdrops, jams or assists the suspicious communication on each subchannel. The problem of mode selection and transmit power allocation of the monitor for maximizing the eavesdropping rate is first transformed to a more tractable form, and then an optimal algorithm and a suboptimal algorithm are proposed. Simulation results confirm the superiority of the proposed algorithms compared to benchmark algorithms, and show that the suboptimal algorithm is low-complex and achieves the performance very closed to the high-complex optimal algorithm.