LAUSR

Proactive eavesdropping via joint jamming and relaying has been proposed to improve the legitimate surveillance performance. However, how will it perform over multiple time slots compared to proactive eavesdropping via jamming remains unknown. To answer this question, proactive eavesdropping via joint jamming and relaying over multiple time slots is investigated with full and causal channel state information (CSI). The problem for maximizing the average eavesdropping rate subject to the peak and average transmit power constraints is investigated, and the online and offline algorithms are proposed. Simulation results confirm that the proposed algorithms are low complex and practically optimal. It is shown that compared to proactive eavesdropping via jamming, the joint jamming and relaying always performs better with full CSI, and performs better with causal CSI when the average transmit power constraint is loose.