Legitimate Eavesdropping with Wireless Powered Proactive Full-duplex Eavesdroppers

In this paper, legitimate eavesdropping in a point-to-point suspicious communication network with multiple wireless powered full-duplex legitimate eavesdroppers is investigated. The eavesdroppers are assumed to adopt the power splitting technique to coordinate energy harvesting and information eavesdropping, and use the harvested energy to proactively jam the suspicious communication. For both collusive and non-collusive eavesdroppers, the successful eavesdropping probability is maximized by optimizing the power splitting ratio at each eavesdropper. Heuristic algorithms are proposed to solve the optimization problems. Simulation results are provided to confirm the effectiveness of the proposed algorithms. It is shown that the proposed algorithms outperform the reference algorithms without proactive jamming, especially for non-collusive eavesdroppers with a high energy harvesting efficiency, a high transmit power of the suspicious user, or a large number of eavesdroppers.