Proactive Eavesdropping Over OFDM-Based Bidirectional Suspicious Communication Channels

In this letter, proactive eavesdropping of an orthogonal frequency division multiplexing (OFDM)-based bidirectional point-to-point suspicious communication link is studied. The problem of joint successive interference cancelation (SIC) decoding ordering and jamming power allocation at the monitor for maximizing the weighted sum eavesdropping rate is formulated as mixed-integer nonlinear programming and then transformed to more tractable zero-one integer programming. A heuristic suboptimal algorithm and an optimal algorithm based on the branch-and-bound method are proposed. Simulation results show the advantageous of the proposed algorithms compared to the benchmarks, and also show that both algorithms are low-complex, and the suboptimal algorithm has further lower complexity and achieves almost the same performance as the optimal algorithm.