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Surveillance performance is studied in this paper for a wireless eavesdropping system, where a full-duplex legitimate monitor eavesdrops a suspicious link efficiently with the artificial noise (AN) assistance. Different from the existing work, the suspicious receiver is assumed to be capable of detecting the presence of AN. Once such receiver detects the AN, the suspicious user will stop transmission, which degrades the surveillance performance. Hence, to improve the surveillance performance, AN should be transmitted covertly with a low detection probability. Under these assumptions, an optimization problem is formulated to maximize the eavesdropping non-outage probability under a covert constraint. Based on the detection ability at the suspicious receiver, a novel scheme is proposed to solve the optimization problem using an iterative search. Moreover, we investigate the impact of both the suspicious and the jamming links uncertainties on the covert surveillance performance. Simulations are performed to verify the analyses. We show that the suspicious link uncertainty enhances the surveillance performance, while the jamming link uncertainty can degrade the surveillance performance.

This paper studies digital beam forming (DBF) methods based on phased array. First of all, the basic principle of DBF is introduced, and the signal direction is controlled through realizing DBF. Secondly, different beam forming methods and their limitations and applications are analyzed. Through the comparison and analysis of different parameters, it is proper to adopt linear constrained minimum variance beam forming method in practical application. Finally, the beam width and zero depth of different parameter beam forming methods are analyzed by simulation.

In this paper, a new Slepian-Wolf codec was constructed with spatially coupled Low-Density Parity-Check Convolutional (SP-LDPCC) codes. The approach is based on considering the correlation as a virtual binary erasure channel (BEC) and Binary-Input Additive White Gaussian Noise (BIAWGN)channel and applying the syndrome concept. The system is focusing on the compression of a equal-probable memory less binary source with side information at the decoder. Results obtained through both simulations and theoretical demonstrated that the proposed compression scheme performed better than the classical LDPC codes in asymmetric Slepian-Wolf framework.