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Proactive spectrum monitoring for suspicious wireless powered communications in dynamic spectrum sharing networks

This paper studies the proactive spectrum monitoring with one half-duplex spectrum monitor (SM) to cope with the potential suspicious wireless powered communications (SWPC) in dynamic spectrum sharing networks. The jamming-assisted spectrum monitoring scheme via spectrum monitoring data (SMD) transmission is proposed to maximize the sum ergodic monitoring rate at SM. In SWPC, the suspicious communications of each data block occupy multiple independent blocks, with a block dedicated to the wireless energy transfer by the energy-constrained suspicious nodes with locations in a same cluster (symmetric scene) or randomly distributed (asymmetric scene) and the remaining blocks used for the information transmission from suspicious transmitters (STs) to suspicious destination (SD). For the symmetric scene, with a given number of blocks for SMD transmission, namely the jamming operation, we first reveal that SM should transmit SMD signal (jam the SD) with tolerable maximum power in the given blocks. The perceived suspicious signal power at SM could be maximized, and thus so does the corresponding sum ergodic monitoring rate. Then, we further reveal one fundamental trade-off in deciding the optimal number of given blocks for SMD transmission. For the asymmetric scene, a low-complexity greedy block selection scheme is proposed to guarantee the optimal performance. Simulation results show that the jamming-assisted spectrum monitoring schemes via SMD transmission achieve much better performance than conventional passive spectrum monitoring, since the proposed schemes can obtain more accurate and effective spectrum characteristic parameters, which provide basic support for fine-grained spectrum management and a solution for spectrum security in dynamic spectrum sharing network.