Research On Energy Harvesting And Physical Layer Security For Visible Light Communication

Indoor visible light communications(VLC)has a natural advantage in simultaneous lightwave information and power transfer(SLIPT)due to its threefold roles,i.e.,illumination,information transmission,and light power transfer.In this paper,based on indoor VLC and considering physical layer security and power transfer,the tradeoff between the secrecy capacity(SC)and the harvested energy(HE)is investigated and further analysis is made on the more practical scenario of random terminals.Also,a scheme to improve the security transmission performance of the system is proposed.?.Tradeoff between the SC and the HE: An indoor VLC system consisting of a transmitter,a legitimate receiver,and an eavesdropper is established.The legitimate receiver can perform information transmission and light power transfer simultaneously,while the eavesdropper is just an information eavesdropping receiver.Under the nonnegativity and the dimmable average optical intensity constraint,a lower bound of the average SC is derived.By employing the dynamic power splitting(DPS)for the legitimate receiver,the closed-form expression of the average HE is obtained.After that,the SC-HE region for the DPS receiver is constructed.As the variants of the DPS receiver,the time switching(TS),static power splitting(SPS)and on–off power splitting(OPS)receivers are provided,and the corresponding SC-HE regions are also obtained.As a benchmark,the performance upper bound of the SC-HE region for any practical receiver is derived.The simulation results show that the performance of the OPS receiver always outperforms that of the other receivers.The DPS and SPS receivers achieve the same performance.The TS receiver is the worst receiver when HE is small,but it is the best receiver when HE is large.Moreover,the impacts of the dimming target,the estimated error,signal processing noise,and the nominal optical intensity on system performance are discussed.?.Secure transmission and energy havesting in random terminals scenario: A typical indoor VLC system including one transmitter,one desired information receiver and one energy receiver is considered.The two receivers are randomly deployed on the floor,and the random channel characteristics is analyzed.Based on the possibility that the energy receiver is a passive information eavesdropper,the secrecy outage probability(SOP)and the average secrecy capacity(ASC)are employed to evaluate the system performance.A closed-form expression for the lower bound of the SOP and an exact closed-form expression for the ASC are derived,respectively.To further improve the physical-layer security,a protected zone based scheme is proposed,and then the SOP and the ASC are re-derived.By using Monte-Carlo simulations,the accuracy of the derived lower bound of SOP and the exact ASC are verified.Moreover,numerical results show that the security of the VLC system significantly improves by employing the protected zone.