Secrecy Capacity Analysis Of Visible Light Communication

With the wide application of LED(Light Emitting Diode)in lighting field,VLC(Visible Light Communication)has attracted wide attention recently.Due to the combination of communication and lighting,VLC is regarded as one of the most important wireless communication technologies in the future.In the past decade,VLC has achieved rapid development in many aspects.However,there are still some deficiencies in physical layer security.In this paper,the physical layer security of visible light communication is studied.The main contents of this paper are as follows:Firstly,the secrecy capacity of visible light communication without peak optical intensity constraints is studied.In this chapter,two lower bounds and one upper bound of the secrecy capacity of are studied.The numerical results show that the upper and lower bounds are tight.The asymptotic behavior is also analyzed.The analysis show that the gap is small between upper and lower bounds at high SNR(Signal to Noise Ratio).Meantime,the secure region and the insecure region are discussed.they plays an important role in guiding the placement of transmitter and legitimate receiver in indoor visible light communication system.Secondly,the secrecy capacity of visible light communication with peak optical intensity constraints is studied.Similarly,lower bound,upper bound,asymptotic behavior and secure region are studied.Meantime,the upper and lower bound are also tight.Differently,the gap between the upper and lower bound are smaller than the gap between the upper and lower bound without peak optical intensity constraints.At last,the secrecy capacity for indoor VLC is further investigated by considering the spatially random receivers and imperfect CSI(Channel State Information).The lower bound of ergodic secrecy capacity is derived in this section,and the simulation results are verified by Monte-Carlo.Meantime,the result shows that the lower bound of ergodic secrecy capacity increases as the radius of the protected area,the dimming target and uncertain parameter between Alice and Bob.