  This paper investigates the physical-layer security for a random indoor
visible light communication (VLC) network with imperfect channel state
information (CSI) and a protected zone. The VLC network consists of three
nodes, i.e., a transmitter (Alice), a legitimate receiver (Bob), and an
eavesdropper (Eve). Alice is fixed in the center of the ceiling, and the
emitted signal at Alice satisfies the non-negativity and the dimmable average
optical intensity constraint. Bob and Eve are randomly deployed on the receiver
plane. By employing the protected zone and considering the imperfect CSI, the
stochastic characteristics of the channel gains for both the main and the
eavesdropping channels is first analyzed. After that, the closed-form
expressions of the average secrecy capacity and the lower bound of secrecy
outage probability are derived, respectively. Finally, Monte-Carlo simulations
are provided to verify the accuracy of the derived theoretical expressions.
Moreover, the impacts of the nominal optical intensity, the dimming target, the
protected zone and the imperfect CSI on secrecy performance are discussed,
respectively.
