Biblio

This paper investigates the physical-layer data secure transmission for indoor visible light communications (VLC) with simultaneous wireless information and power transfer (SWIPT) and random terminals. 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) is employed to evaluate the system performance. A closed-from expression for the lower bound of the SOP is obtained. For the derived lower bound of SOP, the theoretical results match the simulation results very well, which indicates that the derived lower bound can be used to evaluate the secrecy performance. Moreover, the gap between the results of the lower bound and the exact simulation results is also small, which verifies the correctness of the analysis method to obtain the lower bound.

In the paradigm of network coding, information-theoretic security is considered in the presence of wiretappers, who can access one arbitrary edge subset up to a certain size, referred to as the security level. Secure network coding is applied to prevent the leakage of the source information to the wiretappers. In this paper, we consider the problem of secure network coding for flexible pairs of information rate and security level with any fixed dimension (equal to the sum of rate and security level). We present a novel approach for designing a secure linear network code (SLNC) such that the same SLNC can be applied for all the rate and security-level pairs with the fixed dimension. We further develop a polynomial-time algorithm for efficient implementation and prove that there is no penalty on the required field size for the existence of SLNCs in terms of the best known lower bound by Guang and Yeung. Finally, by applying our approach as a crucial building block, we can construct a family of SLNCs that not only can be applied to all possible pairs of rate and security level but also share a common local encoding kernel at each intermediate node in the network.