Enhancing the secrecy performance of the spatial modulation aided VLC systems with optical jamming

In order to enhance the secrecy performance of the spatial modulation (SM) aided visible light communication (VLC) system, an optical jamming aided secrecy enhancement scheme is proposed in this paper, in which transmitter (Alice) sends the optical jamming signals and the confidential signal simultaneously with amplitude and power constraints, wherein the truncated Gaussian distribution is adopted by the optical jamming signals for the considered constraints. Additionally, with finite discrete support set of the channel inputs' distribution, the corresponding secrecy performance is systematically analyzed for the optical jamming aided SM-VLC system, which includes the average mutual information (AMI), the lower bound on AMI and its closed-form expression approximation and the achievable secrecy rate. Furthermore, the power allocation problem for the proposed SM-VLC systems with optical jamming is considered. Finally, extensive simulation results are presented to validate our analytical results and the secrecy versus bit error ratio (BER) trade-off is characterized. (C) 2018 Elsevier B.V. All rights reserved.