Secure Communications in Cooperative D2D Networks by Jointing Wyner’s Code and Network Coding

Abstract

Due to the broadcast nature of wireless device-to-device networks, the transmission of private information is threatened by the exterior eavesdropping. Targeting at this problem, we jointly exploit the Wyner’s code and the linear network coding, in this paper, to improve the security. The function of the Wyner’s code requires the legitimate channel better than the eavesdropper’s channel, so we propose a novel relay selection scheme to achieve this objective. Specifically, two groups of relays have been selected. Relays in one of the groups are selected to forward the private information, and relays in the other group are selected to transmit artificial noise. In this way, we make sure that the signal-to-noise ratio (SNR) at the legitimate receiver is larger than a target value but the SNR at the eavesdropper has a certain probability less than the target value so that the security can be enhanced. Moreover, focusing on the problem that the Wyner’s code cannot achieve security if the SNR at the eavesdropper is larger than the target value, we propose a network coding method. In this method, the message to be transmitted is divided into multiple parts, and then these parts are correlated with each other by using network coding. Thus, the eavesdropper also cannot decode the private information even its SNR larger than the target value. We analyze the secrecy outage probability in theory, and the simulation results are provided to confirm our analysis.