An Artificial Noise Scheme for Secure Communication in Heterogeneous D2D and Cellular Networks

In this paper, we investigate the physical layer security scheme in heterogeneous Device-to-Device (D2D) and cellular networks. More specifically, we aim to optimize the secrecy capacity of D2D users in a single cell where the D2D users share downlink resource with cellular users. We assume that base station is equipped with multiple antennas while other nodes are equipped with single antenna, and the eavesdropper is intending to wiretap the information of D2D user. Base station transmits artificial noise as the jamming-aided signal to degrade the wiretap channel such that the security capacity of D2D user could be improved. First, we design the precoding matrix of artificial noise to make sure that the wiretap channel would be degraded while D2D link and cellular link are not influenced. Second, the precoding matrix of desired information signal of cellular link is designed in order to satisfy the quality demand of cellular link. In this part, we propose three schemes according to different criteria. Finally, the optimal power allocation algorithm is provided. Simulation results demonstrate that our scheme could efficiently improve the secrecy capacity of D2D user while the quality demand of cellular user is satisfied.