Interference Management for Physical Layer Security in Heterogeneous Networks

In this paper, we propose an interference management mechanism for physical layer security in a two-tier heterogeneous network (HetNet) system to maximize the secrecy rate of a user under eavesdropping attack. The HetNet system model includes a macro base station and several small base stations, several users and one eavesdropper. Massive multiple-input multiple-output technology is applied in all the base stations. The users and the eavesdropper are each armed with a single antenna. The proposed interference management mechanism takes consideration of transmit beamforming, spectrum reuse and D2D communications. D2D communications are applied around the eavesdropper in the macro cell. An optimization problem is formulated for the secrecy rate maximization under the constraints of quality of services of users associated with base stations and power limitation of base stations. Numerical results show that our proposed interference management mechanism for physical layer security can utilize the interference to improve the secrecy rate of the user under eavesdropping attack.