Physical Layer Security Scheme Based on Base Station Cooperation in Dense Heterogeneous Networks

Abstract

For preventing the leakage of confidential messages sent to a marcocell user in dense heterogeneous networks, a physical layer security scheme based on base station cooperation is proposed in the paper. To improve transmission rate of confidential messages and make the downlink signals of other legitimate users interfere with eavesdroppers, the beamforming vectors at a macrocell base station and femtocell base stations are jointly optimized. The problem of maximizing the secrecy rate is modeled under the limitations of quality of service(QoS) and base station power. Due to the intractability, this problem is recast into a convex SemiDefinite Program(SDP) problem using the SemiDefinite Relaxation(SDR) technique and the successive convex approximation(SCA) algorithm. Simulation results validate the efficacy and the security of the scheme.