A Cooperative Jamming Based Security Algorithm for Multi-user MIMO Systems

The existing physical layer security algorithm could guarantee secure communication to a certain extent. However, eavesdropper can get more information from legitimate receivers whose channel condition is worse than other users. In order to improve the system's security, a novel physical layer security algorithm based on cooperative jamming for multiuser MIMO system is proposed in this paper. Firstly, a multi-user MIMO system of security is established, combining transmit beamforming and artificial noise. Then, the status of each user's characteristics is described respectively. And users are divided into a secure communications group and interference group for scheduling according to the characteristics of the user's state. Further, interference group assists the base station interference eavesdropper by adjusting the beamforming weights. Simulation results show that the proposed algorithm can increase the secrecy capacity by 2.4bit/s/HZ averagely, which can improve security for multi-user MIMO system.