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.