Achieve Practical Secrecy with Vector Perturbation Precoding

Vector perturbation (VP) precoding which utilizes a scaled Gaussian vector to minimize the effective transmit power is proved can obtain better diversity compared with linear precoding techniques. In this paper, we apply VP precoding in wireless MIMO wiretap channels to obtain practical physical layer security which aims at maximizing eavesdropper’s error probability. The proposed scheme can also avoid performance loss introduced by artificial noise (AN) based secure schemes. New limit of perturbation vector is developed to guarantee practical secrecy and a new sphere decoder is given to meet such limitation. Furthermore, a modified VP scheme is proposed to reduce the complexity introduced by sphere decoder. Simulation results show that the proposed scheme could also achieve practical secrecy as AN based schemes, and better performance is obtained at the intended user with proposed scheme at the cost of computation complexity.