Downlink Secure Transmission with Base Station Cooperation Using Artificial Noise

Abstract

With the development of wireless communication, one of the critical demands is secure transmission especially in downlink communication. In this paper, downlink secure transmission in two-cell base station cooperation multiuser network is studied. The two base stations are fully cooperated and an artificial noise (AN) is added to degrade the eavesdropper(EVE)'s channel. Perfect channel state information (CSI) of all users is known by the base stations and regularized channel inversion (RCI) precoding is used. The close form expression of secrecy sum rate is derived in the large system regime. The regularization parameter and the power allocation ratio are optimized based on larger system regime results. From analysis, base station cooperation network could serve more users per cell in secure transmission than single cell network. The numerical results show large system regime results are accurate even in finite case. In the simulation figures, the analytical optimal results can well approximate to the simulation results.