IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC)
Multi-Cell Processing and Artificial Noise for Secure Transmission in Downlink Multi-cell MIMO Systems under Imperfect CSI
Juan Bai, Tao Dong, Qin Zhang, Xuefei Zhang, Yanhong Lin
Abstract
For 5G wireless networks, one of the critical demands is security and privacy, which are particularly in multi-cell multi-user MIMO downlink communications. In this paper, we study secure transmission in the downlink of a multi-cell MIMO cellular network under imperfect channel state information (CSI). Multi-Cell Processing (MCP) and an artificial noise (AN) are employed for secrecy enhancement. For MCP, the BSs share the channel information and data symbols for all users to control inter-cell interference and information leakage. AN is added to degrade the eavesdropper's channel. Based on regularized channel inversion (RCI) precoding, we derive the concise formulas for the signal-to-interference plus noise ratio (SINR) at a legitimate user and an eavesdropper, and the achievable secrecy sum-rate with MCP and AN. Furthermore, we obtain their corresponding approximation in large-system regime. It shows that secrecy sum-rate can be greatly improved with MCP and AN under imperfect CSI, especially in high signal-to-noise ratio (SNR), the secrecy sum-rate stays a constant. The analytical results are validated with finite-size system by simulation.