Confidential Transmission Based on Statistical CSI Using DFT Beamforming
Hua Fu, Yanfeng Sun, Xiaoyu Zhang
Abstract
Statistical channel state information (CSI) can be obtained by pre-measuring the user’s channel, unlike instantaneous CSI which is only available after the user has accessed the network. Hence, the statistical CSI can be used to achieve confidential transmission and protect the access process of legitimate users. In this paper, we propose a beam selection scheme based on statistical CSI for discrete Fourier transform beamforming. Assuming that the statistical CSIs of the legitimate user and the eavesdropper are available at the base station, we adopt artificial noise (AN) in transmission and minimize the signal-to-noise-plus-interference ratio of the eavesdropper. The beam selection scheme can be converted into a semidefinite program problem. The performance of the system has been tested in both line-of-sight and non-line-of-sight scenarios using a 5G clustered delay line channel model. The simulation results show that, by transmitting AN, the performance of eavesdropper rapidly degrades when the eavesdropper moves away from the legitimate user.