标题：Robust QoS-Based Transmit Beamforming Design in MISO Wiretap Channels
作者：Ma, Hui; Ma, Piming
作者机构：[Ma, Hui; Ma, Piming] Shandong Univ, Sch Informat Sci & Engn, Jinan 250100, Peoples R China.
会议名称：4th International Conference on Wireless Communications and Signal Processing (WCSP)
会议日期：OCT 25-27, 2012
来源：2012 INTERNATIONAL CONFERENCE ON WIRELESS COMMUNICATIONS AND SIGNAL PROCESSING (WCSP 2012)
关键词：physical layer security; cooperative jamming; robust beamforming; convex; optimization
摘要：In this paper, a robust quality-of-service (QoS) based secret transmit beamforming design problem is discussed for a multiple-input single-output (MISO) system which works under cooperative jamming (CJ) scheme with a helper transmitting jamming signals to confuse the eavesdropper. For the channel state information (CSI), we assume that the CSI for the legitimate link is available and the CSI for the wiretap channel is imperfect. Our system design goal is to optimize the worst-case performance of the network under the situation: minimizing the signal-to-interference-and-noise ratio (SINR) at the eavesdropper and meanwhile guaranteeing the SINR at legitimate receiver. Thus the spatial distribution of jamming signals and the beamforming vector of source are jointly optimized under a total power constraint. As this optimization problem is difficult to tackle, a method is proposed with proofs to obtain exact solver of it. Our analysis reveals that optimizing the beamforming vector of source is a better strategy compared to optimizing the spatial covariance matrix of information signals. Numerical results affirm this and show the advantage of robust transmit designs compared to a non-robust approach in lowering the SINR at the eavesdropper in the presence of channel uncertainties.