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Cooperative Jamming Aided Robust Beamforming for MISO Channels with Unknown Eavesdroppers
Hui Ma, Julian Cheng, Xianfu Wang
Abstract
A robust quality-of-service (QoS) based secure transmission design is investigated for a cooperative jamming aided multiple-input single- output system with unknown eavesdroppers. By assuming legitimate receiver's channel state information (CSI) is imperfect and eavesdroppers' CSI is unavailable, our system design goal is to maximize the power of artificial jamming signals, and to guarantee a minimum QoS at the legitimate receiver. The transmit beamforming vector and covariance matrix of jamming signals are jointly optimized under individual power constraints. As this optimization problem is non-convex, we propose a solution method by using the semidefinite relaxation approach. Numerical results show that, our design, in which the precoding scheme of information transmission is transmit beamforming, outperforms its transmit covariance based counterpart.