In this letter, secure beamforming in a multiple intelligent reflecting surfaces (IRSs)-aided millimeter-wave (mmWave) system is investigated. In this system, the secrecy rate is maximized by controlling the on-off status of each IRS as well as optimizing the phase shift matrix of the IRSs. This problem is posed as a joint optimization problem of transmit beamforming and IRS control, whose goal is to maximize the secrecy rate under the total transmission power and unit-modulus constraints. The problem is difficult to solve optimally due to the nonconvexity of constraint conditions and coupled variables. To deal with this problem, we propose an alternating optimization (AO)-based algorithm based on successive convex approximation (SCA) and manifold optimization (MO) technologies. Numerical simulations show that the proposed AO-based algorithm can effectively improve the secrecy rate and outperforms the traditional single IRS-aided scheme.
@article{arxiv.2006.14851,
title = {Secure Beamforming for Multiple Intelligent Reflecting Surfaces Aided mmWave Systems},
author = {Yue Xiu and Jun Zhao and Chau Yuen and Zhongpei Zhang and Guan Gui},
journal= {arXiv preprint arXiv:2006.14851},
year = {2020}
}
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This paper appears in IEEE Communications Letters. Please feel free to contact us for questions or remarks. https://doi.org/10.1109/LCOMM.2020.3028135/