Enabling Security and High Energy Efficiency in the Internet of Things With Massive MIMO Hybrid Precoding

Recently, the security of Internet of Things (IoT) has been an issue of great concern. Physical layer security methods can help IoT networks achieve information-theoretical secrecy. Nevertheless, utilizing physical security methods, such as artificial noise (AN) may cost extra power, which leads to low secure energy efficiency. In this paper, the hybrid precoding technique is employed to improve the secure energy efficiency of the IoT network. A secure energy efficiency optimization problem is formulated for the IoT network. Due to the nonconvexity of the problem and the feasible domain, the problem is first transformed into a tractable suboptimal form. Then, a secure hybrid precoding energy efficient (SEEHP) algorithm is proposed to tackle the problem. The numerical results indicate that the proposed SEEHP algorithm achieves higher secure energy efficiency compared with three existing physical layer security algorithms, especially when the number of transmit antennas is large.