Unmanned aerial vehicles (UAVs) are envisioned to be extensively employed for assisting wireless communications in Internet of Things (IoT) applications. On the other hand, terahertz (THz) enabled intelligent reflecting surface (IRS) is expected to be one of the core enabling technologies for forthcoming beyond-5G wireless communications that promise a broad range of data-demand applications. In this paper, we propose a UAV-mounted IRS (UIRS) communication system over THz bands for confidential data dissemination from an access point (AP) towards multiple ground user equipments (UEs) in IoT networks. Specifically, the AP intends to send data to the scheduled UE, while unscheduled UEs may pose potential adversaries. To protect information messages and the privacy of the scheduled UE, we aim to devise an energy-efficient multi-UAV covert communication scheme, where the UIRS is for reliable data transmissions, and an extra UAV is utilized as a cooperative jammer generating artificial noise (AN) to degrade unscheduled UEs detection. We then formulate a novel minimum average energy efficiency (mAEE) optimization problem, targetting to improve the covert throughput and reduce UAVs' propulsion energy consumption subject to the covertness requirement, which is determined analytically. Since the optimization problem is non-convex, we tackle it via the block successive convex approximation (BSCA) approach to iteratively solve a sequence of approximated convex sub-problems, designing the binary user scheduling, AP's power allocation, maximum AN jamming power, IRS beamforming, and both UAVs' trajectory planning. Finally, we present a low-complex overall algorithm for system performance enhancement with complexity and convergence analysis. Numerical results are provided to verify our analysis and demonstrate significant outperformance of our design over other existing benchmark schemes.
翻译:根据设想,无人驾驶航空飞行器(UAVs)将广泛用于协助互联网上Things(IoT)应用应用的无线通信。另一方面,Thahertz(Thz)启用智能反射表面(IRS)预计是未来5G以上无线通信的核心赋能技术之一,这些无线通信将带来广泛的数据需求应用。在本文中,我们提议在Thz波段上安装UAV挂载的IRS(UIRS)通信系统,用于从接入点(AP)向IoT网络的多个地面用户设备(UES)进行保密数据传播。具体地说,AP打算将数据发送到预定的 UEU,而非定期的US(TH)则可能构成潜在的对手。为了保护信息信息和预定UEUE的隐私,我们的目标是设计一个节能的多功能化多功能化的多功能化秘密通信系统,而额外的UAVA是合作性干扰生成人造噪音(AN) 和不定期电算结果检测。我们随后制定了一个新的最低平均能源效率(AM) 流流流流流流数据化的UAV) 升级的动力化系统, 升级的动力化, 升级的动力化的升级的系统是最终的升级的周期化,我们决定的动力化的动力化的动力化的动力化的升级的升级的状态, 升级的升级的升级的系统,我们最后的升级的升级的动力化的升级的周期化的周期性能,我们决定的升级的动力化的升级的升级的升级的升级的升级的状态。