Wireless-powered communications (WPCs) are increasingly crucial for extending the lifespan of low-power Internet of Things (IoT) devices. Furthermore, reconfigurable intelligent surfaces (RISs) can create favorable electromagnetic environments by providing alternative signal paths to counteract blockages. The strategic integration of WPC and RIS technologies can significantly enhance energy transfer and data transmission efficiency. However, passive RISs suffer from double-fading attenuation over RIS-aided cascaded links. In this article, we propose the application of an active RIS within WPC-enabled IoT networks. The enhanced flexibility of the active RIS in terms of energy transfer and information transmission is investigated using adjustable parameters. We derive novel closed-form expressions for the ergodic rate and outage probability by incorporating key parameters, including signal amplification, active noise, power consumption, and phase quantization errors. Additionally, we explore the optimization of WPC scenarios, focusing on the time-switching factor and power consumption of the active RIS. The results validate our analysis, demonstrating that an active RIS significantly enhances WPC performance compared to a passive RIS.

翻译：无线供能通信对于延长低功耗物联网设备的寿命日益关键。此外，可重构智能表面能够通过提供替代信号路径来对抗阻塞，从而创造有利的电磁环境。无线供能与可重构智能表面技术的战略整合可以显著提升能量传输与数据传输效率。然而，被动式可重构智能表面在辅助级联链路上遭受双重衰落衰减。本文提出在支持无线供能的物联网网络中应用主动式可重构智能表面。通过引入可调参数，研究了主动式可重构智能表面在能量传输与信息传输方面增强的灵活性。我们推导了遍历速率与中断概率的新闭式表达式，其中纳入了信号放大、主动噪声、功耗及相位量化误差等关键参数。此外，我们探索了无线供能场景的优化问题，重点关注主动式可重构智能表面的时间切换因子与功耗。结果验证了我们的分析，表明相较于被动式可重构智能表面，主动式可重构智能表面能显著提升无线供能通信的性能。