Intelligent reflecting surface (IRS) is a promising technology for achieving spectrum and energy efficient wireless networks cost-effectively. While most existing works focus on exploiting IRS to enhance the performance of wireless information transmission (WIT), the high beamforming gain achieved by passive IRS is also appealing for boosting the efficiency of radio-frequency (RF) based wireless power transfer (WPT) and improving its service coverage. Although IRS-aided WPT shares certain similar characteristics with IRS-aided WIT, they also differ significantly in terms of the design objectives, transmitter/receiver architectures and hardware/power constraints, and so on, which thus may lead to distinct solutions in practice. In this paper, we provide a tutorial overview on IRS-aided WPT and its more complicated integrations with WIT, namely IRS-aided simultaneous wireless information and power transfer (SWIPT) and IRS-aided wireless powered communication networks (WPCNs), from the communication and signal processing perspective. In particular, we identify their fundamental challenges in e.g. passive reflection optimization and channel estimation, propose potential solutions and draw useful insights for practical design. Furthermore, we point out important directions worthy of further investigation in future work.

中文翻译：

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智能反射面辅助无线能量与信息传输：概述

智能反射面 (IRS) 是一种很有前途的技术，可用于经济高效地实现频谱和能源高效的无线网络。虽然大多数现有工作都集中在利用 IRS 来提高无线信息传输 (WIT) 的性能，但无源 IRS 实现的高波束成形增益也对提高基于射频 (RF) 的无线电能传输 (WPT) 和提高服务覆盖率。尽管 IRS 辅助 WPT 与 IRS 辅助 WIT 具有某些相似的特征，但它们在设计目标、​​发射器/接收器架构和硬件/功率限制等方面也存在显着差异，因此在实践中可能会导致不同的解决方案。在本文中，我们提供了有关 IRS 辅助 WPT 及其与 WIT 更复杂集成的教程概述，从通信和信号处理的角度来看，即 IRS 辅助的同步无线信息和电力传输 (SWIPT) 和 IRS 辅助的无线供电通信网络 (WPCN)。特别是，我们确定了他们在被动反射优化和信道估​​计等方面的基本挑战，提出了潜在的解决方案，并为实际设计得出了有用的见解。此外，我们指出了值得在未来工作中进一步研究的重要方向。提出潜在的解决方案并为实际设计得出有用的见解。此外，我们指出了值得在未来工作中进一步研究的重要方向。提出潜在的解决方案并为实际设计得出有用的见解。此外，我们指出了值得在未来工作中进一步研究的重要方向。