Intelligent reflecting surfaces (IRSs), active and/or passive, can be densely deployed in complex environments to significantly enhance wireless network coverage for both wireless information transfer (WIT) and wireless power transfer (WPT). In this letter, we study the downlink WIT/WPT from a multi-antenna base station to a single-antenna user over a multi-active/passive IRS (AIRS/PIRS)-enabled wireless link. In particular, we aim to optimize the location of the AIRS with those of the other PIRSs being fixed to maximize the received signal-to-noise ratio (SNR) and signal power at the user in the cases of WIT and WPT, respectively. We derive the optimal solutions for these two cases in closed-form, which reveals that the optimal AIRS deployment is generally different for WIT versus WPT. Furthermore, both analytical and numerical results are provided to show the conditions under which the proposed AIRS deployment strategy yields superior performance to other baseline deployment strategies as well as the conventional all- PIRS enabled WIT/WPT.

翻译：智能反射面（IRSs，包括有源和无源）可在复杂环境中密集部署，以显著增强无线信息传输（WIT）和无线功率传输（WPT）的无线网络覆盖范围。本文研究在多活性/无源IRS（AIRS/PIRS）赋能的无线链路中，从多天线基站到单天线下行WIT/WPT问题。特别地，我们旨在优化AIRS的位置，同时固定其他PIRS的位置，以分别在WIT和WPT场景下最大化用户接收的信噪比（SNR）和信号功率。我们以闭式解形式推导了这两个场景下的最优解，结果表明AIRS的最优部署在WIT与WPT场景下通常存在差异。此外，通过解析和数值结果展示了所提出的AIRS部署策略相较于其他基准部署策略以及传统全PIRS赋能WIT/WPT方案取得更优性能的条件。