Programmable wireless environments (PWEs) utilize internetworked intelligent metasurfaces to transform wireless propagation into a software-controlled resource. In this article, the interplay is explored between the user devices, the metasurfaces, and the PWE control system from the theory to the end-to-end implementation. This article first discusses the metasurface hardware and software, covering the complete workflow from the user device initialization to its final service via the PWE. Furthermore, to be compatible with the 5G and 6G wireless systems, the software-defined networking (SDN) paradigm is extended to achieve scalable internetworking and central control in PWE deployments with multiple metasurfaces and multihop communication. Subsequently, the set of SDN foundations is exploited in order to abstract the physics behind PWEs and a theoretical framework is established to describe and manipulate them in an algorithmic form. This can lead to smart radio environments that are readily accessible from various engineering disciplines, facilitating their integration into existing networks, wireless systems, and applications. This article is concluded by outlining strategies for the optimal placement of metasurfaces within a PWE-controlled space, open challenges in PWE security, specialized SDN integration issues, and theoretical problems toward the graph-driven modeling of PWEs.

中文翻译：

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软件定义的可重构智能表面：从理论到端到端实施


可编程无线环境 (PWE) 利用联网的智能超表面将无线传播转换为软件控制的资源。在本文中，从理论到端到端实现，探讨了用户设备、超表面和 PWE 控制系统之间的相互作用。本文首先讨论超表面硬件和软件，涵盖从用户设备初始化到通过 PWE 提供最终服务的完整工作流程。此外，为了与 5G 和 6G 无线系统兼容，软件定义网络 (SDN) 范式得到扩展，以在具有多个超表面和多跳通信的 PWE 部署中实现可扩展的互联和中央控制。随后，利用 SDN 基础集来抽象 PWE 背后的物理原理，并建立一个理论框架来以算法形式描述和操作它们。这可以形成可以从各种工程学科轻松访问的智能无线电环境，从而促进它们集成到现有网络、无线系统和应用程序中。本文最后概述了 PWE 控制空间内超表面的最佳放置策略、PWE 安全方面的开放挑战、专门的 SDN 集成问题以及 PWE 图形驱动建模的理论问题。