Along with the springing up of the semantics-empowered communication (SemCom) research, it is now witnessing an unprecedentedly growing interest towards a wide range of aspects (e.g., theories, applications, metrics and implementations) in both academia and industry. In this work, we primarily aim to provide a comprehensive survey on both the background and research taxonomy, as well as a detailed technical tutorial. Specifically, we start by reviewing the literature and answering the "what" and "why" questions in semantic transmissions. Afterwards, we present the ecosystems of SemCom, including history, theories, metrics, datasets and toolkits, on top of which the taxonomy for research directions is presented. Furthermore, we propose to categorize the critical enabling techniques by explicit and implicit reasoning-based methods, and elaborate on how they evolve and contribute to modern content & channel semantics-empowered communications. Besides reviewing and summarizing the latest efforts in SemCom, we discuss the relations with other communication levels (e.g., conventional communications) from a holistic and unified viewpoint. Subsequently, in order to facilitate future developments and industrial applications, we also highlight advanced practical techniques for boosting semantic accuracy, robustness, and large-scale scalability, just to mention a few. Finally, we discuss the technical challenges that shed light on future research opportunities.

翻译：随着语义赋能通信（SemCom）研究的兴起，学术界和工业界对其在理论、应用、度量标准及实现等多个方面展现出前所未有的浓厚兴趣。本文旨在对SemCom的背景和研究分类体系进行全面的综述，并提供详细的技术教程。具体而言，我们首先回顾相关文献，解答语义传输中“是什么”和“为什么”的问题。随后，我们展示SemCom的生态系统，包括历史、理论、度量标准、数据集与工具包，并在此基础上提出研究方向分类体系。此外，我们将关键使能技术划分为显式与隐式推理方法两类，并详细阐述它们如何演进并贡献于现代内容与信道语义赋能的通信。除回顾和总结SemCom的最新成果外，我们基于整体统一视角，探讨了其与其他通信层级（如传统通信）的关系。为促进未来发展和工业应用，我们还重点介绍了提升语义准确性、鲁棒性及大规模可扩展性等先进实用技术。最后，我们讨论了技术挑战，为未来研究机遇指明了方向。