Semantic communication is an emerging research topic that has gained a wide range of attention recently. Despite this growing interest, there remains a notable absence of a comprehensive and widely-accepted framework for characterizing semantic communication. This paper introduces a new conceptualization of semantic communication and formulates two fundamental problems, which we term language exploitation and language design. Our contention is that the challenge of language design can be effectively situated within the broader framework of joint source-channel coding theory, underpinned by a comprehensive end-to-end distortion metric. To tackle the language exploitation problem, we put forth three approaches: semantic encoding, semantic decoding, and a synergistic combination of both in the form of combined semantic encoding and decoding. Furthermore, we establish the semantic distortion-cost region as a critical framework for assessing the language exploitation problem. For each of the three proposed approaches, the achievable distortion cost region is characterized. Overall, this paper aims to shed light on the intricate dynamics of semantic communication, paving the way for a deeper understanding of this evolving field.

翻译：语义通信是近年来备受关注的新兴研究课题。尽管关注度与日俱增，但目前仍缺乏一个全面且广泛接受的框架来表征语义通信。本文提出了一种语义通信概念的新诠释，并阐述了两个基本问题，我们称之为语言利用与语言设计。我们认为，语言设计的挑战可以有效地置于联合信源信道编码理论的更宽泛框架内，并以一个全面的端到端失真度量为支撑。为解决语言利用问题，我们提出了三种方法：语义编码、语义解码，以及两者协同结合的语义编解码融合。此外，我们建立了语义失真-代价区域，作为评估语言利用问题的关键框架。针对所提出的三种方法，分别刻画了其可达的失真-代价区域。总体而言，本文旨在揭示语义通信的复杂动态，为该领域的发展深化理解铺平道路。