A Theory of Semantic Communication

Semantic communication is an emerging topic that has received a wide range of attention recently. A systematic widely-accepted characterization of semantic communication, however, is lacking to date. This paper presents a new formulation of semantic communication, where we formulate two fundamental problems, which we call language utilization and language design, for semantic communication. We argue that the problem of language design essentially falls into the scope of the joint source-channel coding (JSCC) theory with a general end-to-end distortion measure. To solve the language utilization problem, we put forth three approaches: semantic encoding, semantic decoding, and combined semantic encoding and decoding (CSED). We formulate the semantic distortion-cost region for the language utilization problem and characterize the achievable distortion-cost regions for the three approaches.