Analytical Framework of AoI Freshness in Scalable Semantic Communications

Recently, age and semantics of information (ASoI) communications utilizing scalable coding have attracted significant academic attention. However, the foundational principles in this domain remain insufficiently explored, despite their critical importance in advancing future wireless communication systems. To address this issue, we propose an analytical framework for general scalable ASoI coding schemes. Specifically, the proposed framework consists of a graphical representation system and a mathematical quantification approach. The introduced representation system allows the procedures of scalable ASoI coding to be illustrated using a straightforward graph. Meanwhile, the proposed mathematical quantification approach enables us to evaluate the freshness of the age of information (Aol) from the perspective of information theory. Consequently, the results of this paper provide not only a comprehensive understanding of the principles underlying scalable ASoI but also an effective tool for evaluating performance and developing schemes.