  In recent years, semantic communication is progressively emerging as an
effective means of facilitating intelligent and context-aware communication.
However, current researches seldom simultaneously consider the reliability and
timeliness of semantic communication, where scheduling and resource allocation
(SRA) plays a crucial role. In contrast, conventional age-based approaches
cannot seamlessly extend to semantic communication due to their oversight of
semantic importance. To bridge this gap, we introduce a novel metric: Age of
Semantic Importance (AoSI), which adaptly captures both the freshness of
information and its semantic importance. Utilizing AoSI, we formulate an
average AoSI minimization problem by optimizing multi-source SRA. To address
this problem, we proposed a AoSI-aware joint SRA algorithm based on Deep
Q-Network (DQN). Simulation results validate the effectiveness of our proposed
method, demonstrating its ability to facilitate timely and reliable semantic
communication.
