Minimizing Quantized Semantic Age of Information (QSAoI) in Foundation Model-Based Semantic Communications
For 6G network designers, this work bridges the gap between semantic and physical layers for low-latency short-packet transmissions, though the improvements are incremental over existing baselines.
The paper introduces a novel metric, Quantized Semantic Age of Information (QSAoI), to capture trade-offs between freshness and semantic efficiency in real-time communication under finite blocklength effects. They propose a foundation model-based framework and an algorithm that dynamically optimizes mixed-precision quantization and blocklength, achieving lower expected QSAoI compared to baselines in simulations.
The emerging techniques of semantic communications and edge computing in 6G networks necessitate a paradigm shift toward co-designed semantic-aware and adaptive resource allocation for short-packet transmissions. However, there is a fundamental gap between the semantic layer and the physical layer under low-latency finite blocklength (FBL) effects. To bridge this gap, we introduce the Quantized Semantic Age of Information (QSAoI), a novel metric that rigorously captures the trade-offs among freshness and semantic efficiency of high-level features in real-time communication in the FBL regime. Guided by this metric, we propose a novel foundation model-based efficient co-designed framework to minimize the expected QSAoI over wireless fading channels in latency-constrained semantic communication. Specifically, we formulate a non-linear joint optimization problem to dynamically optimize the block-wise mixed-precision quantization (MPQ) strategy and the physical blocklength. To efficiently resolve this complex problem, we develop a high-efficiency low-complexity algorithm based on fixpoint inspection and bisection search. Extensive simulations validate that our proposed algorithm dynamically adapts the semantic quantization precision to varying channel conditions, effectively minimizing the expected QSAoI compared to baselines.