Utility Loss of Information-Critical Prompt Transmission for Semantic Empowered S-IoT

—Prompt transmission initials the status generation and update by the destination when needed, which has the potential to reduce the unnecessary transmission to save the energy cost and keep freshness for the satellite-based Internet of Things (S-IoT) with limited resources. In this paper, we propose a semantic-empowered metric named utility loss of information (UoI) for a multi-state Markov source to capture the freshness, information value, matching situation of transceivers and energy cost, which can simultaneously quantify the age of information (AoI), value loss of diversity states, mismatch of transceivers, and energy cost of transmissions. Then, we design a UoI-critical prompt (UoIP) transmission scheme for terrestrial IoT sensor with multi-state Markov source to generate status and update to the satellite, and derive the average UoI (AUoI) in both periodic and stochastic queries. Moreover, we propose a reliability-enhanced UoIP (Re-UoIP) scheme to further improve the AUoI over time-varying shadowed Rician (SR) fading channel, which can realize the matching of transceivers with one-time long erasure coding retransmission. Simulation results indicate that our Re-UoIP scheme can achieve the optimal tradeoff among freshness, value, matching situation of transceivers and energy cost in both periodic and stochastic query, and outperforms than the state-of-the-art schemes.