Utility Loss of Information Minimization for Semantic-Empowered Satellite-Integrated Internet

In response to the requirements of precise information conveying and goal-oriented transmitting with minimal cost for the upcoming satellite-integrated Internet, we focus on a semantic communication metric named utility loss of information (UoI), which is generalized to capture the tradeoff of the value and energy loss of information. The former is quantified by the duration and severity of mismatch transceivers, and the latter is evaluated by unnecessary data generation and transmissions. To achieve the optimal tradeoff between value and energy loss of information for status update, we formulate a joint optimization problem to design a UoI-optimal policy to generate and transmit data for a multi-state Markov source. By regarding the limited energy, we transform the above problem to a constrained Markov decision process (CMDP), and rigorously prove the UoI-optimal policy has a dual-threshold structure. Then, we derive the closed-form expressions for average UoI and generation and transmission ratio. Moreover, we propose a simplified relative value iteration (SRVI) algorithm based on the theoretical derivations, combined with the bisection search to find two optimal thresholds for the UoI-optimal policy. Simulation results verify that our UoI-optimal policy achieves the optimal tradeoff among timeliness, reliability, and energy efficiency, and outperforms several state-of-the-art semantic-aware policies.