Abstract: |
In several emerging networks and applications ranging from cyber-physical systems to timely data analysis, there has been a surge of interest in the freshness of information for real-time remote monitoring problems. When considering the freshness of information, traditional network performance metrics such as throughput and delay are not always effective. The Age of Information(AoI) metric has become a major research topic on real-time monitoring applications. However, recognizing the shortcomings of AoI, researchers have proposed several new metric of information freshness: for example, Age of Synchronization(AoS), Value of Information of Update(VoIU), Urgency of Information(UoI), Age of Incorrect Information(AoII), and Freshness Ratio of Information(FRoI). In the context of monitoring a binary information source over a delay system with feedback, we consider four different performance metrics: real-time error, AoI, AoII, and FRoI. For each performance metric, we model the delay system as a discrete-time Markov chain and evaluate the performance via stochastic analysis. Extensive numerical results are also provided to compare the four performance metrics under various system parameters. |