Whittle Index Based Age-of-Information Aware Scheduling for Markovian Channels

The focus of this work is on minimizing the time average of the weighted sum of the Age-of-Information in a multi-sensor system in the setting where all sensors report their measurements to a central monitoring station using a shared communication channel. We consider multiple information settings including complete CSI/delayed CSI/no CSI and two stochastic channel evolution models, i.e., i.i.d. channels and Markovian channels. In all settings considered, we prove the indexability of the scheduling problem. In addition, we compute the Whittle Index in closed form for some of the settings. Indexability for Markovian channels for the objective of minimizing AoI is a key contribution of this work. Further, under i.i.d. channels, we propose a novel efficient implementation for the Whittle Index-based policy. We use simulations to show that Whittle Index-based scheduling policies either outperform or match the performance of the state-of-the-art policies for all the settings considered.