Age of Information: Whittle Index for Scheduling Stochastic Arrivals

TL;DR

This paper introduces a low-complexity scheduling algorithm for minimizing the age of information in wireless networks, using the Whittle index derived for stochastic arrivals, which closely approximates optimal performance.

Contribution

It derives a closed-form Whittle index for age minimization in stochastic settings and proposes a practical scheduling algorithm based on it.

Findings

The Whittle index is successfully derived and shown to be indexable.

The proposed scheduling algorithm closely approximates age-optimal scheduling.

Experimental results demonstrate near-optimal performance of the algorithm.

Abstract

Age of information is a new concept that characterizes the freshness of information at end devices. This paper studies the age of information from a scheduling perspective. We consider a wireless broadcast network where a base-station updates many users on stochastic information arrivals. Suppose that only one user can be updated for each time. In this context, we aim at developing a transmission scheduling algorithm for minimizing the long-run average age. To develop a low-complexity transmission scheduling algorithm, we apply the Whittle's framework for restless bandits. We successfully derive the Whittle index in a closed form and establish the indexability. Based on the Whittle index, we propose a scheduling algorithm, while experimentally showing that it closely approximates an age-optimal scheduling algorithm.