Minimizing the Age of Two Heterogeneous Sources With Packet Drops Via Cyclic Schedulers

TL;DR

This paper analyzes cyclic scheduling policies for two sources sharing a channel, aiming to minimize the weighted average age of information despite packet drops, and proposes algorithms for near-optimal scheduling.

Contribution

It introduces a Markov chain approach to compute exact AoI for two-source cyclic schedulers and develops algorithms for near-optimal scheduling with channel errors.

Findings

Exact mean AoI computed via Markov chain for two sources.

Algorithm for generating near-optimal cyclic schedulers.

Effective scheduling reduces average AoI despite packet drops.

Abstract

In a communication setting where multiple sources share a single channel to provide status updates to a remote monitor, source transmissions need to be scheduled appropriately to maintain timely communication between each of the sources and the monitor. We consider age-agnostic scheduling policies which are advantageous due to their simplicity of implementation. Further, we focus on a special class of age-agnostic policies, called cyclic schedulers, where each source is scheduled based on a fixed cyclic pattern. We use weighted average age of information (AoI) to quantify the timeliness of communication. We develop a Markov chain formulation to compute the exact mean AoI for the case of two-source cyclic schedulers. Based on the obtained age expression, we develop an algorithm that generates near-optimal cyclic schedulers to minimize the weighted average AoI for two heterogeneous sources, in the presence of channel errors.