On the Performance of Irregular Repetition Slotted ALOHA with an Age of Information Threshold

TL;DR

This paper introduces an age-threshold IRSA protocol for IoT networks that dynamically admits devices based on their age of information, significantly reducing average network AoI compared to existing methods.

Contribution

The paper proposes a novel age-threshold IRSA protocol that uses receiver feedback to improve AoI performance in grant-free IoT communications.

Findings

AT-IRSA more than halves the average network AoI compared to plain IRSA.

The approach outperforms recent feedback-based slotted ALOHA solutions.

Analytical approximation closely matches simulation results.

Abstract

The present paper focuses on an IoT setting in which a large number of devices generate time-stamped updates addressed to a common gateway. Medium access is regulated following a grant-free approach, and the system aims at maintaining an up-to-date knowledge at the receiver, measured through the average network age of information (AoI). In this context, we propose a variation of the irregular repetition slotted ALOHA (IRSA) protocol. The scheme, referred to as age-threshold IRSA (AT-IRSA), leverages feedback provided by the receiver to admit to the channel only devices whose AoI exceeds a dynamically adapted target value. By means of detailed networks simulations, as well as of a simple yet tight analytical approximation, we demonstrate that the approach can more than halve the average network AoI compared to plain IRSA, and offers notable improvements over feedback-based state-of-the-art slotted ALOHA solutions recently proposed in the literature.