Probability Analysis of Age of Information in Multi-hop Networks

TL;DR

This paper derives the probability distribution of Age of Information in multi-hop networks with packet loss, revealing that average or peak AoI metrics can be misleading for assessing information freshness.

Contribution

It provides the first closed-form equations for AoI distribution in N-hop networks with packet loss, extending beyond average or peak AoI analysis.

Findings

Derived closed-form PMF of AoI in multi-hop networks

Verified theoretical results with simulations

Showed limitations of average and peak AoI metrics

Abstract

Age-of-information (AoI) is a metric quantifying information freshness at the receiver. It captures the delay together with packet loss and packet generation rate. However, the existing literature focuses on average or peak AoI and neglects the complete distribution. In this work, we consider a N-hop network with time-invariant packet loss probabilities on each link. We derive closed form equations for the probability mass function of AoI. We verify our findings with simulations. Our results show that the performance indicators considered in the literature such as average or peak AoI may give misleading insights into the real AoI performance.