Age of Information in Multi-hop Networks with Priorities

TL;DR

This paper analyzes Age of Information in two-hop networks with prioritized updates, deriving bounds and exact expressions to inform the design of age-sensitive multi-hop systems.

Contribution

It provides the first detailed analysis of Age of Information with prioritized traffic in two-hop networks, including bounds and exact age distributions.

Findings

Derived the age distribution and peak age bounds for prioritized updates.

Provided tight upper and lower bounds for priority packet age.

Obtained exact expressions for non-critical packet age with general service distributions.

Abstract

Age of Information is a new metric used in real-time status update tracking applications. It measures at the destination the time elapsed since the generation of the last received packet. In this paper, we consider the co-existence of critical and noncritical status updates in a two-hop system, for which the network assigns different scheduling priorities. Specifically, the high priority is reserved to the packets that traverse the two nodes, as they experience worse latency performance. We obtain the distribution of the age and its natural upper bound termed peak age. We provide tight upper and lower bounds for priority updates and the exact expressions for the non-critical flow of packets with a general service distribution. The results give fundamental insights for the design of age-sensitive multi-hop systems.