Peak Age of Information under Tandem of Queues

TL;DR

This paper analyzes the peak age of information in a tandem queue system with memoryless arrivals and services, providing recursive formulas for mean PAoI and AoI under different policies.

Contribution

It introduces a recursive framework to characterize mean PAoI and AoI in tandem queues with no buffers, considering preemptive and non-preemptive policies.

Findings

Derived recursive formulas for mean PAoI and AoI.

Applicable to systems with multiple servers with different service rates.

Provides insights into age performance in tandem queue systems.

Abstract

This paper considers a communication system where a source sends time-sensitive information to its destination via queues in tandem. We assume that the arrival process as well as the service process (of each server) are memoryless, and each of the servers has no buffer. For this setup, we develop a recursive framework to characterize the mean peak age of information (PAoI) under preemptive and non-preemptive policies with $N$ servers having different service rates. For the preemptive case, the proposed framework also allows to obtain mean age of information (AoI).