Peak Age of Information in Priority Queuing Systems

Research output: Contribution to journalArticlepeer-review

37 Scopus citations


We consider a priority queueing system where a single processor serves $k$ classes of packets that are generated randomly following Poisson processes. Our objective is to compute the expected Peak Age of Information (PAoI) under various scenarios. In particular, we consider two situations where the buffer size at each queue is one and infinite, and in the infinite buffer size case we consider First Come First Serve (FCFS) and Last Come First Serve (LCFS) as service disciplines. For the system with buffer size one at each queue, we derive PAoI exactly for the case of exponential service time and bounds (which are excellent approximations) for the case of general service time, with small $k$. For the system with infinite buffer size, we provide closed-form expressions of PAoI for both FCFS and LCFS where service time is general and $k$ could be large. Using those results we investigated the effect of ordering of priorities and service disciplines for the various scenarios. We perform extensive numerical studies to validate our results and develop insights.

Original languageEnglish (US)
Article number9239322
Pages (from-to)373-390
Number of pages18
JournalIEEE Transactions on Information Theory
Issue number1
StatePublished - Jan 2021
Externally publishedYes


  • Age of information
  • performance analysis
  • priority queues

ASJC Scopus subject areas

  • Information Systems
  • Computer Science Applications
  • Library and Information Sciences


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