Age of Information: A New Concept, Metric, and Tool

  title={Age of Information: A New Concept, Metric, and Tool},
  author={Antzela Kosta and Nikolaos Pappas and Vangelis Angelakis},
  journal={Found. Trends Netw.},
In an increasingly networked world in which information is becoming increasingly actual, how can a system know with certainty just how fresh the information on a remote system is? Much work has been done on delay or latency in systems, but only recently has the concept of the freshness of information in or about a system become quantifiable. This is termed the Age of Information. Age of Information provides a whole new set of metrics and tools that can be used to characterize the freshness of… 

Freshness on Demand: Optimizing Age of Information for the Query Process

The Age of Information at Query (QAoI) is defined, a more general metric that fits the pull-based scenario, and its optimization can lead to very different choices from traditional push-based AoI optimization when using a Packet Erasure Channel (PEC).

Query Age of Information: Freshness in Pull-Based Communication

This work considers a pull-based communication model in which the freshness of information is only important when the receiver generates a query, and optimize the Age of Information at Query (QAoI), a metric that samples the AoI at relevant instants, better fitting the pull- based resource-constrained scenario.

Age of Information for Small Buffer Systems

This small note provides an analysis for the AoI of the Pm system which uses a buffer of size m, a single server, operating without service preemption and in a LIFO manner for stored messages.

Rejuvenation and the Age of Information

It is indicated that questions pertaining to sampling costs associated with the age of information can be useful to assess the optimal rejuvenation trigger interval for software systems.

Freshness ratio of information: a new metric for age of information

A new metric, freshness ratio of information (FRoI), is proposed, defined as the fraction of time the age does not exceed a predefined freshness threshold.

Measuring Age of Information on Real-Life Connections

The effect of synchronization error in the measurement and a solution for calculating an estimate of average AoI without any synchronization are discussed.

Only Those Requested Count: Proactive Scheduling Policies for Minimizing Effective Age-of-Information

  • Bo YinShuai Zhang Z. Niu
  • Computer Science
    IEEE INFOCOM 2019 - IEEE Conference on Computer Communications
  • 2019
By decomposing the scheduling problem into multiple computationally tractable subproblems, this work proposes request-aware scheduling policies for static and dynamic request models, respectively, and shows that serving users requests proactively can reduce time-average EAoI in both scenarios.

A Worst-Case Approximate Analysis of Peak Age-of-Information Via Robust Queueing Approach

This work takes an alternative new approach, the robust queueing approach, to analyze the Peak Age-of-Information (PAoI), and derives a new bound on the PAoI in the single-source single-server setting.

How to Measure the Average and Peak Age of Information in Real Networks?

The results show that the proposed method for obtaining the value of AoI and PAoI from experiments is accurate for the M/M/1 queue and a statistical test was conducted to confirm the reliability of this conclusion.

Age- and Deviation-of-Information of Time-Triggered and Event-Triggered Systems

The results show, however, that event-triggered systems can perform equally well as time-trIGgered systems while causing smaller mean network utilization.



The Power of Waiting for More Than One Response in Minimizing the Age-of-Information

  • Yu SangBin LiBo Ji
  • Computer Science
    GLOBECOM 2017 - 2017 IEEE Global Communications Conference
  • 2017
This paper introduces a new Pull model, which is more relevant for certain applications (such as the real-time stock quotes service), where a user sends requests to the servers to proactively "pull" the information of interest, and derives a closed-form formula for computing the expected AoI.

Age of information with a packet deadline

This work introduces a packet deadline as a control mechanism and study its impact on the average age of information for an M/M/1/2 queuing system, analyzing the system for a fixed deadline and derive a mathematical expression for theaverage age.

Optimizing data freshness, throughput, and delay in multi-server information-update systems

It is proved that a preemptive Last Generated First Served (LGFS) policy simultaneous optimizes the age, throughput, and delay performance in infinite buffer queueing systems and age-optimality for the LGFS policy for any finite queue size is shown.

Real-time status: How often should one update?

A time-average age metric is employed for the performance evaluation of status update systems and the existence of an optimal rate at which a source must generate its information to keep its status as timely as possible at all its monitors is shown.

Update or wait: How to keep your data fresh

This work introduces a penalty function to characterize the level of “dissatisfaction” on data staleness, and forms the average age penalty minimization problem as a constrained semi-Markov decision process (SMDP) with an uncountable state space.

On the Age of Information in Status Update Systems With Packet Management

A communication system in which status updates arrive at a source node, and should be transmitted through a network to the intended destination node, using the queuing theory, and it is assumed that the time it takes to successfully transmit a packet to the destination is an exponentially distributed service time.

Effect of Message Transmission Path Diversity on Status Age

A system in which a sensor sends random status updates over a dynamic network to a monitor is studied, and an approximation that is shown to be close to the simulated age of the status age is provided.

Optimizing freshness of information: On minimum age link scheduling in wireless systems

  • Qing HeD. YuanA. Ephremides
  • Computer Science
    2016 14th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt)
  • 2016
This work investigates the age of information in wireless networks and proposes the novel approach of optimizing the scheduling strategy to deliver the information as timely as possible, and proves it is NP-hard in general.

Age of information of multiple sources with queue management

Considering that queuing delay can unnecessarily increase the age of a critical status update, this work proposes here a queue management technique, in which a queue is maintained with only the latest status packet of each source, overwriting any previously queued update from that source.

Effect of message transmission diversity on status age

This work analyzes the status age metric, which characterizes how old the information at the monitor is from the last received status update, and provides an approximation that matches very closely with the simulated age.