Age of Information in Internet of Things: A Survey

Abstract

In recent years, the increasing demand to see the status of objects over the Internet leads to an increase in the number of Internet of Things (IoT) applications. The unique nature of IoT, which involves potentially millions of interconnected devices with different data rate, power, bandwidth, and range specifications, requires different performance metrics than those conventionally employed in other communication applications. In conventional wireless communication systems such as cellular networks, performance indicators, including data rate and spectral efficiency, have become decisive, whereas in energy-constrained real-time IoT applications which require low data rate, the freshness of information has become a more prominent characteristic. Age of Information (AoI), which is the elapsed time after the last received packet update was created at the source, has emerged as a fundamental metric for determining the freshness of information and has attracted substantial research interest. In this regard, this article is dedicated to provide an overview of the current state of the art on the use of AoI for the design and optimization of a large variety IoT applications. After a brief introduction of the IoT and AoI fundamentals, this article presents a survey of the research works on common design issues, such as AoI-based optimization, scheduling for IoT networks, application of learning methods in large-scale IoT systems, real-life applications, and experimental results together with a synopsis of potential future applications and research challenges.

Topics & Concepts