Timely Data Delivery for Heterogeneous Iot Applications

Internet of Things applications require timely access to information collected from sensors deployed over large geographic areas. However, such applications often experience highly-varying network conditions that prevent the timely delivery of information updates related to source data from sensors. Moreover, IoT applications have different metrics of interest and patterns to request source data. This article explicitly addresses the timely delivery of information updates in heterogeneous IoT scenarios with different application-specific goals. For this purpose, it introduces new metrics based on age of information (AoI) to accurately describe timeliness of updates in such a context. Moreover, it analytically derives optimal update generation policies for different request patterns to minimize the overall update age in an IoT system and maximize fairness of updates. Finally, it carries out a thorough performance evaluation of the proposed policies for representative request patterns with a real-world dataset of Internet connectivity. The obtained results demonstrate that the proposed policies are competitive with those in the state of the art, with a two order of magnitude reduction in energy consumption and up to a <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{1 9. 9 \%}$</tex> higher fairness.