Real-Time Implementation and Analysis of Age of Information for Cognitive Radio Internet-of-Things

Abstract

Practical implementation of internet-of-things (IoT) rely on time-critical status updates. A well-known measure of the time-dependency in IoT data is the age of information (AoI). Most of the existing literature considers a theoretical analysis on AoI. Practical considerations and implications of AoI in IoT and cognitive radio (CR)-IoT scenarios have received less attention. In this paper, we consider an experimental Raspberry Pi-based prototype where two sources transmit their status over a common channel – mimicking CR-IoT, whose freshness and relevance are measured by the AoI.For statistical characterization, we let the status updates in each of the nodes to follow uniform, Poisson, and exponential distributions for the inter-packet arrival rate and transmission delay. Further, through real-time experiments based on ThingSpeak, we highlight the dependency of the average AoI on the inter-generation rates and inter-transmission delays.