Contents I. Introduction
With the popularity of the Internet of Things (IoT) and wireless networks, many real-time IoT applications (e.g., video surveillance) have emerged [1]. Timely and fresh data updates are critical to the smooth operation of these applications. To measure the freshness of information obtained by the destination node, the concept of age of information (AoI) has been introduced recently [2]. Particularly, AoI is a new performance metric that refers to the time elapsed since the generation of the last successfully received status update message. It can effectively measure the information freshness and reflect the timeliness of real-time applications in transmitting status information updates to specified devices [3]. In practical applications, many information updates (e.g., images and videos) often require computation-intensive processing to extract useful information. However, as the source nodes, wireless devices often have difficulty in performing timely processing due to their limited computing power. Mobile edge computing speeds up the processing of update tasks by deploying edge servers near wireless devices [4]. By offloading computation-intensive update tasks to the edge server, wireless devices reduce the latency of processing update tasks and improve the freshness of information [5].
