I. Introduction
With the rapid development of sensors technology and wireless communication, various Internet of Things (IoT) devices are invented and deployed in many fields to enable the real-time environmental data collection, such as in transportation systems [1], [2], disaster management [3], [4], and construction industry [5], etc. However, in the practices of many large-scale IoT applications, such as mega infrastructure monitoring, landslide monitoring [6], and maritime surveillance, IoT devices are physically distributed in vast areas that even out of the communication signal coverage, which posts great challenges of efficiently collecting data from them.