A survey of UAV-based data collection: Challenges, solutions and future perspectives.

Internet of Things (IoT) generates unlimited data, which should be collected and forwarded towards a central controller (CC) for further processing and decision-making. Nevertheless, the unique features of IoT devices, such as their limited energy capacity, large-scale deployment, and prospective mobility, introduce new challenges and constraints, resulting in unoptimized data gathering. Therefore, as a forthcoming solution, Unmanned Aerial Vehicles (UAVs) could be dispatched as auxiliary devices, and the benefits of their potential are fully exploited, such as movement flexibility, mitigation of IoT communication burden, minimization of data collection (DC) delay, powering IoT devices, and efficient delivery of collected data. The current state-of-the-art has a noticeable gap that hinders the systematic reviews of UAV-based DC schemes. To bridge this gap, this survey provides an extensive analysis of UAV-based DC schemes to light up the topic. We first outline the main characteristics of UAV networks, which have to be considered when designing an efficient UAV-based DC scheme. Also, we highlight the main challenges that, if considered during the data gathering process, can significantly enhance the assistance of UAVs to IoT devices. We then describe various UAV-based DC applications with their key features. Next, our paper comprehensively discusses UAV-based DC schemes according to a proposed taxonomy. Finally, we discuss current problems, difficulties, and potential future directions for UAV-based DC research.