Medium Access Control Protocols for Unmanned Aerial Vehicle-Aided Wireless Sensor Networks: A Survey

Wireless sensor networks (WSNs) have been broadly used in various areas of commercial applications as well as public services. Furthermore, emerging unmanned aerial vehicles (UAVs) have been combined into many existing technologies. By employing UAVs in WSNs, sensor data can be effectively collected and the network lifetime is prolonged with reduced energy consumption. In the UAV-aided WSNs (UWSNs), medium access control (MAC) is very important because it affects not only the system performance but also the energy efficiency in battery-powered sensor nodes. It should be noted that the tiny sensor nodes are typically disposable and their batteries are not replaceable in most applications. Thus, a number of MAC protocols with different objectives have been designed for UWSNs. To the best of the authors' knowledge, there is no survey on MAC protocols for UWSNs in the literature. In this paper, the various MAC protocols for UWSNs are extensively investigated and qualitatively compared with each other in terms of major features, characteristics, and pros and cons. Moreover, open issues and challenges in the design of the MAC protocols for the UWSNs are discussed.