Measurement based air to air and air to ground drone communication channel modeling

Abstract

Unmanned aerial vehicle (UAV) has become widespread and has brought various communication problems. Especially the wireless communication area receiver and transmitter design is of great importance for UAV–Ground and UAV–UAV scenarios. Furthermore, powered by the advances in microelectronics technologies, UAVs provide a vast variety of services ranging from surveillance to delivery in both military and civilian domains. It is clear that a successful operation in those services relies heavily on wireless communication technologies. Even though wireless communication techniques could be considered to reach a certain level of maturity, wireless communication links including UAVs should be regarded in a different way due to the peculiar characteristics of UAVs such as agility in 3D spatial domain and versatility in modes of operation. Such mobility characteristics in a vast variety of environmental diversity render links including UAV different from those in traditional, terrestrial mobility scenarios. Furthermore, UAVs are critical instruments for network operators in order to provide basic voice and short messaging services for narrow band communication in and around disaster areas. It is obvious that such widespread use of UAVs under different scenarios and environments requires a better understanding the behavior of the communication links that include UAVs. In addition to, drones are emerging as a rapid solution to enable or support communication services in various scenarios such as sports events, natural disasters, macro base station malfunctions. Any operation scenario for drones requires a reliable, secure, and resilient wireless link to guarantee capacity and performance for users, which can only be achieved by obtaining detailed knowledge about the propagation channel. Therefore, in Chapter 3, different measurement systems have been tried to be created for UAV channel modeling, but it has become difficult to obtain measurement based results due to physical problems arising from UAV and design of mobile measurement system. In addition, channel measurement systems with Universal Software Based Hardware (USRP), one of the software based radio devices and challenges will be mentioned. In Chapter 4, details of a measurement campaign designed to collect data for large-scale propagation characterization of air–to–ground links operated by UAV at 446MHz are given. Data collection, post-processing, and measurement results are provided. Chapter 5 investigates the large-scale channel propagation statistics for the LOS A2A drone communications. We conducted a measurement campaign at 5.8 GHz, using software defined radio based channel sounders and commercially available drones. To determine the path loss exponent, frequency-based, time-based and time–frequency based methods are utilized. Accuracy of the proposed method is verified under ideal conditions in a well-isolated anechoic chamber before the actual measurement campaign to verify the performance in a free space path loss environment. The path loss exponent for A2A wireless drone channel is estimated with these verified methods.