Channel Modelling for Unmanned Aerial Vehicles

Unmanned aerial vehicles (UAVs) are different from conventional aircraft which are operated by pilots inside them. UAVs are becoming popular worldwide rapidly due to their multi-functional use for both civil and military purposes. UAVs are used for law enforcement, entertainment, emergency search and rescue, transportation, video coverage and scientific applications. In the near future, it is envisioned that UAVs will pave the way for 5G wireless communications and beyond. Communication methods for UAVs are different from conventional air-to-ground (AG) propagation models. Unlike typical cellular communication, UAV channel modelling faces more challenges and different propagation criteria. Thus, it is very important to achieve accurate channel models for AG communication for UAVs. The extensive investigation in the field of AG channel modelling has not been carried out yet. In this thesis paper, a comparative study on the existing channel models and brief description of typical propagation characteristics are given. After that, categorization of environments based on UAV flying areas and UAV classification based on applications are explained. Following that, selected channel models for UAVs are simulated on Matlab and the results are discussed. With the existing channel models, propagation characteristics such as shadowing, and fading are added for the evaluation of link performances. Comparisons of pathlosses among different environments such as urban micro area (UMi), urban macro area (UMa), and rural macro area (RMa) are also shown to have a better idea about results. The results show that, at 50 km of 3D distance and 2 gigahertz (GHz) of carrier frequency, the aggregate pathlosses without large scale shadow fading for UMa, UMi and RMa areas are 186 dB, 184 dB and 164.5 dB, consecutively. However, a coverage area of 4710 m and 3713 m can be achieved in RMa area at 10% of outage probability for downlink (DL) and uplink (UL) parameters, respectively, of LTE link budget at 2 GHz of carrier frequency. At same outage probability and link budget parameters, the coverage area is slightly less in UMa areas and smallest in the UMi areas among these three scenarios