Hücresel Haberleşme Sistemlerinde İHA Haberleşme Kanal Modellerinin İncelenmesi

Abstract

There are a number of challenges involved in establishing air corridors for flight routes and integrating unmanned aerial vehicles into an automated system that will not pose a threat to the society. The primary objective of this thesis study is to examine the received power and coverage area provided by ground-based base stations up to heights of 120 meters for UAV applications. Therefore, how we will communicate with unmanned aerial vehicles is one of the most crucial factors to take into account. Among the research topics are the usefulness of terrestrial communication systems for drone communication, the received signal power values, and the sufficiency of coverage at various altitudes.

Due to the dynamic nature of Unmanned Aerial Vehicles, the main goal in this study is to create a physical channel model between the base stations we use in terrestrial communication systems and Unmanned Aerial Vehicles for different scenarios. In order to model the air coverage that will be affecting the low-altitude unmanned aerial vehicles for next-generation communication systems, the features such as path losses and probabilities of the multi-path signals that undergo different interactions were examined by using realistic approaches while modelling the physical channel in different scenarios. The objective is to arrive at a conclusion within acceptable errors. Due to that, a simulation model of a terrestrial base station consisting of three sectors is prepared on a Manhattan-grid city model, which is generated according to different statistical parameters. Three-dimensional ray tracing method was used for different altitudes and buildings.

In addition, field studies are carried out for 3 different altitudes in a rural area with multiple base stations. This field is modeled in the MATLAB environment. The missing information during the modelling is completed according to the ITU-R recommendations and a mathematical path-loss model is created. By comparing the simulation data and measurement data in terms of RSRP RSRQ, the validity of the model is determined with acceptable mean average error. Frequency transitions between two cells were also evaluated. Considering the electromagnetic properties of the vegetation, the excessive attenuation due to vegetation is modeled within the ground reflected signals. The thesis work investigation of uav communication channel models in cellular communication systems is concluded by making additions to the two-ray model.