Public defence in Radio Engineering, M.Sc.(Tech.) Pasi Koivumäki

The title of the thesis: Radio Wave Propagation Simulations Based On Point Clouds – Methods, Experimental Validations and Applications To Radio Link Design

Doctoral student: Pasi Koivumäki
Opponent: Prof. Conor Brennan; Dublin City University, Ireland
Custos: Prof. Katsuyuki Haneda, Aalto University School of Electrical Engineering, Department of Electronics and Nanoengineering

The constantly increasing demand for wireless transfer of information and ubiquity of smart devices has resulted in spectrum shortage at the sub-6 GHz frequencies. The fifth-generation (5G) of wireless communications aims to solve the problem by utilizing higher frequency bands and spatial re-use of bandwidth with denser networks. To reliably plan deployment of new technologies and evaluate their performance, novel methods of modeling the behavior of radio channels must be explored. This thesis presents results of studying and modeling the propagation of radio waves in indoor, outdoor and outdoor-to-indoor environments at frequencies spanning from 2.45 GHz to 120 GHz. 

The primary focus of this thesis is the utilization of laser-scanned point clouds in accurately simulating propagation of radio waves though the environment. The point cloud is a representation of the environment with points as opposed to polygons, the convention in propagation simulations. While an established topic in the field of computer vision, the point cloud is a relatively unstudied topic in propagation simulations. A point cloud is obtained by scanning the environment with a laser-beam, which captures the small and often overlooked details of the environment. This warrants the development of new simulation methods specifically for point clouds. The simulations are verified to yield accurate results with comparisons to measurements. The secondary focuses of this thesis are the measurement of radio channels and applications of radio channel simulations in radio link design. 

The thesis consists of nine peer-reviewed publications that address interesting challenges in radio channel modeling, including, for example, the processing of point clouds to be suitable for propagation simulations, modeling of line-of-sight probability in urban micro-cells, simulation of outdoor-to-indoor coverage, and spatial similarity of radio channels across frequency.

Keywords: Point cloud, propagation, ray-tracing, ray-launching

Thesis available for public display 10 days prior to the defence at: https://aaltodoc.aalto.fi/doc_public/eonly/riiputus/

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Doctoral theses in the School of Electrical Engineering: https://aaltodoc.aalto.fi/handle/123456789/53