Αρχιτεκτονικές ασύρματων δικτύων για μείωση του κόστους λειτουργίας
The present thesis studies wireless networks created as an expansion to their wired counterparts to extend the coverage of the latter in points where wired communication was impossible as well as to use for connecting with devices supporting solely wireless connectivity. Wireless networks, beginning from their initial development, are connected with the architectures, which build and organize them. In the first chapter, we present in the past architectures used and considered as important scientific achievement at the time. Some of them are used even today for various reasons (e.g. upgrade cost, compatibility, etc.). Still, as technology advances and the need around wireless networks rise, it is necessary for the architectures to evolve and adapt. Therefore, in the second chapter, we continue with the presentation of new generation architectures, such as network slicing, cloud-RAN, small cells, relays, cognitive radio, NFV, which are analyzed with regard to their advantages and disadvantages, their capabilities, and their practical application. Most of the communication providers (especially in 5G networks) begin building the backbone of their network using these architectures. In the third chapter, we apply a SWOT analysis in each of the presented architectures, in order to specify those which can lead to cost reduction of the wireless network, maintaining simultaneously or even expanding its general capabilities. Finally, in the fourth chapter, we refer to the conclusions about the new wireless network architectures that have emerged from SWOT analysis tool.