Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Cell Selection Algorithms for Terrestrial Trunked Narrow Band Radio Systems(Izmir Institute of Technology, 2017) Karataş, Azad; Özbek, BernaSince the interest in mobile communication sector is increasing day by day, it makes traffic volume problem more important. There are different works focused on developing more secure and qualified service for professional users and companies. The Professional Mobile Radio (PMR) system, specially developed for professional users in the communication sector, can be offered to the service of professional users and companies with the desired specifications. With the Tetra system, which is one of the PMR systems, users can get more advanced technological services than the conventional PMR systems. Cell selection algorithms have a great importance for these systems which are needed for more reliable, private and seamless communication. In this thesis, we present two novel cell selection algorithms that can be applied to the Tetra based PMR systems. In these algorithms, both the received power of users and the fair distribution of the overall system are considered. Performance evaluation of algorithms with different traffic characteristics is considered in different environments.Master Thesis Cell Selection Algorithms for Conventional Narrow Band Wireless Systems(Izmir Institute of Technology, 2017) Yılmaz, Saadet Simay; Özbek, BernaPublic safety organizations provide a stable and secure environment for the society. Wireless communication between public safety officers is very important to transmit voice or data during an emergency crisis. When the public communication networks can not provide service during crisis, disaster and high traffic cases, Professional Mobile Radio systems (PMR) such as conventional Association of Public Safety Communications Officials (APCO25) and trunked Digital Mobile Radio (DMR) systems are needed to improve the service quality and to provide uninterrupted service provided to the users. While providing continuous voice and data service, it is very important to efficiently select the base station to be served and to ensure that a mobile user can seamlessly attach from one base station to another base station while moving within a cell. In this sense, it is critical to determine the base station to be served by efficient cell selection algorithms. Cell selection is the process of deciding the base station which provides services to the users. Cell selection plays an important role in balancing the system load and thus overall system performance. By means of efficient cell selection algorithms, it is aimed to reduce the waiting time and to connect a base station as soon as possible while establishing reliable transmission link for PMR systems in emergencies.Master Thesis Cell Selection and Interference Coordination Techniques for Heterogeneous Wireless Networks(Izmir Institute of Technology, 2015) Mahmuda, Subaha; Özbek, BernaThe rapid growth of traffic demands during past years, has led to the immense deployment of heterogeneous wireless networks consisting large-scale macro cells overlaid with multiple tiers of small cells. This is conceived as the major capacity and performance enhancement coordinator by means of increasing the spectral efficiency per unit area. However, heterogeneous networks implementation comprises new technical challenges related to interference issues and throughput deterioration. Advanced interference coordination techniques are introduced to handle these challenges. The usage of range expansion allows captivating more users and hence attaining performance improvement, however causes extra downlink interference. This becomes exquisite for higher bias values; hence the benefits convert into significant deterioration. To overcome these issues, range expansion should be jointly designed with inter-cell interference coordination. The main objective of this thesis is to analyze the concept of heterogeneous network, the cell selection strategies including range expansion, interference coordination schemes and energy efficiency. The performance evaluations are obtained to different macro-pico base stations deployment scenarios for heterogeneous network by using various cell selection algorithms with and without interference coordination depending on frequency allocation schemes to figure out their impact on the system performance for different contours.