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Enhancing Spectrum Utilization In Dynamic Cognitive Radio Systems, Dusadee Treeumnuk
Enhancing Spectrum Utilization In Dynamic Cognitive Radio Systems, Dusadee Treeumnuk
Electrical & Computer Engineering Theses & Dissertations
Cognitive radio (CR) is regarded as a viable solution to enabling flexible use of the frequency spectrum in future generations of wireless systems by allowing unlicensed secondary users (SU) to access licensed spectrum under the specific condition that no harmful interference be caused to the licensed primary users (PU) of the spectrum. In practical scenarios, the knowledge of PU activity is unknown to CRs and radio environments are mostly imperfect due to various issues such as noise uncertainty and multipath fadings. Therefore, important functionalities of CR systems are to efficiently detect availability of radio spectrum as well as to avoid …
Spectrum Adaptation In Cognitive Radio Systems With Operating Constraints, Deepak R. Joshi
Spectrum Adaptation In Cognitive Radio Systems With Operating Constraints, Deepak R. Joshi
Electrical & Computer Engineering Theses & Dissertations
The explosion of high-data-rate-demanding wireless applications such as smart-phones and wireless Internet access devices, together with growth of existing wireless services, are creating a shortage of the scarce Radio Frequency (RF) spectrum. However, several spectrum measurement campaigns revealed that current spectrum usage across time and frequency is inefficient, creating the artificial shortage of the spectrum because of the traditional exclusive "command-and-control" model of using the spectrum. Therefore, a new concept of Cognitive Radio (CR) has been emerging recently in which unlicensed users temporarily borrow spectrum from the licensed Primary Users (PU) based on the Dynamic Spectrum Access (DSA) technique that …
Analysis And Optimization Of Dynamic Spectrum Sharing For Cognitive Radio Networks, Manish Wadhwa
Analysis And Optimization Of Dynamic Spectrum Sharing For Cognitive Radio Networks, Manish Wadhwa
Electrical & Computer Engineering Theses & Dissertations
The goal of this dissertation is to present the analysis and optimization of dynamic spectrum sharing for cognitive radio networks (CRNs). Spectrum scarcity is a well known problem at present. In order to deal with this problem, dynamic spectrum sharing (DSS) was proposed. DSS is a technique where cognitive radio networks dynamically and opportunistically share the channels with primary users. The major contribution of this dissertation is in analyzing the problem of dynamic spectrum sharing under different scenarios and developing optimal solutions for these scenarios. In the first scenario, a contention based dynamic spectrum sharing model is considered and its …