Аспекти на просторен диверзитет за контролата на пристап кон медиум во когнитивни радио системи

Abstract

The synergy between Cognitive Radio, and concepts that exploit spatial diversity can contribute to the development of wireless communication systems with significantly improved performance compared with today’s (legacy) systems, with respect to the system throughput as well as the number of active users. Although the spatial diversity aspect is intensively researched paradigm in various fields of wireless communications, as well as in Cognitive Radio, the number of works that analyze its impact and utilization as a core part of the Cognitive-MAC layer is very limited. This issue opens the possibility for the development of new and more efficient Cognitive-MAC techniques and mechanisms. This thesis proposes three novel Cognitive-MAC techniques/mechanisms that aim to maximize the usability of the physical layer in Cognitive Radio systems, i.e. its characteristics (in terms of spectrum sensing and sharing, system capacity, etc.) through efficient exploitation of the spatial diversity aspects.