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Spectrum Sharing in Cognitive Radio Networks

Waqas Ahmed

出版	Victoria University (Melbourne, Vic., 2012
URL	http://books.google.com.hk/books?id=8SxZAQAACAAJ&hl=&source=gbs_api

註釋

Years of growth in wireless communication services and conservative spectrum allocation policies by government regulators have led to spectrum scarcity. On the other hand, spectrum measurement campaigns have indicated that the actual occupancy of most licensed frequency bands is quite low. In recent years, Cognitive radio has emerged as a promising solution to increase spectrum occupancy and tackle spectrum scarcity. Cognitive radio enables the unlicensed (secondary) user to establish a communication link in licensed spectrum on the condition that there is no or minimal interference to the licensee (primary user). In this thesis, the two main facets of spectrum sharing in cognitive radio networks are investigated; interweave access and underlay access. The former is an orthogonal scheme, where the secondary user only transmits in white space (idle primary user spectrum). The latter is a shared scheme in which concurrent primary and secondary transmission is allowed, subject to any co-channel interference at the primary being below an acceptable limit.