الفهرس 
Cognitive Radio and Radio Spectrum UnderutilizationOnly 14 pages are availabe for public view
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Abstract
Static spectrum allocation techniques are incapable of meeting the
enormous demand for spectrum access posed by new wireless
communication technologies such as 5G. This highlights the need for
cognitive radio (CR) to enable dynamic spectrum access. The
cognitive radio can sense the wideband spectrum, looking for
spectrum holes that can be used by secondary users (SU). However,
sensing the wideband spectrum necessitates the use of high-rate
samplers, which are impractical due to hardware complications and
high costs. As a result, compressive sensing (CS) was suggested to be
used to sense the wideband spectrum with fewer number of
measurements exploiting that the radio spectrum has a sparse
representation due to its underutilization by primary users (PUs). In
order to enhance spectrum sensing performance, researchers proposed
to incorporate PU spectrum usage information into the process of
spectrum sensing to improve spectrum sensing performance and
reduce the number of compressive measurements required for
spectrum recovery. Spectrum usage information can be obtained
through pilot signals, geo-locational databases or through evaluation
of previous spectrum sensing results.