【文件属性】：
文件名称：spectrum sensing\Spectrum sensing in cognitive radio networks_ requirements, challenges and design trade-offs [cognitive radio communications]
文件大小：176KB
文件格式：PDF
更新时间：2012-08-03 05:18:43
cognitive radio Spectrum sensing
Opportunistic unlicensed access to the (tem-
porarily) unused frequency bands across the
licensed radio spectrum is currently being inves-
tigated as a means to increase the efficiency of
spectrum usage. Such opportunistic access calls
for implementation of safeguards so that ongo-
ing licensed operations are not compromised.
Among different candidates, sensing-based
access, where the unlicensed users transmit if
they sense the licensed band to be free, is partic-
ularly appealing due to its low deployment cost
and its compatibility with the legacy licensed sys-
tems. The ability to reliably and autonomously
identify unused frequency bands is envisaged as
one of the main functionalities of cognitive
radios. In this article we provide an overview of
the regulatory requirements and major chal-
lenges associated with the practical implementa-
tion of spectrum sensing functionality in
cognitive radio systems. Furthermore, we outline
different design trade-offs that have to be made
in order to enhance various aspects of the sys-
tem’s performance.