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214 From smart grid to internet of energy

FIG. 6.2 Principles of cognitive cycle.

generally support two kinds of detection methods that are called feature detec-
tion and blind detection. In the first method, the CR devices exploit a priori
knowledge of PU waveforms for idle channel detection. In the second method,
detection process is blindly performed by using energy detection or autocorre-
lation detection where there is no requirement for a prior knowledge [24, 25].In
addition, the CRNs may exploit cooperative SS methods in order to enhance
performance [26–29]. Besides, the CR devices should support well-timed SS
process because of the fact that the CR devices should clear out the channel
if a PU returns to its licensed spectrum band.
Spectrum Decision: This process is essential for choosing best idle channel
(s) of the PUs to meet QoS needs of CR devices. After the SS results are ana-
lyzed, CR devices can additionally decide which idle channel can be exploited
according to aims and requirements of particular applications. Therefore, the
process firstly analyzes every idle channel depending on both the SS data
and statistical data of each licensed user [30]. Later, spectrum management
and handoff functions of CR devices authorize them for selecting the most
appropriate channel(s) and channel switching opportunities in order to fulfill
the QoS targets. After channel detection process is completed, each CR device
reconfigures its system parameters for supporting communication over new