Page 243 - From Smart Grid to Internet of Energy

216 From smart grid to internet of energy

FIG. 6.4 Block diagram of the spectrum mobility process.

mobility is a process to sustain wireless communication by smoothly switching
communication channels [38]. In order to accomplish this process, there are two
required transactions called as spectrum handoff and connection management.
Steps of the spectrum mobility process are illustrated in Fig. 6.4.
The connection management operation is related to adjusting or updating
connection parameters while the spectrum handoff operation is related to
changing an active transmission from a channel to a different idle channel.
In addition, protocol stacks of CR device have to ensure easy access to various
layers in order to decrease latency in spectrum mobility process. Regarding the
spectrum handoff, the CR devices may use classic methods employed in con-
ventional wireless networks because of decrease in channel quality.

6.2.1 Importance of CR for smart grid systems
The CR is considered as an encouraging technologyto meetcommunication,stan-
dardizationandsecurityrequirementsofsmartgrid(SG)systems[39–42].Inaddi-
tion, supporting several traffic types is very crucial for the SG systems [43].Joint
spatial and tentative spectrum sharing can be utilized in the SG applications, par-
ticularly in demand response management (DRM) applications [44]. Machine-to-
machine(M2M) communicationisa new typeofcommunicationaimingtoenable
connectivity among devices without human intervention. Nevertheless, a great
number of connected devices may seriously restrict the spectrum of current com-
munication networks. Therefore, the use of CR technology in the SG systems may
beanappropriatealternativetoreducespectrumscarcityoriginatedfromtheM2M
communications[45].Furthermore,theCRNsmaybeanexcellentoptionforcom-
munication requirements of SG systems since they can support a wide variety of
communication applications [41, 46–48]. The superiorities of CR technology uti-
lization in the SG systems can be summarized as follows.
l Several wireless communication systems (i.e., Bluetooth, ZigBee, and Wi-
Fi etc.) operate at 2.4 GHz license-free frequency band. Household appli-
ances may also generate powerful electromagnetic waves. Further, wireless
communication channels suffer from electromagnetic interferences gener-
ated electrical devices. The SG meters (smart meters (SMs)) that are home
area network (HAN) components of SG systems also operate at 2.4 GHz