Page 265 - From Smart Grid to Internet of Energy

236 From smart grid to internet of energy

FIG. 6.19 Cognitive WAN architecture in the SG communications.

data transmission over long distances for monitoring and control applications of
the SG systems. A WAN architecture comprises the combination of core net-
work and backhaul network [68, 76]. The former is responsible for communi-
cating with control center where the communication infrastructure is carried out
by employing either fiber optics or cellular systems to provide low latency and
high data rates. The latter aims to provide broadband communication links for
both the NANs and monitoring devices. In addition, employing the CR technol-
ogy in this network not only reduces installation costs, but also provides several
improvements in terms of coverage, system capacity and flexibility [80]. Fur-
thermore, the NGWs can effectively communicate with the CBSs since the each
of them behaves as a SU in lieu of an AP in the CR-enabled backhaul networks.
In the cognitive WANs, spectrum brokers are intentionally utilized to con-
trol licensed spectrum bands allocated to the NANs as can be seen from the
Fig. 6.19. When the dynamic changes of data in the network are taken into
account, a spectrum broker should not only react to the demand promptly,
but it should also efficiently deploy the available licensed frequency bands
to satisfy data transfer needs. When a WAN serves in a wide area, some NANs
may employ the same frequency bands devoid of leading to interference to each