Page 308 - From Smart Grid to Internet of Energy

274 From smart grid to internet of energy

first two layers of Fig. 7.5 that are physical layer (PHY) and MAC layer. Both
layers meet measurement requirements of smart grid and are primarily
improved for sensor networks. The improvement of PHY and MAC layers pro-
vided energy efficiency and increased reliability in the transmission medium.
PHY layer manages the sensor data transmission and receive operations while
MAC layer operates the protocols concerning medium allocation among the
sensor nodes. Due to variety of sensor networks, numerous technologies oper-
ating on PHY and MAC layers have been developed [42]. Some outstanding and
widespread communication technologies are presented as follows:
IEEE 802.15.1 and Bluetooth: RFID and IEEE 802.15.1 technology that
Bluetooth has also been included performs the data transmission at 2.45 GHz
Industrial Scientific and Medical (ISM) frequency band. RFID tags and systems
use shift keying methods as for amplitude shift keying (ASK), frequency shift
keying (FSK), and phase shift keying (PSK). On the other hand, Bluetooth
decreases power consumption since it transmits data between devices in a short
coverage range which is proper for energy efficient smart grid applications.
After the first implementation of Bluetooth technology, the most recent
improvements have been performed by the development of Bluetooth 4.1, or
Bluetooth Low Energy (BLE) in another name, that provides higher speed
and IP support for IoT. It is noted that BLE has been benefited from power sav-
ing mode features of IEEE 802.11b and coverage area has been extended at least
10 times of its antecedent versions. The PHY data rate of BLE 5.0 extends up to
2 Mb/s while its variant BLE PSM provides up to 11 Mb/s PHY data transmis-
sion rate, and coverage area up to 100 m [32].
IEEE 802.15.4: IEEE 802.15.1 and its improved variant BLE provides high
data rate for transmission, but they lack on supporting WSN and large network
connections that is particularly required for smart metering and monitoring
applications. IEEE 802.15.4 WPAN protocol has been developed to create a
cross-layer between PHY and MAC for low-rate WPAN (LR-WPAN). IEEE
802.15.4 has been accepted as a suitable infrastructure for IoT, M2M, H2M,
and WSN application due to key features as low power consumption, low cost,
sufficient data transmission rate, and operability that are crucial for smart grid
applications. The PHY layer of IEEE 802.15.4 presents success on short-range
communication and obtained a widespread acceptance that results the adoption
to four major standards (ZigBee, WirelessHART, ISA100.11a, and WIA-PA).
However, it is not same for MAC layer in terms of transmission success and
reliability in industrial application. Therefore, WirelessHART, ISA100.11a,
and WIA-PA improved IEEE802.15.4 MAC layer by adding different technol-
ogies according to specified industrial applications. It can be said that the most
prominent contribution to widespread use of IEEE 802.15.4 is provided by Zig-
Bee technology, which deals with low rate data transmission and is capable to
manage large number of sensor nodes for WSNs in a smart grid environment.
ZigBee supports three frequency channels at 868 MHz for Europe, 915 MHz for
America, and 2.4 GHz for worldwide utilization.