**6.1.2 Optical fiber**

Optical fiber can be used as a medium for communication. Because of its flexibility, fiber optic can be bundled as a cable. As mentioned at the beginning of this section, signals are transmitted through the media by a type of waveform. In fiber cables, the signal is a light wave; either visible or infrared light. Essentially, two types of fiber optic cables including optical power ground wire (OPGW) and all-dielectric self supporting (ADSS) are used in power industries (Shahraeini et al., 2010).

OPGW cable combines the function of grounding and communication. This kind of cable can be used in transmission or distribution lines. In transmission lines, OPGW is replaced with shield wire and is suspended above the lines (Marihart, 2001).

Wide Area Measurement Systems 317

UBW, which is standardized under the name IEEE 802.15.3, can use frequencies from 3.1 GHz to 10.6 GHz. UBW allows data rate up to 480 Mbps at the range of several meters and a

Zigbee has been created to become a wireless standard for remote control in industrial fields. It makes very low-cost WPAN for applications that are not too much bandwidth hungry (Fourty et al., 2005). Zigbee allows data rate of 250 Kbps at 2.4 GHz at the range of up to 10 meters (IEEE 802.15.4) and data rate of 20 Kbps at 900 kHz at the range of up to 75 meters (IEEE 802.15.4a). Recently, Zigbee is widely used to create home area communications between smart meters and smart home equipments (Shahraeini et al.,

The WLAN technologies connect devices via a wireless distribution method (typically spread-spectrum or OFDM). Wi-Fi is a popular WLAN technology that provides high speed connection on short ranges. In recent years, because of the lack of more suitable metropolitan wireless networks, Wi-Fi has also been used at the metropolitan level. Wi-Fi networks are not suitable for moving devices and they take down in a few kilometers per hour movement. IEEE 802.11 is a set of standards that carry out Wi-Fi (Fourty et al., 2005;

**IEEE 802.11:** theoretical data rate 2 Mbps - 2.4 GHz unlicensed band (The first standard

**IEEE 802.11b:** theoretical data rate 11 Mbps - range of 100 meters to a maximum of a

**IEEE 802.11a:** theoretical data rate 54 Mbps - range of approximately thirty meters - 5

**IEEE 802.11g:** theoretical data rate 54 Mbps - range of a hundred meters - 2.4 GHz

**IEEE 802.11n:** theoretical data rate 320 Mbps - about thirty meters range - uses two

WiMAX, GPRS, GSM, CDMA and 3G mobile Carrier services are four WMAN technologies, which are used for WMAN communication. The descriptions of these technologies are as

**WiMAX**: Worldwide Interoperability for Microwave Access (WiMAX) is a communication protocol, which provides fix and fully mobile data networking. WiMAX is based on the IEEE 802.16 standards and its most popular one is 802.16e-2005. Unlike WLAN technologies e.g. Wi-Fi, WiMAX is designed to operate as a WMAN. Various kinds of WiMAX work with both FCC licensed frequencies and unlicensed frequencies. Licensed WiMAX works in the range of 10 to 66 GHz and unlicensed WiMAX works in the range of 2 to 11 GHz. WiMAX theoretical data rate is 70 Mbps with a range of up to a maximum of 50 km with a direct line of sight (LOS). Near line of sight (NLOS) conditions seriously limit their range (Fourty et al.,

rate of 110 Mbps at a range of up to 10 meters (Fourty et al., 2005).

**6.2.2 Wireless Local Area Network (WLAN)** 

Shahraeini et al., 2010). These standards are as follows:

few hundred meters - 2.4 GHz unlicensed band.

**6.2.3 Wireless Metropolitan Area Network (WMAN)** 

of the series. It was released in 1997 and clarified in 1999).

2010).

GHz band.

follows:

unlicensed band.

2005; Shahraeini et al., 2010).

bands 2.4 GHz and 5 GHz.

Unlike OPGW, ADSS is a self supporting cable and it does not include any metal component. In fact, they are designed to be fastened into towers or poles underneath the power conductors. Moreover, ADSS is ideal for installation in distribution poles as well as transmission towers, even when live-line installations are required (Marihart, 2001; Nordell, 2008).
