# Wireless Communication Technologies for Smart Grid Distribution Networks +
## 2 Available Wireless Technologies for Smart Grid Communications
### IEEE 802.22  
The wireless regional area network is an alternative to mainstream broadband wireless that uses the white spaces in the television spectrum. It proposes to use cognitive radio technologies to exploit the unused spectrum in the frequency range allocated to television \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Coverage** & **Technology** & **Range** & **Latency** & **Reliability** &
\begin{tabular}{c} **Cost and Ease of** \\ **Deployment** \\ \end{tabular} \\ \hline \multirow{3}{*}{**HAN**} & WiMAX & 30 km & Low & High & Medium/Medium \\ \cline{2-6}  & UMTS/LTE & 30 km & Low & High & Medium/Low \\ \cline{2-6}  & 802.22 & 30 km & Medium & Medium/Low & High/Medium \\ \hline \multirow{3}{*}{**NAN**} & WiFi & 200 m & Medium–High & Low–Medium & Low \\ \cline{2-6}  & ZigBee & 100 m & Low–Medium & Medium & Low \\ \cline{1-1} \cline{2-6}  & Bluetooth & 100 m & Low & Medium & Low \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Comparison of wireless communication technology candidates from the perspective of their suitability for NANs and HANs [4]. broadcasting. As the spectrum used is not dedicated, the latency in data transmission could be higher than other solutions for HANs. Cellular networks are a good option for communication between smart meter nodes and utility far nodes, i.e., in NANs. The cellular communication technologies available to utilities for smart metering deployments include 2G, 2.5G, 3G, WiMAX, and LTE. A data transfer interval of 15 min between the meter and the utility produces a large amount of information, which requires a high data rate connection. GSM and GPRS are currently being used to enable communication between smart meters and the backhaul utility. GPRS is used for data, with a typical rate of 30-80 kbps, whereas EDGE provides 160 to 236 kbps. These ranges are those of cell phones, so coverage is not a concern with these technologies. Other wireless technologies being used for smart grid projects include CDMA, WCDMA, and UMTS, even in the backbone of smart grid communications, as in the case of Verizon's 3G CDMA. SP AusNet in Australia chose WiMAX as the technology for dedicated communication between smart meters and the central system of SP AusNet. Another technology that is being used for this kind of task is 4G. Relaying functionality has also been incorporated into 3 GPP Release 10 (commonly known as LTE Advanced), which will allow extended coverage using relay/repeater stations. Since cellular network infrastructure is already built, it presents a cost-effective feature. Cellular networks provide sufficient bandwidth for intermittent applications, security control, and wide coverage. The big drawback of these technologies is their reliability because the services are shared by customers, resulting in network congestion or a decrease in performance under emergency or abnormal situations. This is not acceptable in power utilities. One option for addressing these issues is the implementation of private cellular networks. From these solutions, WiMAX, which implements IEEE's 802.16 standard for metropolitan networks, is a leading candidate for providing connectivity between DAPs and SMs. It is based on orthogonal division multiplexing access (OFDMA), which assigns slices of the frequency spectrum to different users, avoiding interference among the users and increasing the spectral efficiency of the system. WiMAX is an attractive solution in the sense that its structure is much less sophisticated compared to rival cellular standards such as Long-Term Evolution (LTE). It has a minimum range of 8 km and data rates ranging from 45 to 75 Mbps. Up to this point, wireless technologies for smart grids have been outlined. They share some common disadvantages, which can be summarized as follows:  
* Poor performance in electrically noisy and harsh environments. * Concerns about security. * Limited transmission range (except for cell phone technologies) and low data rates. * Non-industrial-level reliability. * Standards that are not robust.