# Wireless Communication Technologies for Smart Grid Distribution Networks +
## 2 Available Wireless Technologies for Smart Grid Communications  
The communication system is the key component for monitoring and control tasks in the smart grid infrastructure [3]. Different communication technologies, either wired or wireless, are available for the electric utilities that comprise the different sections of the grid. The smart grid paradigm proposes three main sections: generation, T&D, and customer levels. The development of standardized communication structures has begun at the customer level, where developed countries are gradually modernizing energy metering equipment. The communication between smart meters and the backhaul utility is known as the Advanced Metering Infrastructure (AMI). The AMI is an advanced instrumentation technology enabled by real-time sensing and data communication to gather and convey raw measurements. Communication technologies must be chosen to address various requirements in the different parts of the AMI. The AMI's communication architecture is depicted in Figure 1.  
The Neighborhood Area Networks (NANs) and Home Area Networks (HANs) of the AMI infrastructure are suitable for wireless deployment, as distances are relatively short. Information is concentrated in data aggregation points (DAPs). The backhaul network connecting the AMI head end and the DAPs can either be wireless or wired. The link between the DAPs and consumers requires NANs with coverage of a larger distance. Each DAP can connect to hundreds of smart meters (SMs). Elements responsible for sensing the parameters of power lines are usually referred to as sensor nodes. The projected locations of these sensor nodes (i.e., on utility poles in overhead distributed lines and on outer conductor surfaces in underground lines) suggest that the standards of both HANs and NANs may be adequate for defining their communication technologies roadmap. Many communication protocols have been proposed for the composition of NANs and HANs, as well as for other sections of the smart grid (such as the backhaul). A list of the most popular communication technologies considered adequate for different smart grid sections is shown in Table 1.  
Technologies for NANs have to provide a radius of coverage in the range of thousands of meters. The reliability of the communication channels between DAPs and smart meters (SMs) dictates that the spectrum used will have to be exclusive or interference-free. Consequently, the most suitable candidates need to be either licensed or leased wireless solutions. HANs have requirements that are not as stringent as those of NANs. In general, the message arrival rate within a customer premise is not as high as that between SMs and DAPs. They have been recognized with the generic name of \"last-inch access\". A comparison of the desired characteristics of different NAN and HAN communication technologies can be found in Table 2. \begin{table}
\begin{tabular}{c c c c c} \hline
**Technology** & **Spectrum** & **Data Rate** & **Coverage Rate** & **Limitations** \\ \hline
**GSM** & 900–1800 MHz & Up to 14.4 kbps & 1–10 km & Low data rates \\
**GPRS** & 900–1800 MHz & Up to 170 kbps & 1–10 km & Low data rates \\
**3G** & 1.92–1.98 GHz & 384 Kbps–2 Mbps & 1–10 km & Costly spectrum fees \\  & 2.11–2.17 GHz (licensed) & & & \\
**5G** & 3 to 90 GHz & 5–10 Gbps & 20–40 km & Costly spectrum fees \\
**WiMAX** & 2.5 GHz, 3.5 GHz, 5.8 GHz & Up to 75 kbps & 10–50 km & Not widespread \\  & 1–5 km & & & \\
**PLC** & 1–30 MHz & 2–3 Mbps & 1–3 km & Harsh, noisy channel environment \\ \hline
**ZigBee** & 2.4 GHz–868–915 MHz & 250 kbps & 30–50 m & Low data rates, short range \\ \hline \end{tabular}
\end{table} 
Table 1: Overview of communication technologies for the smart grid [5]. Figure 1: Architecture of the AMI (re-drawn from [PERSON] et al. [4]). In the literature, the preferred topology for smart grid applications at the level that has been discussed is wireless mesh. This technology enables any node in a network with routing capabilities to perform self-healing functions in a smart grid.