# State of the Art and Trends Review of _Smart Metering_ in Electricity Grids
## 3 Smart Metering Technologies  
The successful implementation of a _Smart Metering_ system highly relies on the choice of communication technology. Different aspects such as the final application, the features of the location, and the topology electricity grid, among others, highly influence the choice of the most suitable technology. There is a wide range of available technologies for the communication network of a _Smart Metering_ system; however, there is currently no communications technology that fits all needs and sometimes more than one technology is used in the same deployment [11; 24; 25]. Figure 2 shows a worldwide tendency for communication technologies from 2011 to 2020. Two main groups can be distinguished in _Smart Metering_ technologies: _wireless_ and _wired_. Wireless technologies usually entail less deployment costs and quicker installation than wired options. Additionally, they are more suitable for remote or hardly accessible locations [26]. However, wired alternatives for _Smart Metering_ do not present interference problems from other sensors of the network that may occur in wireless technologies. Table 3 summarizes the main technologies and their features for _Smart Metering_ systems. Figure 2: Communications node segmentation by technology, world markets, 2011–2020 (Source: Navigant Research [27]). Reprinted with the permission of Navigant Research, “Smart Grid Networking and Communications”, published by Navigant Research, 2012. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Wireless** & **Data Rate** & **Frequency Bands** & **Distance** & **Advantages** & **Drawbacks** & **Deployment/Projects** \\ \hline \multirow{3}{*}{RF-Mesh} & \multirow{3}{*}{-} & \multirow{3}{*}{902-928 MHz} & \multirow{3}{*}{Dependes on} & Coverage can be increased with multiple hops, _All_ hoc communication links & Tools to be proprietary offering, Performance & Most reloulous in USA \\  & & & & & & \\  & & & & & & \\  & & & & & & \\  & & & & & & \\  & & & & & & \\  & & & & & & \\  & & & & & & \\ \hline \multirow{3}{*}{Cellular} & \multirow{3}{*}{3C–4G} & \multirow{3}{*}{60-200 kbps} & \multirow{3}{*}{190 MHz} & \multirow{3}{*}{Up to 50 km} & Wide-range coverage Low maintenance Lower power & Individual connections are expensive. Moderate bit rates & \multirow{3}{*}{Dataset City (UK) Essential Energy (AUS)} \\  & & & & & & \\  & GSM & 14.4 kbps max. & 900-1800 MHz & 1-10 km & Resolution & & \\  & & & & & & \\ \cline{2-7}  & GPS & 170 kbps max. & 900-1800 MHz & 1-10 km & \multirow{3}{*}{Low cost Low power consumption} & Low bit rates Security issues & Energy Demand Research Project, EDBP (13G) \\ \cline{2-7}  & ZigBlee & \multirow{3}{*}{4G-RayNN} & \multirow{3}{*}{721 kbps} & \multirow{3}{*}{12.4-2.4835 GHz} & \multirow{3}{*}{1-100 m} & \multirow{3}{*}{\ \begin{tabular}{} \end{tabular}  } & \multirow{3}{*}{ \begin{tabular}{} \end{tabular}  } \\ \cline{2-7}  & ZigBlee & \multirow{3}{*}{20-250 kbps} & \multirow{3}{*}{1600 MHz/250  
Radio Frequency_ (_RF_) technologies for _Smart Metering_ deployments are specially spread in the United States. In _RF_ technology, measurements and other data are transmitted by wireless radio from the _SM_s to a collection point. The data is then delivered to the _CC_ for processing. The best-known topology is _RF mesh_, in which the _SM_s talk to each other and form a _Local Access Network_ (_LAN_) cloud to a collector [8]. _RF mesh_ has an acceptable latency and large bandwidth and generally operates at free license bands. In addition, the _self-healing_ characteristic of the network enables the communication signals to find another route via the active nodes, if any node should drop out of the network [28]. However, this tends to be a proprietary offering and the terrain and long distances typical of rural areas are a challenge for its deployment. It is common to find _RF-cellular_ technologies used in _Smart Metering_ deployments in the United States. Their strengths are the wide coverage and low maintenance costs that they offer.