# The Role of Smart Meters in Enabling Real-Time Energy Services for Households: The Italian Case
## 5 Architectures for Real-Time Home Services  
Real-time services aim at sending metering data with the appropriate frequency and latency to customer devices or to authorized third parties. As discussed above, IHDs range from a simple external display to more sophisticated smart appliances or home automation and EMS. They can present information to the customer either locally (in the proximity of the SM) or remotely (e.g., through smartphone applications). Authorized third parties are entities providing value-added services to customers. Such services can be as simple as directly providing the measurements to the final user, or controlling the behavior of customers' appliances in order to better manage energy consumption. In general, the authorized third parties will communicate to customer devices through a public Wide Area Network (WAN). We identify four possible architectures for real-time services, with different complexity and degree of involvement of the consumer in the deployment of the services:  
1. The SM sends the data to the consumer IHDs, which locally uses the data without forwarding them to any other device or entity. 2. The SM makes the data available to the devices connected to the consumer's Home Area Network (HAN). 3. The SM sends the data to an authorized third party. 4. The SM sends the data to an IHD acting as a gateway (IHD-GW), which then makes the data available for locally connected devices and any authorized third party. These architectures are suitable for consumers with different constraints and needs. The SM should be flexible enough to support all of them even at the same time. Figure 3 shows the first architecture, in which the SM directly sends the data to the consumer devices. In its simplest form, the IHD for this case could be, for instance, an external display showing real-time measurements to the customer or a device with limited home automation capabilities. The main characteristics of this architecture are:  
* Data are sent only to the IHDs and no third party is involved. * The customer does not provision any home communications infrastructure. * The IHD must be able to talk to the SM by means of a shared communications medium and a common communications protocol. This architecture is most likely to be deployed for households with limited technology needs and makes it possible to increase user awareness about electricity consumption with a limited cost. Figure 3: Architecture 1: the SM directly sends the data to the In-Home Devices (IHDs). Figure 4 shows the second architecture, in which the SM is connected to the consumer's HAN and makes metering data available for locally connected IHDs. Eventually, an authorized third party can withdraw these data from the HAN, moving them through a WAN. In turn, the third party will be able to communicate to consumer smart devices locally connected to the cellular network or to the Internet. The main characteristics of this architecture are:  
1. The SM must be able to connect to the HAN. 2. The SM must be able to talk to the IHDs by means of a standard communications protocol. 3. If a third party is involved, the customer must ensure a connection to the public data network. Architecture 2 is the most flexible solution, because it makes it possible to communicate with both locally connected devices and multiple authorized third parties, such as appliance control centers or energy management services. The main drawback is that it loads the end user with the burden of providing HAN and WAN access. Figure 5 shows the third architecture, in which the SM sends the data to an authorized third party through a public WAN. In turn, the third party provides the data to the IHDs through the same network. The main characteristics of this architecture are:  
1. The SM is connected to a public WAN, which must be available in the area. 2. The SM sends metering data only to a third party. 3. The customer is not required to provision any home communications infrastructure.