## 2 Related Works and Overview
### Internet of Things (IoT)
When it comes to wireless technologies, there are a number of technologies that are able to communicate with a long distance between the nodes. Among these technologies are Worldwide Interoperability for Microwave Access (WiMax). This technology is implemented under the IEEE 802.16 standard, being a wireless interface for metropolitan networks that has as objective, to provide a communication infrastructure that has compatibility and interoperability between any equipment in the IEEE 802.16 standard in order toprovide connectivity for home, business and hotspot use. WiMAX is similar to Wi-Fi, but it adds more recent features, aiming at a better communication performance, allowing higher speeds. WiMAX has been studied to provide communication between SG applications due to its performance and long range, which makes it a great candidate for technology that will be used in an outdoor and indoor environment [106]. WiMAX supports large groups of simultaneous users and also has more sophisticated distances and QoS than Wi-Fi. However, network management is very complex, the cost of implementation and equipment is quite high and has as a requirement to have the licensed spectrum [107]. Still in this context, the Global System for Mobile (GSM) emerged to offer the communication service for cell phones and devices that need connectivity via the Internet or other means of communication such as Short Message Service (SMS) or connection, thus GSM was responsible for standardization of mobile telephony. And because it is a technology that supports millions of devices, has low power consumption of the final equipment, has high flexibility, is suitable for cases of different use and still has open industrial standards, becomes a very interesting option to be used in the scenario of SG [108, 109]. However, GSM has some limitations that should be considered when planning which technology to use for this communication infrastructure, such as high prices to use the services providers of the network and increasing costs from the licensed spectrum to the price to be paid for the use of the band in each device. Making a very simple survey for comparison purposes, a GSM node that is used for tracking cars costs around US 9.00 per month for using the infrastructure to send the geolocation data from the car to a server in the cloud [110]. That is, thinking about the residential scenario, it will be unfeasible to use GSM for all SPs and SSs spread around the house. But perhaps it is a viable option to promote communication between SMs and EEC [111]. Moreover, it is worth noting the diversity of technologies that are in this content as Third Generation (3G)/Fourth Generation (4G)/Long Term Evolution (LTE) [112] and especially the emerging technology that is currently the Fifth Generation (5G) [113, 114]. Finally, among the technologies that stand out in the current state of the art for the SG context are the (LPWAN) with the LoRaWAN technology added with LoRaMESH, which are technologies that have a high range with low energy consumption, in addition, they are low-cost technologies only that have as limitation the low data band rate [115, 116]. Within this context are two technologies that are SigFox and LoRa [117, 118]. Both are homological technologies, low cost, long range and low power consumption, and are used in the context of point to point, star through a gateway or mesh. These technologies have two major advantages besides cost, they are technologies that can reach long distances and yet remain reliable and with high security standards. The disadvantages are that these equipments operate with 7 different ranges of Spread Factory (SF) and depending on their configuration or distance to the gateway, can generate high latencies in communication. Moreover, this is one of the factors that leads to low power consumption. Another important point to note is its low bandwidth that makes communication restricted in terms of package size, but this has already been studied in order to standardize ways of sending and receiving packages divided [119].