## 6 Model
### Scenario  
Analyzing altogether the four technologies studied, we can say that BLE is used for short-range wireless connectivity with a transmission rate lower than that achieved by WiFi. BLE is characterized by transmitting small amounts of information at low frequency and allows creation of mesh networks with low energy consumption. This advantage of mesh networks takes advantage of some devices as repeaters. With respect to WiFi, there is currently an extensive infrastructure already installed that transfers data and can handle large amounts of data to provide broadband connectivity. In this technology, there is a greater loss of information, although there is greater sensitivity. In the network of the common networks of a business or academic environment, the network is saturated because there are usually many connected devices. It is an adequate standard for file transfer, but it consumes too much energy to develop IoT applications. WiFi is optimized to have many nodes connected to the same access point without causing too much packet saturation. ZigBee is a wireless technology focused on domestic and industrial applications and has significant advantages such as low consumption in complex systems, superior security, robustness, high scalability, and capacity to support many nodes. Zigbee works in the same frequency band as BLE with low data rate. One of the great advantages of ZigBee is that it presents a mechanism for a node to know when to transmit depending on the communication channel. This reduces collisions when there are multiple devices simultaneously. LoRaWAN is designed to implement wide-area networks (WANs) with specific characteristics to support mobile, bidirectional, economic, and secure communications for IoT, Machine to Machine (M2M), smart cities, and industrial applications.  
The considered network is composed of a sink node and a set of homogeneous sensor nodes, which are randomly scattered in the interested area. Figure 5 is an example of one of the sensor installations on the front of a tree in a building near the entrance to the university campus. The nodes have a plastic protection box and are of easy installation.  
Figure 6 shows an example of the frames captured in the _thethingsnetwork_ web application (www.thethingsnetwork.org). In this interface, through the console tab, we can see the applications that we have activated and properly configured. In each of them, an Application ID is configured to differentiate the device and a description of it. In the Data tab the configuration of the packets  
Figure 5: Sensor in a tree in the center of a building near to the entrance of the university campus.  
transmitted and received by the sensor can be found. Within the characteristics of the packets, there are the reception and transmission times, the packet count ID to know which packet is lost and the sensor data to observe the changes depending on the application. If we detail the Uplink or Downlink tabs, we find the data presented in Figure 7. Here the components of the Fields and the Metadata are described. In the Fields, we have important information about the variables that we are analyzing, such as the sensor's battery. In the Metadata, we find parameters of physical layer performance, MAC layer, and network layer, such as frequencies, modulations, interference and other parameters also related to the gateway for each technology.