# Smart Waste Collection System with Low Consumption LoRaWAN Nodes and Route Optimization
## 4 Case Study: Region of Salamanca
### Network Coverage Study  
This section presents an initial study of the LoRaWAN coverage in the region of Salamanca. The terrain was extracted to identify the best locations for placing the antennas. The best options were towns with the highest altitudes in the area with easy-to-access internet to reduce costs. Figure 8 shows the height in meters of each town intended to receive coverage in the proposed case study.  
Radio Mobile [88; 89]--which is widely used to study radio frequency coverage--has been employed for studying the coverage. We have selected this tool over others like CloudRF [90] because it supports (just like CloudRF) the Longley-Rice propagation model (also known as Irregular Terrain Model ITM) and it is free to use. Based on previous data, we decided to deploy a network in the region consisting of nine Gateways, located, as shown in Figure 9, in Vitigud  
Figure 8: Towns in the case study and their corresponding altitudes in meters.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Shipments/day**} & \multirow{2}{*}{**Measurements/day**} & **Estimated Consumption** & **Measured Consumption** \\  & & **(mAh per day)** & **(mAh per day)** \\ \hline
12 & 12 & 6.18 & 6.84 \\
12 & 24 & 7.5 & 7.8 \\
24 & 24 & 25.488 & 26.88 \\
24 & 48 & 28.128 & 32.16 \\
48 & 48 & 104.3232 & 107.04 \\ \hline \hline \end{tabular}
\end{table}
Table 5: Measurements, shipments and consumption ratesde San Esteban (West), La Alberca, La Hoya and Guijuelo (South), la Fuente de San Esteban (East) Ledesma (North) and Salamanca.  
Figure 9 also shows the network coverage in dBm on the map. Using the terrain and the properties of LoRa technology, coverage can be provided to all the towns of the region as well as surrounding ones with no more than nine antennas in the area.  
This makes the deployment cost really low because several towns and their demarcations are covered by one Gateway, reducing the total cost of the deployment.  
Variables employed in Radio Mobile to perform the coverage study are (1) for the base station, transmitter power of 0.5 W, receiver threshold of 0.0316 \(\upmu\)V, line loss of 2.5, omnidirectional antenna, antenna gain of 13 dBi and a height of 20 m, and (2) for the nodes, transmitter power of 0.025 W, receiver threshold of 0.0316 \(\upmu\)V, line loss of 0.1, dipole antenna, antenna gain of 2 dBi and a height of 1 m. These parameters were set according to the recommendations in ERC-REC-70-3E [91], European regulations regarding the radio frequency band of 868 MHz which is a public bandwidth for European Low Power Networks (LPWAN).  
The coverage map in Figure 9 is a view of merged Cartesian coverage where the transmission is specified by the node.  
After the theoretical coverage study, several tests were performed in areas with lower coverage to test if the model employed in this case study was correctly adapted to real conditions. This resulted in the possibility of deploying a network in cases where rural areas use this technology, such as in smart farming domain works. Having this kind of infrastructure promotes the development of applications in this domain, even more if the deployed network includes LoRaWAN and The Things Networks and allows access to the network for the whole region.  
Figure 9: Coverage map of the study performed with the application, Radio Mobile.