## 6 Results
### Analysis of the Influence of Heights and Polarizations in Densely Wooded Environments  
Wireless communication in densely vegetated environments has been gaining increasing importance due to applications such as environmental monitoring, fire prevention, and search and rescue systems. However, dense vegetation, especially tree canopies, can cause signal attenuation and interference, making it essential to properly select the polarization and height of the transmitter to improve the reliability and quality of transmissions. Wireless signal transmissions in such environments pose unique challenges, where the proper choice of electromagnetic wave polarization can significantly affect transmission performance in this scenario. This section explores the effectiveness of HH (horizontal transmitted and horizontal received) and VV (vertical transmitted and vertical received) polarizations at different heights relative to transmissions at both trunk and canopy levels of trees. The choice of microwave polarization (such as HH and VV) at different heights of transmissions below tree canopies is related to the interaction of electromagnetic waves with vegetation. This interaction can vary depending on the structure and density of the vegetation, as well as the characteristics of the waves used. The relationship between RSSI and SNR in LoRa technology is that RSSI provides information about the overall signal strength, while SNR complements this information by indicating the signal quality relative to background noise. To obtain a more comprehensive and accurate view of the LoRa communication link quality, it is important to consider both parameters. In some LoRa implementations, SNR may be more significant in determining data reception capability than RSSI, especially in environments with high noise or interference. Figure 8 illustrates the measurement points which are in the middle of a dense forest. The transmitter is at the beginning of the way and has a static longitude and latitude; in contrast, the receiver varies in longitude and latitude since it is moving across the way. Figure 8a,b show the RSSI and SNR values, respectively. A detailed analysis of RSSI and SNR according to the transmitter height is below. According with Figure 9, the lowest value for RSSI with vertical polarization is \(-133\) dBm and the highest value is \(-75\) dBm; on the other hand, for horizontal polarization, the lowest value is \(-135\) dBm and the highest value is \(-75\) dBm. In addition, it can be seen that the RSSI values are similar for both polarizations; however, RSSI values for VV show higher values, especially for distances greater than 150 m. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Sample Set** & **Number of Samples** & **\% in Relation to the Total** \\ \hline Training & 3167 & 70\% \\ Validation & 679 & 15\% \\ Test & 679 & 15\% \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Splitting the dataset. Additionally, four VV RSSI values show a decreasing trend around 20 dB each 100 m. For HH, the decrease in RSSI values is around 25 dB each 100 m. This means that the forest plays a significant attenuation role, even over short distances. Figure 10 shows that the minimum SNR for HH is \(-13\), and for VV is \(-9\), the maximum value for HH is 13, and for VV it is 14. Also, the SNR for both polarizations begins decreasing for distances greater than 100 m for SF12 at all heights. However, VV polarization has a stronger and better signal quality in a densely wooded environment, which means that the signal RSSI is stronger relative to the noise, resulting in better communication performance. Additionally, when observing the variations in RSSI and SNR values with distance, it is noted that the forest environment affects both RSSI and SNR even at short distances. In summary, according to Figures 9 and 10, it can be observed that VV polarization performs better in transmission compared to HH polarization for all heights.