## 4 Results and Discussion
### Evaluation of Communication Range and Channel Attenuation Modeling
As shown in Table 8, during the scenario selection process, the selected scenarios (the ones with the white background) are those in which the percentage of successful transmissions is the highest among all collected results within each particular scenario. However, when several options have the same percentage of packet delivery, the combinations of communication parameters that enable lower energy consumption are chosen within the selection process. According to previously conducted analyses, they include combinations in which smaller transceiver power values are selected (LP mode, compared to HP mode) due to lower energy consumption, a lower value of the SF parameter (7, compared to 10), if possible, considering the quality of communication (the higher percentage of packet delivery), and the higher value of the CR parameter (4/5). The presented results reveal that there is no packet loss up to a distance of 500 m, regardless of the NLOS conditions. Moreover, within 2 km and at a more extended range from the transmitter, in the case of NLOS (non-line-of-sight blocked by some obstacles and possible interference from other radio systems), there are situations where a complete loss of communication occurs. However, the number of delivered packets can be increased with adequately selected communication parameters, as, for instance, higher SF and, if necessary, lower CR values since combinations with minimum CR are more susceptible to noise. Moreover, the following must be observed. Despite some sources, the packet delivery level increases with the amount of data sent. Also, with a shorter packet length, the percentage of packet delivery is higher in some cases. Therefore, even in NLOS conditions \begin{table}
\begin{tabular}{c c c c c c c c c c c c c c c} \hline \hline Packet (P) Size: & \multicolumn{8}{c}{Pmax} & \multicolumn{8}{c}{Pmin} \\ \hline Transceiver Power Mode: & \multicolumn{3}{c}{Low Power (14 dBm)} & \multicolumn{3}{c}{High Power (20 dBm)} & \multicolumn{3}{c}{Low Power (14 dBm)} & \multicolumn{3}{c}{High Power (20 dBm)} \\ \hline SF: & 7 & \multicolumn{3}{c}{10} & \multicolumn{3}{c}{7} & \multicolumn{3}{c}{10} & \multicolumn{3}{c}{7} & \multicolumn{3}{c}{10} & \multicolumn{3}{c}{7} & \multicolumn{3}{c}{10} \\ \hline CR: & 4/5 & 4/8 & 4/5 & 4/8 & 4/5 & 4/8 & 4/5 & 4/8 & 4/5 & 4/8 & 4/5 & 4/8 & 4/5 & 4/8 & 4/5 & 4/8 \\ \hline Scenario & \multicolumn{8}{c}{**Delivered Packets (DP) in Relation to Sent Packets**} \\ \hline Close Proximity (distance: <100 m) & 100\% & 100\% & 100\% & 100\% & 100\% & 100\% & 100\% & 100\% & 100\% & 100\% & 100\% & 100\% & 100\% & 100\% & 100\% & 100\% & 100\% \\ \hline Urban NLOS (distance: 500 m) & 100\% & 100\% & 100\% & 100\% & 100\% & 100\% & 100\% & 100\% & 100\% & 100\% & 100\% & 100\% & 100\% & 100\% \\ \hline Urban NLOS (distance: 200 m) & 0\% & 0\% & 40\% & 100\% & 40\% & 40\% & 40\% & 40\% & 40\% & 40\% & 60\% & 100\% & 60\% & 60\% & 100\% \\ \hline Suburban NLOS (distance: 500 m) & 0\% & 0\% & 60\% & 60\% & 40\% & 0\% & 40\% & 40\% & 40\% & 60\% & 80\% & 40\% & 80\% & 40\% & 80\% \\ \hline Rural LOS (distance: 7000 m) & 40\% & 60\% & 80\% & 100\% & 80\% & 100\% & 60\% & 10\% & 40\% & 80\% & 80\% & 100\% & 80\% & 60\% & 100\% \\ \hline Rural NLOS (distance: 7000 m) & 0\% & 0\% & 40\% & 0\% & 0\% & 0\% & 0\% & 0\% & 0\% & 0\% & 40\% & 0\% & 0\% & 0\% & 0\% & 60\% \\ \hline \hline \end{tabular}
\end{table} 
Table 8: Measured packet delivery ratio. at distances over 5 km, it is possible to achieve communication, while it is necessary to consider the usage of higher SF values. In further analyses of the quality of communication, the performance metrics used on the receiving end are the Received Signal Strength Indicator (RSSI) and the Signal-to-Noise Ratio (SNR). The conducted analyses consider the power received at the end of the symmetrical half-duplex communication link between the transmitter and the receiver.