# Evaluating LoRaWAN Connectivity in a Marine Scenario
## 3 Results and Discussion
The best results were obtained in LOS independently of the distance between the end-nodes and the gateways: this demonstrates that in LOS conditions it is possible to obtain reliable transmission over large portions of the sea, even in the case of proximity to the coast using gateways on elevated positions, thus able to observe the marine area of interest without obstacles. \(PRR\) estimates reveal a quite constant value close to 1, indicating that the transmissions occurred in the connected region [38]. The reaching of the upper limit for \(PRR\) was expected since our setup was conceived to obtain the highest sensitivity at the expense of a higher percentage of potentially missed packets. In order to analyze the presence of multipath propagation effects on the channel, the \(RSSI\) and \(SNR\) values were archived for each gateway and for each received LoRaWAN packet depending on the position of the vessel. With the exception of LT I/O Controller 1, for which the received power for the LoRa packet was at the limit of the technology (i.e., close to \(-120\) dBm), all the employed gateways detected comparable \(RSSI\) values with respect to the transmitting end-nodes (Figure 5). These results support that the multipath propagation effect was not dominant during the experiment and that the main component of the signal was that of the LOS path. Results still highlight how the LOS condition is fundamental to obtaining a reliable LoRa transmission. Furthermore, it is noteworthy that the two non-commercial end-nodes developed on purpose for the specific marine application show performances very similar to the commercial Field Test in terms of \(RSSI\). In the case of free LOS, \(SNR\) values assume positive values close to the threshold of 10 dB, which is considered almost optimal for LoRaWAN transmission, regardless of the distance between the end-nodes and the receiving gateway (Figure 6). Unlike the other end-nodes, the transmissions by LT I/O Controller 1 seemed to be strongly limited by the presence of a noise floor signal, probably due to the noise of the front-end circuit, such as to invalidate the transmission, and this agrees with the observed high packet loss ratio. The same type of analysis has been carried out during the test performed in October 2020 taking advantage of the availability of the R/V Dallaporta during the oceanographic campaign ICOS20. Table 4 shows the results in terms of packet loss ratio for three gateways operating on land and the two days of tests. The overall dataset comprises 23 and 67 packets transmitted by Field Test for the 19 October and 20 October, respectively; 55 (on 19 October) and 67 (on 20 October) for the LT I/O Controller 1 and 8 on the first day and 59 in the second day for the TIAMO 3 end-node. On 20 October, LT I/O Controller 1 was operating onboard outside the period during which gateways LG308 1 and LG308 3 were active on land, thus no packets were received as \begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & & \multicolumn{4}{c}{**End-Node**} \\ \cline{3-6}
**Gateway Id.** & **Position Id.** & **Field Test** & **TIAMO 3** &
\begin{tabular}{c} **LT I/O** \\ **Controller 1** \\ \end{tabular} & **Spectrometer** \\ \hline LG308 1 & Crevari & 0.622 & 0.690 & 0.888 & 0.958 \\ LG308 2 & Mount Gazzo & 0.183 & 0.281 & 0.155 & 0.309 \\ LG308 3 & Mount Fasec & 0.177 & 0.239 & 0.488 & 0.175 \\ LG308 4 & Rigli & 0.044 & 0.042 & 0.777 & 0.567 \\ LG308 5 & Scarpino & 0.550 & 0.802 & 0.977 & 0.938 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Packet loss ratio for the coastal test performed with end-nodes installed on the passenger vessel travelling back and forth in front of the port of Genoa. The geographical positions of the gateways are shown in Figure 0(a). Figure 5: _RSSI_ measured by the five gateways installed in the inland of the city of Genoa. Three end-nodes were carried onboard the passenger vessel travelling in front of the port of Genoa: (**a**) Field Test; (**b**) spectrometer; (**c**) TIAMO 3. The track of the vessel is shown with a grey line.