# Experimental Evaluation of a LoRa Wildlife Monitoring Network in a Forest Vegetation Area
## 2 State-of-the-Art and Related Works
### Related Works  
In this section, we briefly discuss some related deployments of smart agriculture based on LPWAN technology. Next, related works on LoRa signal propagation are presented in this section. There have been several studies on LPWAN technologies applied to smart agriculture applications. LoRa and LoRaWAN occupy the majority of the smart agriculture applications deployment in the literature compared to other LPWAN technologies. This is hardly surprising given the open nature of the LoRa/LoRaWAN specification and availability of off-the-shelf hardware that can be leveraged for experimental research and rapid prototyping. LoRa communication has gained momentum in smart agriculture applications by the scientific community and the industry in recent years. [PERSON] et al. [PERSON] et al. (2018) presented an innovative, power efficient and highly scalable IoT agricultural system based on LoRaWAN network for environmental monitoring in a grape farm. Studies in [PERSON] et al. (2018); [PERSON] et al. (2018); [PERSON] et al. (2018) also followed a similar approach by utilizing LoRa technology for environmental monitoring on a farm. The authors in [PERSON] et al. (2018) investigated LoRaWAN for agriculture-based use cases, in terms of measuring the temperature of a horse stable and also analyzing the soil properties and testing the permeability of agricultural land. The use of LoRa for smart irrigation purposes has also been demonstrated in [PERSON] et al. (2018); [PERSON] et al. (2018); [PERSON] et al. (2018). An IoT monitoring infrastructure to be used for the remote control of offshore sea farms based on LoRAWAN protocol was presented in [PERSON] et al. (2018). The study in [PERSON] et al. (2018) demonstrated the use of LoRaWAN in greenhouses. \begin{table}
\begin{tabular}{c c c} \hline \hline
**SF** & **Bit Rate [kbps]** & **Sensitivity [dBm]** \\ \hline
7 & 5.468 & –123 \\ \hline
8 & 3.125 & –126 \\ \hline
9 & 1.757 & –129 \\ \hline
10 & 0.976 & –132 \\ \hline
11 & 0.537 & –134.5 \\ \hline
12 & 0.293 & –137 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: LoRa configuration parameters for 125 kHz bandwidth. Figure 2: LoRa Frame Structure. Sigfox, on the other hand, is the first LPWAN technology and it has been deployed in some countries for smart agriculture applications. The work in [38] presented the development of an autonomous Sigfox sensor node capable of transmitting data collected by a range of sensors in a vineyard, in order to collect meteorological parameters directly to the cloud. Other studies utilizing Sigfox technology for environmental monitoring have been demonstrated in [39; 40]. The deployment of NB-IoT is another concerning issue, as it requires a hardware upgrade of the existing LTE infrastructure [41]. Despite this, there are several papers that have utilized NB-IoT technology for smart agriculture and wildlife monitoring purposes [42; 43; 44; 45]. The authors in [43] proposed an NB-IoT system for collecting underground soil parameters in potato crops using a UAV-aided network. A real field trial for NB-IoT performance evaluation in rural areas for smart agriculture applications was also demonstrated in [42]. Good coverage performance was achieved compared with the general packet radio service (GPRS) standard. Studies in [44; 45] demonstrated the use of NB-IoT technology in greenhouses. The authors in [46] developed a water quality monitoring system for aquaculture ponds based on NB-IoT technology. Other studies [47; 48; 49; 50] elaborated on the deployment of Ingenu RPMA, EC-GSM-IoT, DASH7, Telensa for smart agriculture applications as summarized in Table 2.  
In regards to LoRa signal propagation, there are a few works [51; 52; 53; 17] that have studied the behaviour of LoRa in forest vegetation to the best of our knowledge. The authors in [17] presented an evaluation of LoRa in three different environments (urban, suburban and rural) to analyze their influence on propagation conditions and performance considering both dynamic and static conditions.