# A Visitor Assistance System Based on LoRa for Nature Forest Parks
## 3 Related Work  
The use of positioning systems other than satellite-based has been increasing due to the growing demand for Location-Based Services (LBS), mainly in places where satellite communication is limited or unavailable. Those studies are important to the design of our visitor assistance system. On the other hand, the integration of tourism activities, environment preservation, and safety demands efficient communication systems. [PERSON] et al. [8] discuss the importance of conservation tourism and protected destination system as a trade-off between healthy activity and economical investment for the host area. The authors suggest that a potential approach is the remote sensing data collected by individuals. Remote sensors/platforms with human components are interesting because humans have discretionary abilities influencing sensing that are not shared by other animals or platforms that are coupled with sensors. A system capable of transmitting positioning data using LPWAN in outdoor environments is developed in [9] by [PERSON], demonstrating that it is feasible to locate a static terminal with an accuracy of 100 meters. The remote node sends data using the LoRaWAN protocol. Nearby gateways receive this data and forward the packets via UDP/IP to the server along with information about the received signal, such as the exact time the packet was received, the RSSI, the frequency, etc. The server then processes the data from different gateways and routes messages to the application using an MQTT client (Message Queuing Telemetry Transport) [10]. Finally, an algorithm running on the application server estimates the position using the Time Difference Of Arrival (TDOA) method. In [11], [PERSON] et al. present a long-range WSN for tracking the geographic location of moving objects. In the proposed system, the geographic location information of moving objects is collected with a GPS and sent through LoRa modules. The results demonstrated the usability of GPS technology to collect various additional data, such as speed and direction of travel, related to tracking the geographic location of moving objects. This work also reflects the high potential of LoRa technology as a reliable wireless communication interface for transmitting data from long-range sensors. [PERSON] et al. [12] presented technology comparison scenarios for IoT concepts on rescue monitoring. The paper focuses on rescue monitoring, and the goal is the usage of Wi-Fi and LoRa for data transmission from IoT devices. A LoRa based gateway and Wi-Fi Router is used to connect the end-device. The collected data is sent to server applications as captured from installed sensors on the IoT modules and can be displayed to authorized users through a web or mobile application. The results through simulation and real-time experiments indicate that LoRa can be an ideal candidate for rescue monitoring. Similar to the forest, maritime communications, presented by [PERSON] in [13], are challenging due to the adverse transmission conditions and the lack of a pre-provided infrastructure. Communications in areas closer to the shore allow services as boat tracking and telemetry, data collection from moored monitoring systems, etc. The authors present a boat tracking and monitoring system based on LoRa and present the results extracted from a case of study where real-training sessions of Optimist Class sailboats have been monitored. A transmission range study is also presented. Some studies estimate the location based on the RSSI (Received Signal Strength Indicator) values of the signal received from the infrastructure elements. In [14], RSSI is used in a system for locating small turtles on the Wildlife Institute of India. Four fixed points are used covering a square area, called by the authors of the environmental matrix. Based on the RSSI reading taken previously along the sides of the square, adjacent grid points are mapped. These points allow defining the limit values for the measured signal.