# A Long-Distance Communication Architecture for Medical Devices Based on LoRaWAN Protocol
## 2 Related Works
There are trade-offs in every technology choice, but the features of the LoRaWAN specification in network architecture, the device classes, security, and mobility optimization, address the widest variety of potential IoT applications. The results obtained in the IoT domain and LoRaWAN-based communications so far have been disseminated for the Internet of Things and for the LoRaWAN-based communications protocol in the research papers such as [15; 16; 17; 18]. Currently, new efficient technologies are being developed and used with the main concern based on energy efficiency and long-distance data transmission, called LPWANs (Low-Power Wide-Area Network). The LoRaWAN specification is an LPWAN communication protocol, which uses the LoRa modulation, and it was developed to connect wireless devices over long distances. LoRaWAN focuses on the requirements of the Internet of Things, such as mobility and location services, two-way communication, and end-to-end security [11]. The LoRaWAN technology can transmit data over long distances, with transmission speeds between 0.3 kbps and 50 kbps and supports secure communications for data packets between 19 and 250 bytes [19]. LoRaWAN allows communications over distancesof more than 18 km with low energy consumption; the batteries used have a lifespan of at least 4 years. The LoRaWAN enables a transmission power of 25 mW in an 868 MHz SRD860 band on a record distance of 766 km that has been reported in special conditions in August 2019 [20]. It is also an emerging technology that is beginning to be used in broad areas such as the Internet of Things (IoT) [9], the Industrial Internet of Things (IIoT) [21], smart cities [22], health [23], etc. The LoRaWAN was designed for sporadic communications from a relatively large number of nodes [24]. In the following, some examples of research related to the use of LoRaWAN are presented. In [25], the development of a LoRaWAN network infrastructure that is used in monitoring activities in the marine environment is analyzed. The transmission parameters are analyzed in the specific context of an industrial aquaculture facility, establishing a transmission channel from an offshore monitoring structure equipped with a LoRaWAN transmitter, to a shore reception device composed of two LoRaWAN gateways. In conclusion, even using the most unfavorable network settings, the test results show that efficient data transmission can be achieved at a distance of 8.33 km [26]. In [18], the authors did research on the LoRa network architecture and they concluded that compared to other modulation techniques, the LoRa modulation technique offers a high communication link budget as well as better interference immunity. Other results published in [23] propose a new mobile medical device that can be integrated into an existing medical application. What was interesting is that the device is able to make a diagnosis based on data taken in real-time remotely for patients with heart disease. Thus, ECG-type investigations were also allowed for patients who cannot go to the family doctor or to a specialist for various medical reasons or who are in disadvantaged environments and who also cannot receive specialized medical services. There are few references in the relevant research database regarding the use of LoRaWAN protocol in the healthcare field because LoRaWAN has recently appeared on the market. Starting from medical devices proposed in papers [23; 27; 28; 29] and based on the results published in papers [18; 20; 21; 22; 24; 25; 26; 30; 31; 32; 33] for LoRaWAN communication, the aim of this paper is represented by the use of the LoRaWAN protocol for long-range communication on medical devices. LoRaWAN specifications [31; 32] describe that LoRa uses a communication channel with a bandwidth of 125 kHz, 250 kHz, or 500 kHz and spreading factors (SF) (in the range 7 to 12) to control the data rate of the transmitted signals (see Table 1).