## 4 IoT Multi-Sensor System for Remote Patient Monitoring
### Patient Monitoring System  
Considering the previously identified communication protocol requirements, the LoRaWAN protocol [37; 38] meets performance criteria such as high coverage radius, low costs, the possibility of integrating a large number of nodes, and developing a scalable system that can comply with the requirements of high-density wireless sensor network scenario suitable for urban non-LoS conditions.  
Figure 4 presents the proposed system architecture, which includes, the LoRaWAN gateway (GW), the sensors installed in the wearable device that monitors the patient's vital signs and the network server (NS) that acts as a relay between the LoRaWAN network and the local monitoring center. All the collected data are stored at the monitoring center where medical staff oversee the health status of the patients. The information is conveyed through the LoRa modulation technology for long communication distances between the  
Figure 3: COVID-19 effects on the human body.  
Figure 2: COVID-19 disease symptoms.  
GW and the patient's wearable device using IP-based technologies for the data transmission between multiple GWs and the NS.  
The LoRaWAN architecture consists of LoRa transceivers installed in the IoT multi-sensor wearable devices and GW modules that are communicating directly with the NS. The integrated IoT multi-sensors send management and configuration commands to the LoRa transceiver whose main purpose is to transmit the message to the connected GW module. Since the communication protocol is an aloha-type wireless sensor network, end-devices are allowed to transmit arbitrarily [39]. The transceiver integrated in the IoT multi-sensor device is of class A type, meaning the communication is initiated only from the multi-sensor node side. This ensures that the energy consumption of the multi-sensor node is the lowest possible from all LoRaWAN communication classes available, allowing for long-term operation.  
The main compromise of the LoRaWAN communication protocol is the limited time intervals in which the node can receive messages from the application server, but this mechanism is not an issue. Thus, after a message is sent to the NS, the node listens for any server messages only for a limited time interval. This disadvantage does not reduce the level of performance for the designed architecture.  
Many local municipalities worldwide have already installed or have access to the city developed infrastructures so the wearable devices can be easily enrolled and added as an extension to the existing configuration with no supplementary costs. The medical staff can easily monitor many patients, and if a patient's condition worsens, rapid intervention is possible. If the LoRaWAN communication protocol is used, then the system has no additional licensing costs or monthly fees like other communication protocols presented in Table 1, so the maintenance cost for the proposed system is low.  
The system can be used both in institutional quarantine areas and in the case of people who are in solitary confinement at home. By setting up automatic alerts, a very large number of people can be monitored by a small number of medical staff in a centralized manner. Thus, we provide smart usage of the limited resources available in the pandemic context, contributing to saving as many lives as possible.