Civil Defense – The Use of LoRa Technology for Effective Warning and Alarm of Threats

Purpose: The aim of the research carried out together with technological partners in the Otwock district, as well as the manufacturers’ own research, was to confirm the possibility of using LoRa technology for the purposes of effective alerting about threats and supporting the evacuation of people, as well as, creating own independent, dedicated crisis communication between entities/facilities. Project and methods: This research was intended to confirm the correctness of communication by transmitting messages between the base station and the mobile station, and obtaining confirmation of the execution of the alarm siren activation request using radio and LoRa communications. Control signals were sent from the base station via radio and LoRa communications to the mobile station. The mobile station was driven around the local area of the base station to verify the actual range and reception of signals via both types of communication. The transmitting and receiving antennas were placed on the roof to achieve the greatest possible visibility (range). The mobile station (named "OSP" for testing purposes) was mounted on a vehicle, along with elevated transmitting and receiving antennas outside the vehicle, to ensure the best possible "visibility" between the tower station antenna and the mobile station. The tests were carried out together with technological partners in the Otwock district. Manufacturers’ own research was also used. Results: The measurements provided results including transmission time (s) and RSSI (Received Signal Strength Indicator) (dBm) for both DMR radio and LoRa communications. The test system's base station and mobile station were functionally compatible. It is possible to use DMR and LoRa communications in test system – the maximum distance achieved during testing was 15.7 km. The test system's redundancy was also confirmed in real-world conditions. Conclusions: During all test series, correct redundant DMR and LoRa communication was achieved in 13 out of 16 locations selected for testing (81.25%). Problems with establishing DMR and LoRa communication are influenced by: terrain topography, including the presence of hills between the location of the base station and the mobile station, the degree of forestation/urbanization of the area, including the state of tree foliage, the height of buildings, the presence of high-voltage lines near the masts, the height of antenna masts, local radio communication conditions, including the presence of other radio communication devices, jamming devices.