Radio wave propagation of LoRa systems in mountains for Search and Rescue operations

Search and Rescue (SaR) operations in mountain environments are common events. However, current transceivers for mountain SaR suffer from a limited range, making operation slow. The emerging Low-Power WideArea Network (LPWAN) technology is very promising thanks to its extended range and to the long battery life. LoRa (Long Range) is one of the most popular LPWAN. In this paper, we experimentally evaluate the effectiveness of body-worn LoRa in an extreme mountain environment by measuring the range and deriving the path loss by the means of a log-normal model. The measured LoRa range in the mountain landscape, under the condition of at least 50% of packet reception, was 300 m. This values, even if much smaller than the usual ranges of LoRa in flat environments (some kilometers), is, however, more than five times the ARVA operating range in the same conditions. Accordingly, LoRa system can be considered valuable for faster SaR operations.