SALSA: A Scheduling Algorithm for LoRa to LEO Satellites

Satellites are going to revolutionize the Internet of Things (IoT) connectivity enabling ubiquitous coverage targeted by 5G and upcoming 6G networks. While potentials satellite IoT unquestionable, many challenges still remain unsolved. In present work, we design a Long Range Wide Area Network (LoRaWAN) with mobile gateways (GWs) installed on Low Earth Orbit (LEO) satellites. We address synchronization issues due intermittent link availability between End Devices (EDs) GW, propose Scheduling Algorithm for LoRa LEO (SALSA). SALSA ensures reliable communication, avoiding packets drops packet collisions, using Time Division Multiple Access (TDMA) approach, rather than classic ALOHA-based LoRa. The uplink transmissions EDs scheduled considering period, footprint, specific visit time each ED. Two different policies proposed: First Come Served (FCFS), FAIR policy. Simulation results, obtained in real conditions, satellites visibility, demonstrate better performance achievable (regardless policy) compared standard policy outperforms FCFS giving all an equal chance transmit, even those that visited last satellite. can be further improved larger constellations