Power Saving in LoRa Linear Networks Through Self Synchronization

This paper describes an implementation of reduced duty cycle power saving for lightly loaded, multi-hop, LoRa linear networks. LoRa linear networks are a natural fit to many real-world IoT deployments such as along tunnels, highways and railway lines. Reduced duty cycle power saving requires nodes to be in a low power state until a scheduled message is expected whereupon they go into full power mode, process the message, reschedule the next time they expect another message and re-enter low power mode. This approach is challenging to use in meshed networks but is feasible for linear and near linear networks. To demonstrate the feasibility and to quantify the power savings in such networks we implemented LoRa linear networks with a single source generating data every ten seconds with four relays and a single destination. We experimented with four different network topologies and measured power consumption. Using reduced duty cycle reduced average power consumption of source nodes by 80%, relay nodes by 71% and destination nodes by 79%.