Flooding in LoRa Mesh Networks

Although LoRa is most well-known for the substantial distances over which it can transmit, it also has some characteristics that make it attractive as a mesh networking technology. In particular, it overcomes one of the main objections to using flooding as a routing mechanism in mesh networking. Flooding involves each node in the network forwarding a copy of every message it receives. Flooding is robust and simple, but unfortunately, if multiple nodes in the mesh receive a message, it typically results in many copies of the same message being received at the destination. However, a LoRa receiver synchronizes with only one transmitter and treats other messages as noise. Because duplicate messages are ignored, flooding can be designed to be much less wasteful of radio resources than mesh networks based on other wireless technologies. In this paper, we demonstrate that LoRa's physical layer mechanism ensures that only one copy of a message is forwarded by a node, regardless of how many copies it receives. We then present results from a simple LoRa mesh network to demonstrate that, for LoRa nodes, flooding is an efficient method of routing.