LoRaLitE: LoRa protocol for Energy-Limited environments

To do in-situ observations of the arctic tundra, many small sensor nodes are used. Reporting the data to remote back-ends is hard because backhaul networks are scarce, and a node cannot expect to see one. Also, there are typically no humans physically close to the nodes to fetch the data and to replace batteries. Consequently, the nodes need a highly available, energy-efficient long range network. While LoRaWAN provides energy-efficient communication for nodes, it does so at the cost of needing an always-on gateway with a high energy consumption. The gateway is also a single point of failure. Instead we propose LoRaLitE for Energy-Limited environments where the gateway enters sleep phases to reduce energy consumption. The sleep phases of the nodes are coordinated accordingly. For high availability, any end-node with a backhaul-network can be elected to become the gateway. We conducted a series of simulation experiments to document the performance behavior of both LoRaWanand LoRaLitE. The results show that the LoRaLitE gateway spends from 10 to 10,000 times less energy than a LoRaWAN gateway. A LoRaLitE node spends from 13% to 42% more energy than a LoRaWAN node. The achievable bandwidth for LoRaLitE is only insignificantly smaller than for LoRaWAN. A LoRaWangateway needs a relatively large, heavy battery. If the gateway fails, assuming a new gateway can be elected, several nodes must have similar large batteries to be able to take over as the gateway. This is impractical to achieve for more than a few nodes because the nodes become more expensive, harder to camouflage, and impractical to deploy. A LoRaLitE gateway on the other hand only needs a battery like any other node. Even if all nodes need larger batteries than for the LoRaWancase, the increase is in practical terms insignificant. We conclude that LoRaLitE makes it realistic to use LoRa for nodes on the arctic tundra, providing for insignificant increased energy usage at the nodes, insignificant reduced bandwidth, but with significant increase in gateway availability. LoRaLitE also provides for an easier deployment in practice because all nodes can be kept small and light,