An Adaptive and Lightweight Spreading Factor Assignment Scheme for LoRaWAnNetworks

Presently, a long-range wide area network (LoRaWAN) uses an adaptive data rate (ADR) by aiming to provide consistent and energy-efficient communication to the Internet of Things devices. The ADR manages both the spreading factor (SF) and transmit power at the end device (ED) and network server-sides. However, the performance of ADR is severely affected by the variable channel conditions, resulting in massive packet loss. Therefore, we propose two schemes: the initial SF assignment scheme (I-SFA) during the deployment phase and a recovery method called adaptive SF assignment based on the interference (A-SFA). The I-SFA assigns the best SF to EDs based on the received power that a gateway would receive from ED. Whereas A-SFA is used as a recovery method when a collision between two packets of the same SF occur, the A-SFA changes the SF. Hence, it reduces the chances of future interference and thus improves the packet delivery ratio. Simulation results show that the proposed schemes perform better in terms of packet delivery and energy consumption compared to the existing methods.